Frequently Asked Questions

While both systems pursue the same objective, responsible forest management, they differ in their governance structure and approach. 
In practice, both schemes provide credible assurance that timber originates from responsibly managed forests and can be traced throughout the supply chain. 

This is probably the most common question we receive. 

The simple answer is: both FSC® and PEFC are recognised and respected certification systems that contribute significantly to responsible forest management. 

Rather than asking which certification is "better", buyers should focus on choosing certified timber from reliable suppliers that maintain robust chain of custody systems and a strong commitment to sustainability. At Vandecasteele, we stock significant volumes of both FSC® and PEFC certified timber, allowing customers to make responsible choices according to their project requirements.

Recent regulations such as the European Union Deforestation Regulation (EUDR) have increased the importance of transparency and traceability within timber supply chains. 

Forest certification helps companies demonstrate responsible sourcing practices and complements broader due diligence efforts. Vandecasteele Houtimport has invested heavily in traceability and responsible sourcing systems and became the first company in Belgium certified under the Preferred by Nature Certification Programme for Chain of Custody and Due Diligence Systems, strengthening its ability to support customers with responsible sourcing and EUDR compliance. 

At Vandecasteele Houtimport we have a large range of certified timber species in stock.

One of the biggest misconceptions about timber is that harvesting trees automatically leads to deforestation. 

Responsible forest management works differently. In certified forests, harvesting is carefully controlled, regeneration is planned, biodiversity is protected and the long-term health of the forest remains the priority. Vandecasteele's sustainability strategy is built on the conviction that certified forestry can contribute to the preservation of tropical forests by creating economic value that supports their long-term protection rather than conversion to other land uses. 

Certification therefore plays an essential role in ensuring that forests continue to provide environmental and social benefits for future generations.

Whether you choose FSC® or PEFC certified timber, certification gives you confidence that: 

• The timber originates from responsibly managed forests. 

• Independent audits verify compliance. 

• Forest resources are managed for the long term. 

• Environmental and social considerations are taken into account. 

• Products are traceable through the supply chain. 

For specifiers, contractors and timber merchants, certification is not simply a label. It is a practical tool for supporting responsible forestry, reducing supply-chain risks and demonstrating sustainability commitments. At Vandecasteele Houtimport we have a large range of certified timber species in stock.

Around the world, forests provide essential environmental, social and economic benefits. They store carbon, protect biodiversity, regulate water cycles and provide livelihoods for millions of people. 

Certification systems were developed to give buyers confidence that the timber they purchase comes from responsibly managed forests and can be traced through the supply chain. Today, FSC® and PEFC are the two most recognised forest certification systems worldwide. Vandecasteele Houtimport has been FSC® certified since 1999 and PEFC certified since 2005, reflecting a long-term commitment to responsible sourcing and sustainable forestry.

The key factor is how the forest is managed and how the timber is sourced, not whether the wood comes from a tropical region. Certified tropical hardwood from responsibly managed forests can be a highly sustainable material.

When is tropical hardwood sustainable? 

Tropical hardwood is generally considered sustainable when: 

• It comes from well-managed forests with long-term management plans. 

• Only a limited number of mature trees are harvested, allowing the forest to regenerate naturally. 

• The timber is independently certified, such as FSC® or PEFC. 

• The supply chain is fully traceable and complies with regulations such as the EUDR. 

• Biodiversity, local communities and workers' rights are protected.

A Responsible Sourcing Policy defines how a company ensures that the timber it purchases and sells comes from legal, ethical, and sustainable sources. The objective is to minimise environmental and social risks throughout the supply chain while promoting responsible forest management.

For timber companies, responsible sourcing typically includes:

• Compliance with all applicable laws and regulations, including timber legality requirements and the EU Deforestation Regulation (EUDR).

• Supply chain traceability, ensuring that timber can be traced back to its origin.

• Preference for certified products, such as FSC® and PEFC certified timber, which provide independent verification of responsible forest management.

• Supplier due diligence, including risk assessments and regular evaluation of suppliers.

• Protection of forests and biodiversity, by avoiding sources linked to illegal logging, deforestation, habitat destruction, or unacceptable forestry practices.

• Respect for human rights and local communities, including indigenous peoples' rights and fair working conditions.

• Continuous improvement, working with suppliers and stakeholders to strengthen sustainability performance over time.

At Vandecasteele Houtimport, responsible sourcing is at the heart of everything we do. We carefully select our suppliers and maintain strict due diligence procedures to ensure the timber we offer is legal, traceable and responsibly sourced. By combining robust supply chain controls with internationally recognised certification systems such as FSC® and PEFC, we help our customers make confident and sustainable timber choices.

The EUDR is a European regulation designed to prevent products linked to deforestation from entering the EU market. It requires companies to demonstrate that timber products are legal, traceable and not sourced from recently deforested land

Chain of custody is the documented process that tracks timber from the forest through processing, distribution and final sale. It allows customers to verify the origin and certification status of their timber.

Trees absorb CO₂ while growing and store that carbon throughout the life of the wood product. As a renewable material, timber has a lower carbon footprint than alternative construction materials

Certification schemes such as FSC® and PEFC promote responsible forest management practices that protect wildlife habitats, maintain ecosystem functions and encourage long-term forest stewardship.

Using a wider range of timber species reduces pressure on a small number of popular species and supports better forest management. Vandecasteele Houtimport has long promoted lesser-known timber species as sustainable alternatives for many applications.

The European Union Deforestation Regulation (EUDR) is a European law designed to ensure that products placed on, or exported from, the EU market are deforestation-free, legally produced, and fully traceable. The regulation covers several commodities, including wood and timber products. Its objective is to reduce the EU's contribution to global deforestation, forest degradation, biodiversity loss and climate change.

Under the EUDR, companies must be able to demonstrate that the timber they sell or purchase:

• Was not harvested from land that was deforested after 31 December 2020.

• Has not contributed to forest degradation.

• Was harvested in compliance with the laws of the country of origin.

• Can be traced back to its source through documented supply chain information.

The EUDR replaces the former EU Timber Regulation (EUTR) and introduces significantly stricter requirements regarding due diligence and traceability.

What must timber buyers do?

While the primary legal obligations often fall on operators and traders placing timber on the EU market, timber buyers also play a crucial role in ensuring compliance.

1. Buy from Responsible Suppliers

Timber buyers should work with suppliers who can provide evidence that their timber complies with EUDR requirements. This includes documentation proving legality, traceability and responsible sourcing.

2. Request Traceability Information

Buyers should be able to identify where the timber originated and understand the supply chain behind the product. Reliable suppliers should be able to provide supporting documentation demonstrating the origin of the timber.

3. Verify Compliance Documentation

Before purchasing timber, buyers should ensure that the necessary EUDR-related information is available and that suppliers have implemented appropriate due diligence procedures.

4. Maintain Records

Companies should retain relevant documentation relating to timber purchases so that information can be provided if requested by customers, auditors or competent authorities.

5. Understand that Certification helps but is not sufficient

Certification schemes such as FSC® and PEFC remain valuable tools that support responsible sourcing and risk assessment. However, certification alone does not automatically satisfy EUDR requirements. Companies still need to demonstrate compliance with the specific due diligence and traceability obligations of the regulation.

Why does this matter?

The EUDR is transforming the timber industry by making transparency and traceability more important than ever. Buyers increasingly need confidence that the timber they purchase is:

• Legal

• Responsibly sourced

• Traceable to its origin

• Free from links to deforestation or forest degradation

For timber buyers, selecting suppliers with strong due diligence systems and well-established certification and traceability procedures helps reduce compliance risks and supports responsible forest management worldwide.

In short: EUDR requires timber supply chains to become more transparent than ever before. Timber buyers should choose suppliers who can provide clear evidence of legality, traceability and deforestation-free sourcing.

What is OLB Certification?

OLB stands for Origine et Légalité des Bois ("Timber Origin and Legality"). It is an independent certification system developed by Bureau Veritas in 2004 to verify the legal origin, traceability and legality of timber and timber products.

The certification provides assurance that timber has been legally harvested, purchased, processed and sold in accordance with applicable laws and regulations. OLB is widely used in tropical timber-producing regions, particularly in Central and West Africa and parts of Asia.

OLB certification is based on two main components:

• OLB-FC (Forest Certification) for forest management and logging companies.

• OLB-CoC (Chain of Custody Certification) for processing, trading and distribution companies.

The certification focuses on:

• Legal compliance in forest operations.

• Verification of timber origin.

• Full traceability throughout the supply chain.

• Monitoring and control of timber flows from forest to customer.

An additional OLB+ level includes supplementary social and environmental requirements.

Why is OLB Important?

OLB helps companies demonstrate that their timber originates from legal sources and is supported by robust traceability procedures. It is particularly valuable for companies sourcing tropical hardwoods and supports due diligence requirements for timber procurement. However, OLB certification alone does not replace all legal obligations under regulations such as the EUDR.

Yes. Vandecasteele Houtimport has been operating a due diligence system under the EUTR since 2013 and has further expanded it in recent years in preparation for the EUDR.

We collect information on the origin of the timber, the suppliers involved, the supply chain, geolocation data, legal documentation and relevant risk indicators. This information is assessed through our due diligence system before products are placed on the European market.

