Timber Merchants

We stock a range of different timber for various applications, but some of our most popular categories are:

• Structural Timber - such as C16 and C24 graded timber
• CLS Timber - for studwork, partitioning and more. (Read: What is CLS Timber?)
• Decking Timber - for building outdoor decking, treated against the elements.
• Roofing batten
• Fencing and Garden supplies.

Structural Timber

Our structural timber is strength graded and perfect for load-bearing applications in construction projects:

• C16 Timber - Kiln dried regularised joists ideal for general construction (47x75mm)
• C24 Timber - Higher-grade regularised sawn joists for more demanding structural applications
• Multiple Sizes - Available in various dimensions from 2x2 (47x50mm) through to 8x2 (47x200mm)
• Length Options - Choose from standard 2.4m lengths up to longer spans for specific requirements

All our structural timber is kiln-dried to ensure dimensional stability and consistent performance in your construction projects.

CLS Timber

Canadian Lumber Standard (CLS) timber is specially prepared for internal studwork and framing:

• Planed All Round - Smooth finish with rounded edges for easy handling
• Kiln Dried - Superior stability and straightness
• Common Sizes - 3x2 (38x63mm) and 4x2 (38x89mm) for standard stud walling
• Standard Length - 2.4m to match common ceiling heights
• C16 Graded - Suitable for load-bearing applications

CLS timber is the ideal choice for internal partitioning, stud walls, and other indoor framing projects where a neat, consistent finish is important.

Treated Timber

For outdoor applications and areas exposed to moisture, our pressure-treated timber provides long-lasting protection:

• C16 and C24 Options - Available in both strength grades to suit different applications
• Regularised Finish - Clean, consistent dimensions
• Green or Brown Treatment - Choose the colour that best matches your project
• Multiple Sizes - From 2x2 (47x50mm) through to 8x2 (47x200mm)
• Various Lengths - 2.4m, 3.0m, 3.6m, and custom lengths available

The treatment process protects against rot, fungal attack, and insect infestation, significantly extending the service life of outdoor timber structures.

Roofing Battens

Our range of roofing battens includes both standard treated battens and graded battens certified to BS 5534 standards:

• 25x38mm Battens - Standard size for typical roofing applications
• 25x50mm Battens - Wider profile for increased strength
• BS 5534 Graded Options - Specifically tested and certified for roofing applications
• 4.8m Lengths - Standard size for efficient coverage
• Pressure Treated - Protected against moisture and biological attack

BS 5534 graded battens are specifically tested to ensure they meet the strength and performance requirements for roof constructions, providing peace of mind for critical applications.

Fencing Timber

Create durable garden boundaries with our comprehensive range of fencing timber:

• Fence Posts - Available in 3x3 (75x75mm) and 4x4 (100x100mm) sizes
• Arris Rails - 3x3 (75x75mm) for sturdy fence construction
• Gravel Boards - 22x100mm and 22x150mm treated options to protect fence panels from ground contact
• Brown or Green Treatment - Choose your preferred aesthetic
• Multiple Lengths - Standard sizes from 1.8m to 3.0m
• Pointed Timber Pegs - 47x50x600mm for ground anchoring

All our fencing timber is pressure treated to ensure it stands up to the challenging British weather, providing years of reliable service.

Decking Timber

Create beautiful outdoor living spaces with our quality decking boards:

• 32x125mm (Finished Size 26x118mm) - Standard decking boards
• 32x150mm (Finished Size 26x141mm) - Wider boards for a premium look
• Pressure Treated - Protected against rot and fungal attack
• Multiple Lengths - 2.4m, 3.6m, and 4.8m options
• Smooth Finish - Comfortable for barefoot use

Our decking timber is specially selected for its appearance and durability, with pressure treatment ensuring it withstands the elements year after year.

Cladding Timber

Add character and protection to exterior walls with our timber cladding options:

• 19x125mm Shiplap Weatherboard - Classic overlapping profile for excellent weather protection
• Pressure Treated - Enhanced resistance to moisture and biological attack
• Sold Per Metre - Order exactly what you need for your project

Timber cladding provides both aesthetic appeal and practical weather protection for garden buildings, house extensions, and feature walls.