In addition, we work closely with external auditors, certification bodies and suppliers worldwide to prepare our supply chains for EUDR compliance.

For products falling within the scope of the EUDR, Vandecasteele Houtimport will provide the relevant EUDR reference numbers through the commercial documentation accompanying the delivery.

This enables customers to demonstrate that the products concerned were placed on the market by an operator in accordance with the EUDR.

Vandecasteele Houtimport is certified under the Preferred by Nature certification programme for both the Chain of Custody (CoC) and Due Diligence System (DDS) scope. This certification confirms the company's commitment to responsible forest management and full traceability of timber products in line with the EU Deforestation Regulation (EUDR).

The certification evaluates whether our procedures meet the requirements for information gathering, traceability, risk assessment and risk mitigation throughout the timber supply chain.

As part of this certification, our processes are audited annually by independent external auditors. These audits verify how we assess suppliers, what information we collect, how risks are evaluated and which measures are implemented when risks are identified.

In addition, we combine this external verification with our own internal controls, supplier assessments, document verification procedures and traceability systems. This helps ensure that timber products originate from controlled and responsibly managed supply chains and that identified risks are properly assessed and mitigated before products are placed on the market.

The level of preparedness varies from supplier to supplier and from country to country.

We have been working with our suppliers for several years to collect the required information and help them prepare for the new requirements. Particular attention is given to:

• Traceability;

• Geolocation data;

• Legal documentation;

• Risk assessment;

• Certification;

• Deforestation-related requirements.

Where necessary, we support suppliers in improving their processes and documentation. At the same time, every supplier continues to be individually evaluated within our due diligence system.

For most customers, the purchasing process itself will change very little. The main impact lies behind the scenes, where more information and documentation are required to comply with legal obligations.

Depending on the product, origin and the customer’s position within the supply chain, the following may become more important:

• Increased focus on traceability;

• Availability of DDS-related information;

• Greater transparency regarding the origin of the timber;

• Additional documentation for certain product flows.

Our objective remains to make compliance as straightforward as possible for our customers while ensuring that products meet all applicable legal requirements.

That depends on your position within the supply chain.

The EUDR distinguishes between different types of market participants, such as operators and traders. Obligations differ depending on whether a company places products on the EU market for the first time or trades products that have already been placed on the market.

When purchasing products that Vandecasteele Houtimport has placed on the EU market as an operator, you do not have to repeat the due diligence process for those products.

Your obligations under the EUDR depend on your role within the supply chain and, where applicable, on the size of your company. In general, you should retain information necessary to ensure traceability of your purchases and sales and make it available to competent authorities upon request.

We recommend that customers always assess the applicable legislation based on their own activities and position within the supply chain.

FSC, PEFC and OLB certification remain valuable tools for responsible forest management, traceability and risk mitigation.

However, the EUDR requires additional information and an independent due diligence assessment by the operator. Certification supports this process but does not replace it.

For this reason, we continue to prioritise certified timber supply chains, combined with our own risk assessment and due diligence procedures.

All timber species with durability class 2 are suitable for cladding. The most popular timber for cladding is Padouk. It is a stable and dense timber specie with a red color. After some months, it becomes a beautiful brown grey cladding. Afrormosia is also a very nice and stable timber specie. It starts yellow brown and becomes brown grey over time. The Western Red Cedar is also very suitable for cladding and is a light weight in comparison with the other timber species. At Vandecasteele Houtimport we have a large range of certified timber species suitable for cladding.

There is no single timber species that is the best choice for every decking project. The ideal timber depends on factors such as durability, stability, appearance, maintenance requirements and budget.

Some of the most popular timber species for high-quality decking include:

• Padouk: Highly durable, stable and low-maintenance. Its vibrant red colour naturally weathers to an elegant silver-grey patina.

• Afrormosia: A durable and stable hardwood with a warm golden-brown appearance that gradually turns grey over time.

• Ipé: Exceptionally hard and durable, offering an extremely long service life even in demanding outdoor conditions.

• Teak: Renowned for its natural oils, excellent durability and comfort underfoot. Often used in premium decking and marine applications.

• Garapa: A lighter-coloured hardwood that combines good durability with excellent value for money.

At Vandecasteele Houtimport, Padouk, Afrormosia and Ipé are among the most popular choices for durable, high-quality decking projects. Their combination of durability, stability and natural beauty makes them particularly well suited for long-lasting outdoor applications. At Vandecasteele Houtimport we have a large range of certified timber species suitable for decking.

All timber species with durability class 2 and 2-3 are suitable for windows and doors. Check the products on our website to find all the timber species. At Vandecasteele Houtimport we have a large range of certified timber species suitable for windows and doors.

Teak (Tectona grandis) is traditionally regarded as the premium timber for superyacht and boat decks because of its unique combination of durability, stability and natural resistance to moisture and rot. Its high natural oil content allows it to withstand harsh marine environments while providing excellent grip, comfort underfoot and a long service life. Vandecasteele Houtimport has a large range of certified Teak products in stock.

Choosing timber for bridges

Selecting the right timber for bridge construction requires careful consideration of durability, strength, stability and long-term performance. Timber bridges are exposed to demanding environmental conditions, including moisture, temperature fluctuations and heavy mechanical loads. Therefore, choosing an appropriate timber species is essential to ensure a long service life and minimise maintenance requirements.

Key Selection Criteria

When specifying timber for bridges, consider the following factors:

• Natural durability against fungal decay and insect attack.

• Mechanical strength to withstand structural loads.

• Dimensional stability to minimise movement and deformation.

• Resistance to weathering and moisture exposure.

• Availability and certification to ensure sustainable sourcing.

Suitable Timber Species

For pedestrian bridges, cycle bridges and structural bridge components, naturally durable hardwoods are often preferred, including:

• Azobé (Ekki): extremely durable and exceptionally strong.

• Okan: excellent strength and durability for heavy-duty applications.

• Bilinga: highly resistant to decay and commonly used in marine and bridge structures.

• Tali: dense hardwood suitable for demanding structural environments.

Sustainability Matters

Timber remains one of the most sustainable construction materials available. When selecting timber for bridge construction, it is advisable to choose products certified under recognised schemes such as FSC® or PEFC, ensuring responsible forest management and traceable supply chains.

In Summary

The best timber for bridges combines high durability, structural strength and long-term resistance to weather exposure. Species such as Azobé, Okan, Bilinga and Tali have proven performance records in bridge construction throughout Europe and beyond.

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This note is a high-level primer for anyone interested in structural timber for low-carbon bridges.

1 Introduction

With the climate crisis and decarbonisation an increasing priority, bridge owners, designers and contractors have a duty to consider the carbon impact of the bridges we build. This paper examines timber as a structural material for low-carbon bridges. It looks at timber’s carbon credentials, the challenges and opportunities of designing in timber, and examples in the UK and abroad. This paper is not a technical guide to timber bridge design, but it may be a starting point for those interested in commissioning or proposing a timber bridge. Where relevant, references include design codes and papers by specialists in this field.

It is easy to acknowledge the importance of timber in historic bridge construction. Before steel and concrete, stone and timber were the main materials of construction. Exposed timber structures were maintained and replaced as required. Protected structures (those with roofs) lasted longer: the best survive to this day (see Appendix), illustrating the importance of designing with the environment in mind.

While timber is applicable to many bridge components: structural (primary and secondary) and non-structural (decking and parapets); the focus of this paper is on structural timber. In this role it has the biggest potential to influence a bridge’s environmental impact.

2 Opportunities

2.1 Sustainability

Timber is widely perceived as a sustainable building material due to its renewable nature, low embodied carbon, and ability to store carbon.

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Renewable resource: Timber is a natural material that can be sourced from sustainably managed forests, with global schemes such as FSC (Forest Stewardship Council) and PEFC (Programme for the Endorsement of Forest Certification) that certify the responsible and balanced use of forest resources while ensuring the long-term health of the forest's ecosystem and the species that live within it. 1 Productive forests usually yield mature trees suitable for glued laminated timber (glulam) within 40 to 60 years. This growing time should be 1/3 or 1/2 of a well detailed bridge’s design life. Longer-lasting structures make the biggest positive impact.

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Low embodied carbon: The processing and fabrication of structural timber requires significantly less energy compared to steel or concrete, resulting in lower A1-A3 (cradle to gate) greenhouse gas emissions. Across these stages of the project lifecycle, each kilogram of glulam accounts for the emission of 0.28kg of CO2e. 2 As industrial processes often rely today on energy from ‘fossil carbon’ (burning coal, oil, gas, etc.), reductions in energy use at this stage have a big impact. This energy advantage also applies to engineered timber products such as glulam and CLT (cross-laminated timber) which rely on adhesives and fabrication. In addition, timber manufacturing is

1 Forest Stewardship Council (FSC), “What is sustainable forestry? Practices & benefits,” published 5 May 2024. Available at: https://fsc.org/en/what-is-sustainable-forestry (Accessed: 17 February 2026).

2 Circular Ecology, “The Inventory of Carbon and Energy (ICE) Database,” v4.1 published 29 October 2025. Available at: https://carbon.tips/ice3 (Accessed: 6 May 2026).

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increasingly powered through renewable energy and on-site biomass CHP (Combined Heat and Power), further reducing the embodied carbon.

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Carbon storage: As trees grow, carbon dioxide is removed from the atmosphere through photosynthesis. Oxygen is released and the carbon is stored as plant matter until it is later released to the atmosphere or the ground in the form of methane or carbon dioxide through decomposition (or incineration if timber is burned in a fire or as fuel). The longer the carbon is stored as timber, the greater the climatic benefit, as it reduces its time as a GHG (greenhouse gas) contributing to global warming. Carbon that is stored within timber (sequestered) is one form of ‘biogenic carbon’. Each kg of glulam stores 1.41kg of CO2e. 2

2.2 Assessing carbon impact

In contravention to most international LCA (life-cycle assessment) standards, stored biogenic carbon is sometimes counted as a negative number when calculating embodied carbon. One risk of this approach is that it can incentivise inefficient use of timber to offset fossil carbon emissions elsewhere on a project. Common assumptions which can be hard to quantify or attribute directly to an individual project include: the growth of replacement trees (continued carbon capture) during the project’s lifetime (positive), or the re-emission of biogenic carbon at end of life (negative). The time value of carbon is important and should be considered, where possible, as part of a dynamic LCA, because carbon emitted now is more consequential than future carbon emissions in relation to meeting global net zero targets. 3

Quantifying the benefits of biogenic carbon stored over a period is complex. The Institution of Structural Engineers (IStructE) suggests that biogenic sequestration is accounted for separately in LCAs. 4 As the future of a timber structure can only be assumed (how long will it last and what will happen when it’s no longer in use?), it is difficult to predict the duration of storage of its carbon. Additionally, the value of carbon varies across tree species and forests (i.e. old growth stores more carbon than plantation growth).

With or without an established method for quantifying the climate benefits of biogenic carbon storage, there are principles to maximise these, as outlined in TheIStructE Technical Position Paper “Structural timber and global greenhouse gas emissions”. 4

•

Prioritise forest carbon storage and biodiversity: Ensure that all timber comes from accountable, well-managed sources that replant trees in a sustainable manner. Old growth should be avoided in favour of faster-growing plantations.

•

Use timber efficiently: Treat timber as a precious resource. Reduce associated emissions by creating as much structure as possible out of a given amount of timber. Use lower-grade timber when possible.

3 Arup, “Buildings & Infrastructure Priority Actions for Sustainability – Embodied Carbon – Timber,” published 5 June 2023. Available at: https://www.istructe.org/IStructE/media/Public/Resources/ARUP-Embodied-carbon-timber_1.pdf (Accessed: 17 February 2026).

4 Institution of Structural Engineers (IStructE), “Technical Position Paper – Structural timber and global greenhouse gas emissions,” published 14 November 2025. Available at: https://www.istructe.org/IStructE/media/Public/Resources/IStructE-Technical-Position-Paper-Structural-timber-and-global-GHG.pdf (Accessed: 17 February 2026).

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Prioritise long-life: Keep carbon locked into timber for as long as possible. Protect structural timber from the elements. Repurpose timber at the end of life, or as a last resort, consider the least impactful way to dispose of it.

2.3 Availability

In climates conducive to forestry, the timber industry operates with efficient supply chains supporting the creation of buildings of all types and sizes. Historically the route from forest to building was direct, relying on regional harvesting, processing and crafting. This remains the case today, partially explaining the prevalence of timber bridges in distinct areas across the globe. The benefits of regional supply chains are significant. Environmentally they minimise transportation while being less susceptible to global politics. By supporting local industry, economic benefits are localised, and infrastructure projects become beneficial on multiple levels.

Despite a healthy interest in timber across the wider UK building sector, current government policy and competition from other land uses restricts the production of structural softwoods suitable for bridges. Around 80% of the timber used in the UK is imported, making it one of the largest timber importers in the world. Unlike nearby Austria, Germany, Finland and Sweden, the UK lacks the means to process timber at scale. Despite the UK’s reliance on imported timber, the “downstream” part of the supply chain is alive and well with specialists currently assembling imported lamellas or beams into prefabricated structural members suitable for buildings. If given the opportunity and incentive to scale up, these engineered-timber companies have the potential to support the UK timber bridge sector.

Some of the relevant softwoods already grown in the UK include Scots Pine, Sitka Spruce, Western Red Cedar and Douglas Fir. These are often faster growing and less dense than imported equivalents resulting in lower structural grades. However, this is less relevant in glulam structures where UK Douglas Fir offers a good balance of strength, durability and suitability to UK growing conditions.

If the demand for structural timber continues to grow, all aspects of the UK supply chain, from forestry through processing, fabrication and installation, should be able to keep pace. This opportunity could bring to the UK the environmental and economic benefits already enjoyed by countries with stronger timber cultures.

2.4 Ability to shape / workability

Engineered timber products can readily be manufactured to custom shapes and sizes. For the cross-sections required for bridge girders, this involves gluing and pressing lamellas in one direction (to build depth), followed by gluing and pressing in the other direction (to build width) – known as block laminated glulam. Termination of lamellas along the length of the girder allows for easy variation of depth to suit structural demand. Even though milling timber down, in order to build it back up, requires energy, it makes curving in one or more directions possible and allows faster growing, lower grades of wood to be used more efficiently in a product that is strong, stable and predictable.

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Figure 1: Block laminated timber beams can vary in cross section and be curved in two directions (image courtesy Ingenieurbüro Miebach and Schaffitzel Holzindustrie)

2.5 Aesthetics

Exposed timber can create a strong architectural statement. Timber’s natural warmth, texture and grain is visually appealing and difficult to replicate with industrial materials. It often adds tactility and a human scale to larger elements. When exposed to sun and weather, untreated timber changes colour and tone, eventually greying with time. Many see this ‘patination’ as a positive feature, softening a structure’s appearance. The rate and degree of transformation is related to exposure. Regardless of one’s aesthetic preference, this transformation should be anticipated.

Figure 2: Exposed structural timber has a unique character (Balingen Bridge by Moxon Architects and Ingenieurbüro Miebach)

2.6 Health & safety, modularity and prefabrication

Structural timber, and particularly engineered timber is typically manufactured off-site in a controlled factory environment. This increases precision and control over hazardous processes such as cutting and assembling, resulting in less disruption on site. The sawdust produced when cutting timber is a hazard that needs to be considered, however it is generally less harmful than dust from steel or concrete. Timber glues can contain harmful chemicals that also need to be considered.

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Timber is relatively lightweight, which presents benefits for transportation, lifting and installation, and it is also non-conductive. Engineered connections allow efficient erection of subassemblies on site. This is similar to ‘building’ design where components serve specific functions related to their material properties. It enables straightforward maintenance and end-of-life disassembly where elements can be reused elsewhere5 or recycled as secondary construction timber or bioenergy feedstock. Glue should be considered when repurposing and disposing, however most modern glues are used in negligible amounts and are benign when reprocessed. While ‘circularity’ is not unique to timber, it is one advantage of a construction method that relies on the assembly of distinct parts (unlike more monolithic steel or concrete structures).

Figure 3: Prefabricated block laminated beams are lifted into position (Baiersbronn Bridge by Moxon Architects and Ingenieurbüro Miebach)

2.7 Good strength-to-weight ratio

Timber has a good strength-to-weight ratio, meaning a lighter structure can carry more load. This has benefits for foundation design. It also makes the material easier and more cost-effective to transport and lift on site. Despite weight savings, timber structures are often bulkier than their reinforced concrete and steel equivalents – this should be considered in design.

Figure 4: Structural properties of timber, steel and reinforced concrete

Material

Mean specific weight 6 [kN/m3]

Characteristic Compressive Strength [N/mm2]

Strength-to-weight ratio

Timber (GL24h)

4.2

24 7

5.7

Steel (S355)

77

355 8

4.6

Reinforced concrete (C32/40)

25

40 9

1.6

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2.8 Composites

In the same way that modern timber bridges benefit from other materials serving supplemental functions (connections, waterproofing, surfacing, etc.), composite structural systems combine timber with concrete or stone. In both cases (for simply supported spans) timber working in tension sits below concrete or stone working in compression. Not only is this structurally efficient, the upper, more durable material protects the timber while doubling as the bridge deck. These systems can be considered for both pedestrian and vehicular bridges. 10 Like other composite structures, thermal compatibility is a key design consideration. Consideration should also be given to moisture content and timber’s anisotropic nature (its directional grain means at times it behaves differently longitudinally vs. transversely).

3 Challenges

Despite these opportunities, modern timber bridges are rare in the UK. This section identifies some of the challenges to designing in timber and ways to overcome them. Before exploring specifics, it is worth considering these high-level factors:

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Material constraints: As with any material, some uses are better suited to timber than others. Advocates for timber acknowledge its limitations: it is by no means a “silver bullet” that can bring environmental benefits to every project.

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Unfamiliarity: The UK is arguably stuck in a cycle that limits the uptake of timber bridges, resulting in historical/cultural bias. The relatively infrequent use of timber bridges means fewer examples of best practice and unfamiliarity with building and maintaining these structures. This lack of experience undermines confidence when commissioning and proposing new bridges, perpetuating the lack of built examples.