Quality Assurance - We started DIY Building Supplies after growing frustrated with poor quality products and disappointing service in the industry. All our timber is carefully selected from responsible sources, with proper grading and treatment to ensure it performs as expected in your projects.

Expert Guidance - Our knowledgeable team brings years of practical experience to help you select the right timber for your specific requirements. Whether you're unsure about strength grades, treatment types, or calculating quantities, we're just a phone call or email away with expert advice.

Nationwide Delivery - We ship our complete timber range across mainland UK, ensuring your materials arrive safely and on schedule. Our efficient logistics network handles timber with care, protecting it during transit to prevent damage.

Competitive Pricing - By building direct relationships with suppliers and operating efficiently, we offer trade-quality timber at competitive prices. Our online model keeps overheads low, allowing us to pass savings directly to you without compromising on quality.

For stud walls, use 3x2 CLS (38x63mm) for non-load-bearing walls and 4x2 CLS (38x89mm) for load-bearing or external walls. For floor joists at 400mm centres, 4x2 (47x100mm) suits spans up to 1.8m, 6x2 (47x150mm) up to 2.7m, and 8x2 (47x200mm) up to 3.6m.

For roof rafters at 400mm centres, 4x2 (47x100mm) works for spans up to 1.9m, 5x2 (47x125mm) up to 2.3m, and 6x2 (47x150mm) up to 2.7m. These are general guidelines. For critical structures, always check building regulations or get professional advice.

The numbers C16 and C24 refer to the timber’s strength grade, showing its bending strength in newtons per square millimetre. C16 timber has a bending strength of 16 N/mm², while C24 is stronger at 24 N/mm².

C16 is suitable for most general building tasks like wall studs and floor joists in homes. C24 is used for heavier-duty jobs like longer floor joists, roof rafters, and load-bearing beams.

For typical domestic projects, C16 is strong enough and more cost-effective. But if structural requirements demand it or for longer spans and heavier loads, C24 is the better choice.

Pressure treated timber refers to a process used to treat wood in order to make it more resistant to decay, insects, and other environmental hazards. The process involves placing the wood in a pressure chamber and then forcing a preservative solution into the wood under high pressure. This allows the preservative chemicals to penetrate deep into the wood fibers, providing long-lasting protection. These chemicals help to inhibit the growth of fungi, insects, and other organisms that can cause decay or damage to the wood.

Much of our structural timber is available treated and in fact, treated timber is the more commonly used of the two. Typically, our timber is treated to UC2 - which has some resistance to pest and moisture and is best suited for wall, floor and ceiling construction. Some of our timbers for outdoor use (decking, fencing) are treated for higher moisture and pest resistance.

Kiln-dried timber is wood that has been carefully dried in a controlled environment, typically a large oven or kiln. This process removes excess moisture from the wood, reducing its moisture content to a specific level suitable for various applications. Kiln drying helps to minimize the wood's susceptibility to warping, shrinking, and cracking, while also improving its strength and stability. The controlled drying process ensures that the wood reaches a uniform moisture content throughout, making it more predictable and consistent in its performance. Kiln-dried timber is often preferred for construction, furniture making, and woodworking projects where stability, strength, and dimensional accuracy are important factors.

Regularised timber refers to timber that has been processed to achieve consistent dimensions and smooth surfaces. This processing typically involves trimming and planing the wood to standardized sizes and shapes, ensuring uniformity in thickness, width, and length. This often results in the timber being a few mm smaller in width and thickness than their "official" size, but is so minimal that it is likely to have no impact on the large majority of projects.

Store timber flat on a level surface with evenly spaced supports to avoid sagging. Keep it raised off the ground in a dry, covered area away from rain and direct sunlight.Cover it with a breathable material to protect from dust

Before using, allow air to circulate around the timber and acclimatise it to its final environment for 1–2 weeks. For long-term storage, check regularly for moisture or insect damage and rotate your stock if possible.

Treated timber typically lasts 15-30 years above ground, 10-20 years in ground contact, and 5-15 years in severe exposure conditions. Its lifespan depends on treatment level, timber type, and exposure. Proper maintenance can help extend its durability.