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Looking abroad: In other countries where timber bridges are common, a positive feedback loop is present. Well-performing examples lead to greater confidence, more bridges being commissioned and built, and the knowledge, tools and culture to design, build and maintain them.

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Upskilling: Bringing in international consultants is one way to address the problem of inertia. However, the UK ‘building’ industry is experiencing a structural timber boom, proving that the knowledge, skills and supply chain to deliver similar structures are already growing in the UK. Whether domestically or internationally, sharing knowledge is a key to overcoming bias. Innovation requires investment and management of risk. Smaller-scale footbridges could be a good place to start, ideally in locations that are easy to inspect and maintain.

5 RIBA Journal, “Belgian Recypark turns refuse to reuse to make a circular economy at Anderlecht skatepark” published 15 January 2025. Available at: Belgian Recypark turns refuse to reuse to make a circular economy at Anderlecht skatepark (Accessed: 21 April 2026).

6 British Standards Institution, BS EN 1991-1-1:2025 Annex A – Eurocode 1: Actions on structures. Part 1-1: General actions, published 2025.

7 British Standards Institution, BS EN 14080:2013 – Timber structures. Glued laminated timber and glued solid timber – Requirements, published 2013.

8 British Standards Institution, BS EN 1993-1-1:2022 – Eurocode 3: Design of steel structures. Part 1-1: General rules and rules for buildings, published 2022.

9 British Standards Institution, BS EN 1992-1-1:2023 – Eurocode 2: Design of concrete structures. Part 1-1: General rules and rules for buildings, published 2023.

10 Bridge Design & Engineering Magazine, “Best of Both Worlds,” in Issue 121, published November 2025.

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3.1 Durability

Appendix A – Built Examples of this paper presents examples of timber bridges, both in the UK and internationally, with 120-year design lives, as well as historical examples that have already lasted longer.

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Unprotected vs protected: Whilst timber can achieve a 120-year design life11, key factors must be understood for it to reach its full potential. When considering longevity, a critical distinction should be made between unprotected and protected timber structures. Unprotected structures expose the timber to the elements and even with robust species and careful detailing, lead to shorter design lives in most climates. The upcoming revision of Eurocode 5 part 2 (EN 1995-2) defines different categories of timber bridges and their expected design lives.

Figure 5: Diagrammatic cross sections of protected timber structures

•

As illustrated in Eurocode 5 part 2, protected structures have separate components that shelter the structure from the elements. Traditional protection includes capping or cladding with timber shingles, weatherboarding, ceramic tiles or sheet metal. Much like buildings, these hard-wearing elements are the first line of defence and require special care when detailing. In these applications, treated timber or more durable species are often used. Relevant treatments can include chemical or thermal modification, regularly re-applied coatings or charring the outer surfaces. Even with treatment, one could expect to replace these elements several times over a bridge’s life, much like timber shingles or weatherboarding on a building. Detailing should anticipate this, promoting easy inspection and replacement.

•

When clearance requirements allow, modern bridges often inset the timber beams below a waterproof deck. A rule of thumb (in most climates) to define the projection of the protection beyond the timber is a 30° line from the bottom (most exposed) edge of the timber.

Figure 6: Diagrammatic cross sections illustrating the 30° rule

11 Note that the draft Timber Eurocode prEN 1995-2:2025, unmodified by the UK National Annex, provides design and detailing requirements to achieve 100-year design service life. A 100-year design life is standard for steel and concrete Eurocodes also, and is traditionally extended to 120-years under the UK National Annexes.

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Moisture management: Protection is important to preserving timber as it helps keep the moisture content within a suitable range. Whilst the focus (especially in the UK) should be ensuring the timber is not too wet too often, which can lead to warping, swelling and in the worst cases, rotting, the timber also should not get too dry, or it can be prone to cracking. Occasional moisture is acceptable if adequate air movement promotes thorough drying. Moisture sensors are gaining popularity in modern timber bridges, allowing conditions to be monitored remotely and for issues to be detected early. The revised Eurocode 5 suggests protected timber structures in Service Class 2 can tolerate an annual average moisture content up to 20%.

•

Splashing: Where timber is close to the ground or other horizontal surfaces, it is important to consider water splashing upwards onto the timber. Elevating or cladding at least the bottom 300mm of the structure helps prevent excessive moisture in the splash zone.

•

Species selection: Selection of timber species is a complex balancing act that considers durability, structural strength, aesthetics, availability, workability and susceptibility to pests. Ultimately, the choice may be particular to a given project. Species such as Spruce, Larch, Douglas Fir and Oak have a long history of use as structural timber in the UK. Newer, internationally sourced, modified timbers such as Accoya provide a long-lasting alternative. Coatings / treatments may also be considered to enhance durability although these alone do not constitute a ‘protected’ structure. They also increase the maintenance burden and if applied incorrectly they may trap moisture rather than repelling it.

3.2 Pests

Trees are often homes to insects, fungi and other organisms. Infestation of structural timber is a potential issue that can diminish performance resulting in failure.12 With this acknowledged, there are proven solutions to minimise this risk (these are linked to section 3.1 Durability).

•

Certain species are more resistant to infestation due to natural oils or high density.

•

Infestation of kiln-dried timber in a dry environment is very rare.

•

Timber treatments contain preservatives to deter insects and fungi.

•

As moisture creates an attractive environment for insects and fungi, keeping the timber relatively dry and allowing good air flow deters infestation.

•

Detailing should make regular inspection easy to ensure issues are identified and remedied early.

3.3 Highway spray

All bridge structures are susceptible to damage from de-icing salts / other chemicals contained within highway spray and runoff. Perhaps unique to timber, salt itself does not degrade its performance (which is why salt storage sheds are traditionally timber). However, if a bridge is poorly detailed, a build-up of salt may attract moisture to the area, not allowing it to dry properly. To avoid unsightly staining and potential salt buildup issues, any highway runoff should be directed away

12 The insect risks in the UK are Anobium punctatum (Common furniture beetle, commonly called ‘woodworm’) and in local areas of the South-East of England (as listed in the Approved Documents to the Building Regulations) Hylotrupes bajulus (House longhorn beetle). Termites tend to prefer warmer climates than the UK.

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from timber. This is often critical at bridge ends where bearings, drainage and movement joints interact. Proximity to highway spray should be a consideration of any structure supporting, above or adjacent to a highway (regardless of its materiality).

3.4 Fire

Fires may occur on, below or near any bridge due to vehicle fire, arson or nearby wildfire or industrial fires. As the majority of bridges are outdoors and unenclosed, the integrity of the structure is typically the main concern. Bridges forming part of a building or evacuation route will be subject to additional requirements as part of Building Regulations.

Timber reacts uniquely when burning. It produces a layer of char on the exterior which contributes to insulating the timber within, protecting it from heat and eventually preventing the timber from burning any further. The remaining cross-section of unburnt timber provides the new structural capacity of the element. Each species of timber has an associated rate of char, such that the fire performance can be designed for. When required, coatings are available that encourage the production of char and improve performance in a fire. Designing timber structures, including consideration of fire performance, is a well-documented process and is described fully in Eurocode 5, Part 1-2.

3.5 Slip resistance

Whilst this report focuses on structural timber, secondary elements such as decking, parapets, handrails and seating also require attention. Unfortunately, timber’s poor reputation with some bridge owners sometimes stems from bad experience with these secondary elements.

The considerations raised elsewhere (species selection, moisture management, detailing, etc) all apply to secondary elements. When exposed to the weather, these issues are even more critical. Where timber is used as decking, slip resistance is an important additional consideration. A plain timber plank is unlikely to provide sufficient slip resistance in wet weather. Grooves may increase resistance initially but often provide a location for water and dirt to collect. Slip resistant inserts are another alternative but may require extra maintenance. In all scenarios, understanding the environment and ensuring good drainage should be the priority. Timber boardwalks and decking on historic bridges are positive examples in a range of climates.

3.6 Timber repair

Like all materials, timber structures may be damaged due to fire, vehicle impact, or water (via failed protection). In these situations, it is possible to replace an entire timber element, or part of it.

•

For smaller elements, full replacement may be simpler. The use of mechanical fixings in construction simplifies this process.

•

For larger elements, partial replacement may be economical. Depending on the structural performance, timber specialists can remove an isolated area and splice in new material. This method is common in the preservation and restoration of historic timber buildings.

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Figure 7: Repairs made to a glulam beam struck by an oversized vehicle (image by Ingenieurbüro Miebach)

In all cases, bridge closure and temporary support may be necessary. The importance of detailing that allows easy inspection, maintenance and repair cannot be over-emphasised.

3.7 Costing

Another area where a lack of built examples, experience and confidence feeds uncertainty and perceived risk, is estimating the cost of timber bridges. Once this is overcome, the basic costs of structural timber are competitive, even when imported from mainland Europe. As indicated in section 2.7, the relatively light weight leads to savings in the size and cost of supports and foundations. Compared to more industrial materials, timber is an example where carbon and cost run parallel.

The cost of timber elements depends on size and species and always benefits from supplier input. Whether beams are straight, curved, curved in two directions or varying in cross section also affects cost as these traits influence the size of individual lamellas and the glue-up process. Beyond the beams, secondary elements are a big consideration with timber. Fortunately, proprietary fixings and cladding systems (designed for buildings) are available for consideration in cost plans.

When anticipating lifetime costs, inspection, maintenance and replacement of shorter life parts must be considered. This is not unique to timber bridges, although the layered nature of these structures demands special attention.

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3.8 Cautionary tales

There have been several cases in the last decade of timber bridges being removed prior to the end of their design life. 13 14 This has added to an understandable concern among clients about the longevity of timber construction. Investigations into causes 15 have generally pointed to poor detailing of connections and supports, causing long term water ingress and failure through fungal decay. Understanding of these critical elements has significantly improved in recent years, and typical details have changed. However, failures confirm the importance of competent specialist design and carefully monitored fabrication, alongside a comprehensive inspection and maintenance regime. It is important that clients, designers and builders continue to share experiences, learning from the good as well as the bad.

4 Timber bridges around the world

To develop the UK timber bridge industry we should look to other countries with strong timber cultures. Inspiration could include:

•

Studying built examples (see Appendix A)

•

Inviting international consultants to collaborate on UK projects

•

Reviewing design codes and guidance from other regions

Where design codes exist, they have evolved over time with input from relevant parties. While they do not hold the same legal weight when used out of jurisdiction, they hold clues to addressing all the challenges described previously. A few of the most relevant examples include:

Figure 18: Relevant design standards from other countries

13 Maidenhead Advertiser, “Jubilee River safety warning over ‘extremely dangerous’ collapsed footbridge,” published 3 July 2025. Available at: https://www.maidenhead-advertiser.co.uk/news/environment/202073/jubilee-river-safety-warning-over-extremely-dangerous-collapsed-footbridge.html (Accessed: 17 February 2026).

14 Environment Agency, “Thames Area Assets – Frequently Asked Questions (Temple Footbridge),” continuously updated page, last updated February 2026. Available at: https://engageenvironmentagency.uk.engagementhq.com/thames-area-assets/widgets/131458/faqs (Accessed: 17 February 2026).

15 Dorney Parish Council / AtkinsRéalis, “Ashford Lane Footbridge – Future Options Report (DOR-FP1),” published July 2024. Available at: https://dorneyparishcouncil.gov.uk/wp-content/uploads/2025/06/DOR-FP1-Ashford-Lane-FB-Future-Options-Report.pdf (Accessed: 17 February 2026).

Region

Standard

Timber bridge design approach

Canada

CSA S6 + CSA O86

Glulam, stress-laminated decks, high snow-load consideration

USA

AASHTO LRFD + NDS

Glulam, historic covered bridges, timber vehicle bridges

Europe

EN 1995-2 (Eurocode 5 – Part 2)

Engineered wood, national annexes, composite decks

Switzerland

EN 1995-2 + SIA 265

Covered bridges, high durability detailing

Germany

EN 1995-2 + DIN EN 1995-2/NA

Long-span glulam, stress-laminated decks

Austria

EN 1995-2 + ÖNORM B 1995-2

Modular timber-concrete systems, Alpine design conditions

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5 Conclusion

Despite its long history, structural timber is seldom chosen for contemporary bridges in the UK. While timber enjoys popularity in our ‘building’ sector, bridge owners and designers are reluctant to adopt this material, viewing it as inferior to industrial alternatives (steel and concrete). Ironically, by being less industrial (naturally occurring), timber has unique potential to support our quest for a lower-carbon future.

The advantages of structural timber are numerous. In addition to being renewable, it stores carbon, it is easy to work with and it supports local and regional supply chains. It has a good strength-to-weight ratio, and modern engineered timber is both structurally quantifiable and economical.

To gain the confidence needed for a positive feedback loop (build, learn, commission, and repeat) we must become comfortable with the challenges inherent in this natural material. Durability is rightly the focus of timber sceptics, yet our peers in similarly wet countries with stronger timber cultures routinely demonstrate that with proper specification, detailing, and maintenance, a protected timber structure should last as long as the steel or concrete alternative.

While not intended as a standalone technical guide, this paper serves as a departure point for those interested in timber. As our experience and knowledge of this subject expand, we anticipate this paper evolving with further input from readers and colleagues. Once we embrace this material, we can exploit its potential: building efficiently, robustly, economically and sustainably.

6 Contributors

Net Zero Bridges Task Group on Timber Bridges: Ezra Groskin (Moxon Architects, task group chair), Brian Duguid (Mott MacDonald), David Knight (Cake Engineering), Giacomo Mauriello (Hardesty & Hanover), Paul van Hagen (Hardesty & Hanover), Richard Thebridge (Moxon Architects), Solene Fercocq (Arup), Stephen James (Stephen James Architects).

7 Technical Reviewers

We are grateful to our technical reviewers whose research and work inspired this paper. Their feedback was generous and instrumental in refining the content: Will Hawkins (Bath University), Frank Miebach, Dominik Niewerth and Lukas Osterloff (Ingenieurbüro Miebach), Oscar Emanuel (Xylotek), Camille Chevrier (Format Engineers).

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Appendix A – Built Examples

Whether in the UK or elsewhere, existing bridges are the best evidence of timber’s effectiveness. Learning from good (and bad) examples is the key to an evolving industry. Photographs, drawings, details and specifications are evidence of overcoming technical challenges. Visiting a bridge in person is best for experiencing the unique character of a timber structure.

The following list highlights some of the better-known timber bridges in the UK and beyond. It is by no means exhaustive, nor does it represent the entire range of possibilities that structural timber presents.

UK timber bridge examples

Mathematical Bridge Cambridge

1749, 1866, 1905

15m truss / arch

Sophisticated design. Engineering landmark link

Barmouth Viaduct Barmouth, Mawddach Estuary, Gwynedd

1867, 1906-8

5.5m spans, 700m timber trestle

Grade II listed. Longest timber bridge, and oldest in regular use in Britain

Dutton Horse Bridge

River Weaver, between Northwich and Runcorn

1919

31m arch

One of earliest surviving laminated timber bridges

Black Dog Hill Bridge

Chippenham, Wiltshire

1999 34m glulam redwood timber arch

45m total length

Award-winning Millennium Bridge, part of Sustrans network

Luss Footbridge

Luss, Loch Lomond

1980s

20m arch

40m total length

Arched footbridge over the A82

Far Moor Bridge

Ribblehead, Yorkshire

2011

24m arch, 15m end spans

Active travel and Bridleway bridge with stress-laminated arches, screw-laminated deck

Westonbirt Treetop Walkway Tetbury, Gloucestershire

2016 10.5m spans, 284m total length

Longest raised walkway in UK. Timber/steel composite structure

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International timber bridge examples

Horai Bridge

Shimada City, Japan

1987 10m span beam bridge, 900m total length

Longest timber pedestrian bridge in the world

Flisa Bridge Hedmark, Norway

2003 Glulam truss, 70m longest span, 196m total length

World’s longest timber bridge designed for full traffic loads (in 2005)

Kjøllsæter Bridge Rena River, Norway

2006 Glulam truss, 45m longest span, 158m total length

Designed to carry military vehicles up to 109T. ‘World’s strongest timber bridge’

Anaklia-Ganmukhuri Pedestrian Bridge

Anaklia/Ganmukhuri, Georgia

2012 Glulam truss cable stayed, 84m max span, 505m total length

Europe’s longest timber bridge

Nancy Pauw Bridge

Banff, Alberta, Canada

2022

Cantilever / shallow arch, 80m span

Winner, IStructE Supreme Award for Structural Excellence, Structural Award 2025

Balingen Parkufersteg

Baden-Württemberg, German

2023

Timber trough / through girder, 41m span

Exemplar of sustainable infrastructure

Timber Bridge Manhattan, New York

2023

Two span warren truss, 92m total length

Large scale urban intervention. Connects High Line to Penn Station in NYC

Rathausbrücke

Tuttlingen, Germany

2024 Concrete composite glulam girder, 17m main span, 55m total length

Winner of Footbridge Award 2025, Short Span

RO Timber Bike and Footbridge F29K Brussels, Belgium

2024 Box girder covered bridge, 67.5m span

Innovative modern covered bridge

Passerelle a Chevenon Chevenon, France

2024

Cantilever / beam, 30m span

Winner, Sustainability Award, Footbridge 2025

Passerelle Zwolle Zwolle, Netherlands

2025 Five span beam, 34m max span, 130m total length

Recently opened Greened Station Bridge

Timber durability classes are used to describe how resistant different types of wood are to decay and insect attack, especially when exposed to outdoor conditions. These classes are standardized in EN 350 and EN 335, and they help guide decisions for construction, landscaping, and furniture making.

Durability Class 1 – Very Durable

• Resistance: Highly resistant to decay and insect attack.

• Typical Lifespan (in ground contact): More than 25 years.

• Use Cases: Marine applications, decking, outdoor furniture, heavy-duty structures.

Durability Class 2 – Durable

• Resistance: Good resistance to decay and insects.

• Typical Lifespan: 15–25 years.

• Use Cases: Exterior cladding, garden structures, joinery.

Durability Class 3 – Moderately Durable

• Resistance: Moderate resistance; may need treatment for long-term outdoor use.

• Typical Lifespan: 10–15 years.

• Use Cases: Fencing, sheds, treated outdoor furniture.

Durability Class 4 – Slightly Durable

• Resistance: Low resistance; not suitable for ground contact without treatment.

• Typical Lifespan: 5–10 years.

• Use Cases: Indoor use, or outdoor use with preservative treatment.

Durability Class 5 – Not Durable

• Resistance: Very low resistance to decay and insects.

• Typical Lifespan: Less than 5 years (untreated).

• Use Cases: Only suitable for indoor use unless treated.

  At Vandecasteele Houtimport, we stock a wide range of certified timber species across various durability classes, providing suitable solutions for virtually every timber application.

THERMO ASH – Technical datasheet

(based on information we received from our suppliers)

• Thermo Ash is produced only with the help of high temperature and steam.

• It retains its natural properties in an highly improved form after the treatment.

• The quality of the product is guaranteed due diligence of the raw material selection. Only European Ash is used.

• Thermo Ash from Vandecasteele is according to EN 350 in the durability class 2.

• Due to the fact that wood is a natural product, a diversification within the several planks can occur.

Test methods:

• Each test has its own test parameters, but in general one can say, that the tests were carried out at 20 °C and a relative humidity of 65 %.

• The tests were implemented according to the requirement of the respective test standard.

• The tests were carried out by an independent research institute.

download the technical datasheet

THERMO TREATED AYOUS – Technical Datasheet

(based on information we received from our suppliers)

• Treatment Class : THERMO D

D stands for durability; the wood has a darker brown tone. Its durability and stability are improved significantly. The wood is thermally modified at

212°C and is suitable for internal and external applications without the need for chemical preservative treatment. The Thermo treated wood is

also suitable for humid spaces like spa and sauna.

• Dimensional stability

Lowered equilibrium moisture content of the Thermo treated wood makes it dimensionally stable and the material retains its shape far better than

untreated wood. The outstanding dimensional stability allows the Thermo treated wood to be successfully used in all climates and even in hot

and humid weather conditions indoors and outdoors.

• Use Class

Thermo treated Ayous is suitable for use class 3 (BS EN 335)

The wood is above ground and exposed to the weather (suitable for cladding, rainscreen, decking,..).

Not recommended for use in direct contact with the ground.

• Durability

Thermo treated Ayous is classified as durability class 2 (BS EN 350)

• Termite resistant

Thermo treated Ayous is not termite resistant. It can be treated with specialist termite chemical treatments.

• Fire Rating

Thermo treated Ayous has D4 rating which means same as any natural timber.

• Wearing over time

Like all timber products, Thermo treated Ayous will go grey upon exposure to UV, and in time may show some fine cracks or splits on the surface.

The graying effect will be visible in a relatively short period of time, 3 to 6 months after installation. It is recommended to apply an oil or wood coating to help preserve and maintain the original appearance

Download the data sheet here

THERMO TREATED FRAKE – Technical Datasheet

(based on information we received from our suppliers)

Treatment Class : THERMO D D stands for durability; the wood has a darker brown tone. Its durability and stability are improved significantly. The wood is thermally modified at 212°C and is suitable for internal and external applications without the need for chemical preservative treatment. The Thermo treated wood is also suitable for humid spaces like spa and sauna.

Dimensional stability Lowered equilibrium moisture content of the Thermo treated wood makes it dimensionally stable and the material retains its shape far better than untreated wood. The outstanding dimensional stability allows the Thermo treated wood to be successfully used in all climates and even in hot and humid weather conditions indoors and outdoors.

Use Class Thermo treated Frake is suitable for use class 3 (BS EN 335) The wood is above ground and exposed to the weather (suitable for cladding, rainscreen, decking,..). Not recommended for use in direct contact with the ground.

Durability Thermo treated Frake is classified as durability class 1 (BS EN 350)

Termite resistant Thermo treated Frake is not termite resistant. It can be treated with specialist termite chemical treatments.

Fire Rating Thermo treated Frake has a D-S3 rating which means same as any natural timber.

Wearing over time Like all timber products, Thermo treated Frake will go grey upon exposure to UV, and in time may show some fine cracks or splits on the surface. The graying effect will be visible in a relatively short period of time, 3 to 6 months after installation. It is recommended to apply an oil or wood coating to help preserve and maintain the original appearance.

Download the technical datasheet here

Thermo Spruce and Pine – Technical datasheet

(based on information we received from our suppliers)

• Treatment Class : THERMO D

D stands for durability; the wood has a darker brow tone. Its durability and stability are improved significantly. The wood is thermally modified at 212°C and is suitable for internal and external applications without the need for chemical preservative treatment. The Thermo treated wood is also suitable for humid spaces like spa and sauna.

• Dimensional stability

Lowered equilibrium moisture content of the Thermo treated wood makes it dimensionally stable and the material retains it shape far better than untreated wood. The outstanding dimensional stability allows the Thermo treated wood to be successfully used in all climates and even in hot and humid weather conditions indoors and outdoors.

• Use Class

Thermo treated Spruce and Pine is suitable for use class 3 (BS EN 335)

The wood is above ground and exposed to the weather (suitable for cladding, rainscreen, decking,..).

Not recommended for use in direct contact with the ground.

• Durability

Thermo treated Spruce and Pine is classified as durability class 2 (BS EN 350)

• Termite resistant

Thermo treated Spruce and Pine is not termite resistant. It can be treated with specialist termite chemical treatments.

• Fire Rating

Thermo treated Spruce and Pine has D4 rating which means same as any natural timber.

• Wearing over time

Like all timber products, Thermo treated Spruce and Pine will go grey upon exposure to UV, and in time may show some fine cracks or splits on

the surface. The graying effect will be visible in a relatively short period of time, 3 to 6 months after installation. It is recommended to apply an oil or wood coating to help preserve and maintain the original appearance

Download the technical file here

We don’t trade wood featuring on the list of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

By preference we buy exclusively certified timber that complies with the major international third party verification schemes:

1. Forest Stewardship Council (FSC)

2. Program for the endorsement of Forest Certification (PEFC)

3. Origine et Légalité des bois (OLB)

4. NEPcon LEGAL SOURCE standard.

We ensure European standards compliant due diligence (EUTR/FLEGT):

1.  We undertake field visits at forest management units and/or

2. We perform yearly audits on suppliers

3. We use satellite data, information gathered from GPS loggers and digital fingerprints

We permanently investigate the latest traceability technologies such as Block chain and advanced Digital fingerprint recognition.

Where feasible, commercial partners assist by conducting the checking and verification of documents.

We verify compliance with the applicable legislation in the country of harvest through independent audits

In 2019 Vandecasteele has appointed a local Sustainability Field Supervisor in Brazil.

• Complying with all major international certification standards, we permanently promote sustainable forest Management (SFM). This safeguards the preservation of forests, protects biodiversity, combats deforestation and illegal logging and halts the loss and degradation of forest ecosystems.

• By responsibly trading wood, we preserve sustainable managed forests that are carbon neutral: the amount of carbon that can be released as a result of harvesting is equal to or smaller than the amount taken from the atmosphere.

• We actively promote the responsible usage of wood as the most environmental friendly construction and production material as eco-friendly substitutes to less sustainable materials such as steel or concrete. 

• We also trade a large range of lesser commercially known species that might otherwise miss their environmental value: 33 different species from African forests, 32 different species from South-American forests.

• In comparison with many other timber traders, we also accept to trade all dimensions of the wood harvested from a log to minimize the waste of unused wood that does not comply with standard commercial dimensions.

• We keep stock for our customers, so our supplier can optimize the production and the transport to Europe in one go.

• In order to pro-actively protect the environmental value of tropical wood from 2019 Vandecasteele has appointed a local Sustainability Field Supervisor in Brazil.

• In the long run, local communities worldwide surely depend on the environmental AND economic value of their forests if these latter are sustainably managed.

• In the short run however, the main cause of deforestation is actually not the harvesting of wood but agricultural expansion. This has a pure economic reason. The benefits of one hectare of palm oil, soy plantation, or cattle breeding outweigh the long-term economic value of the forest.

• However, harvesting trees in well-managed forests directly reduces the opportunity costs of not converting forests to plantations. At the same time this secures the long term economic value of the forest as a secure bank account for local populations. This by guaranteeing healthy forests that will perpetuate harvesting and thus recurrent income. This can only be achieved if sustainable harvesting rotation cycles, sustainable forest inventory management and selective cutting standards of commercial species are being respected.

Link to the technical data sheets

Les arbres d'afrique centrale Tome I Familles de A à F

The R-value (thermal resistance) of for example Padouk wood depends on the thickness of the material and its lambda value (λ), which is the thermal conductivity.

According to the technical datasheet, Padouk has a lambda value of 0.18 W/m·K.

R-value Calculation

The formula to calculate the R-value is:

R=dλR=λd​

Where:

• d = thickness in meters

• λ = thermal conductivity in W/m·K

For Padouk with a thickness of 14 mm (0.014 m):

R=0.0140.18≈0.078 m2⋅K/WR=0.180.014​≈0.078m2⋅K/W

Padouk vs Other Wood Types

Padouk has a thermal conductivity (lambda value) of about 0.18 W/m·K. This is typical for tropical hardwoods.

For a thickness of 14 mm (0.014 m), the thermal resistance (R-value) is:

R=0.0140.18≈0.078 m2⋅K/WR=0.180.014​≈0.078m2⋅K/W

Other wood types:

• Softwoods (e.g., pine, spruce): λ ≈ 0.13–0.14 → R ≈ 0.10

• Oak: λ ≈ 0.16 → R ≈ 0.088

Summary: Padouk insulates slightly less than softwoods, but the difference is minor. Wood is generally not used for insulation but for structure and aesthetics.

• As a socially responsible company, Vandecasteele aligns with international best practices, such as the standards set out by the United Nation’s Sustainable Development Goals. Wherever possible, our audits also include a check whether our suppliers respect the core ILO conventions, ILO Code of Practice Safety and Health in Forestry work, the UN Declaration on the Rights of Indigenous People, and the United Declaration on Human rights.

• Vandecasteele is committed to extending these international best practices to all of its sourcing and suppliers.

Vandecasteele is committed to source 100% from certified suppliers by 2025.

The use of wood as an alternative to other materials, particularly in construction, contributes to reduce human climate impact even further. Adapting material choices, designs and production processes to the new conditions is a major challenge for the construction sector. Greater use of wood-based products and wooden structures is a significant part of the solution, thanks to the material’s carbon storage and substitution effects.

The forest gains its vitality from the sun. Through photosynthesis, solar energy is absorbed and reacts with carbon dioxide to produce nutrients for the growing trees.
The forest’s products contain carbon that has been absorbed by the trees in the form of carbon dioxide: wood captures CO²

 Photosynthesis, the world’s most vital formula

6H2O + 6CO² + solar energy > C6H12O6 + 6O² Water carbon dioxide > glucose + oxygen

We adhere to the European timber regulation 995/2010 (EUTR) that came into force in 2013 prohibiting placing illegally harvested timber on the European market.

The regulation is a major part of the EU’s effort to reduce deforestation and protect at risk tree species as part of the EU Forest, Law, Enforcement, Governance and Trade (FLEGT) Action Plan.

To ensure a EUTR/FLEGT compliant due diligence process we carry out self-conducted audits on a permanent basis:

1. We undertake field visits at forest management units and/or

2. We perform yearly audits on suppliers

3. We use satellite data, information gathered from GPS loggers and digital fingerprints

4. We permanently investigate the latest traceability technologies such as Block chain and advanced Digital fingerprint recognition.

We run a company wide sensitization policy to buy predominantly certified timber that complies with third party verification schemes such as FSC (Forest Stewardship Council), PEFC (Program for the endorsement of Forest Certification), OLB (Origine et Légalité des bois) and the NEPcon LEGAL SOURCE standard.

Our FSC – PEFC commitment results in the following scores:

1.    Softwoods: 100% FSC® or PEFC

2.    Tropical hardwoods: 95% FSC- PEFC – 3RD party certified.

We ensure European standard compliant due diligence (EUTR/FLEGT):

1. We undertake field visits at forest management units and/or

2. We perform yearly audits on suppliers

3. We use satellite data, information gathered from GPS loggers and digital fingerprints

4. We permanently investigate the latest traceability technologies such as Block chain and advanced Digital fingerprint recognition

Where feasible, commercial partners assist by conducting the checking and verification of documents throughout the entire supply chain.

We verify compliance with the applicable legislation in the country of harvest AND any processing country along the supply chain through independent audits.

In 2019 Vandecasteele has appointed a local Sustainability Field Supervisor in Brazil.

We have a sustainability management team in charge of all sustainability topics in our company.

GRI standards reporting – we keep all our data for at least 5 years – on basis of these figures we manage our action plan for the next year.

• We take our responsibility very seriously when placing timber or timber products on the EU market by gathering information about the products we source, asses the risk of non-compliance with applicable legislation and trade legislation and include risk mitigation measures.

• We guarantee to have an in-house developed due diligence system in place, audited by external consultants with a framework of procedures and processes to ensure the timber we place on the EU market has a legal provenance.

• As a part of our DDS system we have a publicly available company policy that includes a commitment to comply with all relevant legal requirements. Discover our Vandecasteele Timber Responsible Sourcing Policy here.

• We have a large stock of certified and 3rd party verified legal timber which is the best proof of compliance within the EU Timber regulation and progressively increase our volumes in certified timber.

• As a company target we aim to source 100 % certified timber only by 2025. Our DDS system is an ongoing process and is constantly evaluated to have it as robust as possible and according to the latest legal requirements.

The purchasing department supervised by the senior management team.

Due diligence is conducted, at least every 12 months to verify that applicable legislation is complied with.

1. Healthcare – FSC supports the healthcare for local communities

2. Education – Habbekrats – woodworker education – beekeeper education

3.  Agriculture, farming, and fishing – We support local agriculture

4.  Road infrastructures – We have built our own roads – a cycling path and sidewalk next to our company, our own access road.

5.  Water supply – we have our own water reservoirs which have various purposes: collecting water, prevent flooding, emergency support to farmers in times of drought and last but not least, it is beautifully integrated in the environment.

6.  Forestry Management – all projects FSC , PEFC and OLB we strongly support by buying certified timber.

7.  Any other activities to generate revenues – de Warmste Week , Belgium’s most successful end of year Charity Program – Habbekrats – every year we choose a new project which we finance and support with our whole team.

Read more

Please read here our EUDR info letter here

Big changes and promising beginnings

Small steps towards a better world

Forests play a crucial role in maintaining our climate, preserving biodiversity, and supporting the well-being of people globally. To safeguard these vital ecosystems, the European Union has mandated since 2013, under the EU Timber Regulation (EUTR), that only legally harvested timber can be placed on the EU market. Starting December 30, 2025, this regulation will be enhanced by the new EU Deforestation Regulation (EUDR). This new framework not only requires timber to be legally sourced but also ensures it is deforestation-free and fully traceable to its specific origin.

The EUTR obliges operators to establish a due diligence system comprising three key components: information collection, risk assessment, and risk mitigation.

With the EUDR, this system will be further developed to include mandatory geolocation at the plot level, the use of satellite data, and the submission of a due diligence statement via a new EU information system.

Small steps towards a better world

At Vandecasteele Houtimport, we have taken responsibility on-site for many years. We have adhered to the EU Timber Regulation (EUTR) since 2013, and our due diligence policy has been fully integrated into all our operations. We prioritize certified wood (FSC®-C018601, PEFC/07-32-04, OLB, TLV, Preferred by Nature), ensuring that its origin is rigorously verified for legality and responsible forest management. This approach helps us minimize risks in the source country and facilitates compliance with the new EU Deforestation Regulation (EUDR).

We collaborate with external auditors and employ our own forest engineer to inspect purchases from Latin America on-site. Our compliance team diligently monitors all matters related to CITES, FLEGT, EUTR, EUDR, and other standards daily.

Starting December 30, 2025, our invoices will feature TRACES verification numbers, demonstrating our commitment to transparency. As our customer, you can rest assured that we handle the entire process. All our certificates and our sustainability report are available on our website.

Balance between trade and regulation

TRACES verification will be central to the EUDR process. Before placing wood products on the EU market, each operator must submit a due diligence declaration via the European Commission’s information system. This declaration must include the exact geographical coordinates of the felling area, the date of harvest, and confirmation of deforestation-free production. Without a TRACES-ID, sales within the EU are prohibited.

The new rules will enhance supply chain transparency by requiring companies to provide detailed information on the timbers origin, harvesting methods, legality, and any potential risks of deforestation or human rights violations. Each product will receive a TRACES verification number. At Vandecasteele Houtimport, we blend external expertise with in-depth regulatory knowledge and a forward-thinking approach. We are your trusted partner.

Goals with a clear direction

At Vandecasteele Houtimport, we exceed legal requirements by taking responsibility for the planet, human rights, and fair trade. We believe that companies should lead the way in transitioning to a sustainable economy.

We deliberately choose certified timber, ensure transparency throughout the supply chain, and collaborate with partners who share our vision. We are proud to be the first timber company globally to receive UNITAR certification from CIFAL FLANDERS as an ‘SDG Pioneer’ and ‘SDG Champion’.

Additionally, we are members of the Voka Charter Sustainable Business, actively committing to the 17 United Nations Sustainable Development Goals. Each year, we launch new initiatives to continually enhance our impact.

Buying from a responsible supplier makes you a responsible buyer.

Latest developments on the EU Deforestation Regulation (EUDR) – 4.05.2026

What has been decided?

On 4 May 2026, the European Commission published its official EUDR simplification package, in implementation of Article 34(1a) of Regulation (EU) 2023/1115.

This package aims to simplify the application of the EUDR, without undermining the core requirements of the regulation.

Simplification of due diligence:

• Only the first operator placing the product on the EU market is required to submit a due diligence statement.

• Only the first downstream operator in the supply chain must retain the reference number of that statement.

Important: the European Commission confirms that the date of entry into force remains unchanged (end of 2026).

What does this mean for Vandecasteele Houtimport and our customers?
At Vandecasteele Houtimport, we take all necessary measures to comply with due diligence and traceability requirements, ensuring our customers can trust the wood products we supply.

To guarantee the quality of our internal processes, we commissioned an independent audit by Preferred by Nature.
With our Preferred by Nature Chain of Custody certification, you can be confident that our procedures have been thoroughly assessed and found compliant by an external party.

We prioritise certified wood, ensuring its origin is rigorously verified for legality and responsible forest management.
Vandecasteele Houtimport holds a wide range of certifications, including FSC™, PEFC, OLB, and LegalSource (managed under PBNC Chain of Custody controls).
Preferred by Nature certification helps us identify and mitigate risks in our supply chain while supporting compliance with the EU Deforestation Regulation.

Our 25-year commitment to the VOKA Charter for Sustainable Entrepreneurship, guided by the UN’s 17 Sustainable Development Goals, has shaped Vandecasteele Houtimport into a sustainability-driven company and laid the foundation for our recent Preferred by Nature certification.

We closely monitor developments and will update this page as soon as new decisions are made.

Commission FAQ

Guidance Document for the Regulation on Deforestation-Free Products (2026)

EUDR supply chain infographics (3rd edition)

Deforestation law: Parliament adopts changes to postpone and simplify measures

EU deforestation law: Council and Parliament reach a deal on targeted revision

EU deforestation law: Parliament supports simplification measures

Proposal EU Commission

EU Regulation

Commission's Guidance Document

Commission FAQ

Implementation of the UE Deforestation Regulation

EU TRACES

Listing of Padouk, Afzelia, Khaya, Ipé and Cumaru under CITES provides additional assurance of sustainable origin.

CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) is an international agreement aimed at regulating trade in endangered plant and animal species. Species protected by CITES are classified into different appendices (I, II, and III), depending on the level of protection required. The appendix in which a species is listed determines whether international trade is allowed and under what conditions.

New timber species added to CITES Appendix II

The timber species Afrormosia (Pericopsis spp.) has been listed in Appendix II of CITES since 1992. It is evident that trade in this popular species has seen a positive evolution in recent years, partly thanks to this regulation concerning sustainable and legal origin.

During the CITES CoP19 in November 2022, it was decided to additionally list the African populations of Doussie (Afzelia spp.), Khaya Mahogany (Khaya spp.), and Padouk (Pterocarpus spp.) in Appendix II, effective from 23/02/2023.
From 23/11/2024, the South American timber species Ipê (Handroanthus spp., Roseodendron spp., and Tabebuia spp.) and Cumaru (Dipteryx spp.) will also be listed in Appendix II.

These species are listed with annotation #17: only logs (HS code 44.03), sawn wood (HS codes 44.06, 44.07), veneer (HS code 44.08), laminated wood (HS codes 44.12.13, 44.12.14, and 44.22), and processed wood (HS code 44.09) are protected.

What does listing in CITES Appendix II mean?

Appendix II includes species that are not necessarily threatened with extinction but whose trade must be regulated to prevent overexploitation. In some cases, not all species within a genus are endangered, but only specific ones in certain growth areas. In such cases, CITES opts to list the entire group to practically organize regulation and controls.

Every import, export, and re-export of species listed under Appendix II must be accompanied by the necessary permits. These permits are usually issued based on export quotas per producing country. These quotas are based on scientific studies to ensure legal, traceable, and above all, sustainable exploitation.

https://www.fedustria.be/projecten/cites

What species are requested to have CITES export documents when re-exported out of the EU?

Afrormosia - Afzelia Doussié Bipidensis - Ipé - Cumaru and Padouk

• Since 2000 we committed ourselves to integrate sustainability in our daily operations by signing the West Flanders Corporate Sustainability Charter, committing to environmental objectives exceeding applicable environmental legislation.

• We want to prove that we are considerate and efficient, without benefiting from exploitation or taking advantage of natural resources. The Charter is a management tool and is based on the 5“P” s  Planet - People –Prosperity - Partnership and Peace. Vandecasteele Houtimport is committed to continuously improve performances on all levels.

• We have realized 540 sustainability actions in 10 relevant themes since the year 2000.  Charter themes focus on 10 topics including management  of  energy , water, waste, pollution, noise and packaging.   Also, the environmental integration of the company, people management etc. all relevant to our business.

• Since 2018, the Charter has undergone a serious face lift.  The Chamber of Commerce has changed the name into "Voka Corporate sustainability Charter".  The new charter is based on the 17 Sustainable Development Goals of the United Nations.  Companies who have participated over 3 years and who have incorporated the 17 Sustainability Goals of the United Nations into their daily activities, will receive the UNITAR certificate (United Nations Institute for Training and Research). In 2020, we have earned our "SDG-Pioneer" certificate.

• In 2022 we obtained our SDG Champion Award from the United Nations

• In 2025 we obtained our SDG Champion Award from the United Nations

• Our action plan for 2019-2020:

  SDG 1: Corporate governance – identifying risks of human rights.

  SDG 4: Social engagement – Cooperation with schools and universities – WOOD FOR LIFE

  SDG 5: People management - hiring people on basis of their skills and competence and not gender.

  SDG 6: Quality of our environment – biodegradable wastewater management.

  SDG 9: Durable logistics – Investment in electronic battery charger for cars.

  SDG 11: Risk control – Cyber attack proof company

  SDG 14: Cradle to cradle management – no more plastic in our timber packaging

  SDG 15: Climate change and energy – Tackle climate – use WOOD.

  SDG 16: Durable investments and purchasing - Bringing new technologies into our Due diligence

  SDG 16: Communication and dialogue – 100@PARIS

• This is an ongoing process.  Our people attend conferences, meetings, fairs, webinars, and expert groups to train themselves and their colleagues on a permanent basis, sharing all relevant updates via a performing intranet and quarterly information sharing sessions.

• We want resilient people who pro-actively face the future sustainability challenges in the timber trade industry.

A lack of information and misinformation remain a big challenge. Therefore, we are investing in 100 % traceability and transparency with the help of new technology such as Digital Fingerprints and Block chain technology.

Our team is fully committed to systematically gather and document all information required to guarantee that the international certification standards are respected or even exceeded throughout the entire supply chain.

We appointed a local Sustainability Field Supervisor in Brazil to conduct field audits and CoC verification. 

We have obtained our "SDG Pioneer" Certificate in October 2020 and we also signed The Pledge of the United Nations.

Defining Success Across Generations

We, a global community of family businesses, commit to build a sustainable future across generations.

Family businesses contribute meaningfully to both economic growth and employment and have the potential to create a more purpose-driven model of business. With our inherent focus on long-term success and responsible ownership, we strive to apply our entrepreneurial know-how and resources to build a just and equitable world, where our planet will flourish across generations. The Sustainable Development Goals (SDGs) provide family businesses with opportunities to create a shared prosperity for all. We commit to taking action on the SDGs by advocating for and upholding the following principles:

• Sustainable Growth: To promote and model business practices and investments that will enable sustainable economic growth and deliver long-term value creation for all present and future stakeholders

• Environmental Stewardship: To have a positive long-term impact by taking urgent action on climate change, enabling sustainable production and consumption, and advancing the responsible use of natural resources.

• Social Inclusion: To promote inclusive practices in our communities and beyond, including gender equality, diversity and decent work, to ensure that both current and future generations attain dignity and fulfil their potential.

• Good Governance: To establish sound family and corporate governance structures that are transparent, inclusive and accountable to stakeholders; to ensure compliance with ethical and corruption-free business practices.

In partnership with United Nations (UNCTAD), we will track our progress and assess the impact of our pledge in a transparent manner, using a common set of performance indicators.

We invite you to act now and join us in creating a shared prosperity. Together we will build a sustainable future and define success across generations.

27 April 2020

The tropical timber arrives free from plastic packaging. 
The timber crates are 100% re-usable. 
Some of the Scandinavian Softwood still arrives plastic wrapped. We are persuading our suppliers NOT to use plastic wrapping any more, rather to use paper or nothing at all. 
When plastic wrappings arrive in our company, we remove it and re-use it. Eventually, the plastic foil is collected in a container for recycling locally.
Particle or dust waste is collected and sent for recycling.
Metal waste is a precious resource, and therefore also recycled locally.

Our main energy consumption consists of LED lighting for which the energy is maximally produced by our own solar panels. The energy of the trucks and side loaders is diesel.  All engines are complying with the highest EURO standard. 

We purchase our timber in big quantities and in a variety of species and sizes. This allows us to reduce transport and handling costs.

We strive to obtain gender equality at all levels. We hire people based on their skills and competences without gender preference.  Besides near gender equality within  all our management, office and sales team, we have one female truck driver and strive to continue to raise gender equality. Through our commitment to the Durability Charter, since 2000, we are integrating the 17 SDG's in our daily activities.

FSC certified timber contributes to the local communities by providing education, health care and housing, …. We are promoting certified timber, especially FSC certified timber. Our goal is to trade only certified timber by 2025.

Of course, we are not only legally bound to, but also fully committed to give notice of any infringement of international legislation/certification standards. We keep record of all disputes and remedial actions we encounter. We take appropriate action and we document our actions and their effectiveness. In addition, designated staff records the process of handling a dispute, including the investigation process and decision.