47mm x 175mm Sawn Treated Timber C24 (7" x 2") 3.6m

What Is 7x2 3.6m Timber?

47mm x 175mm Sawn Treated Timber C24 (7" x 2") 3.6m is a robust structural softwood section graded to C24, ideal for use in load-bearing construction. Supplied in a 3.6m length, it is commonly used for floor joists, roof rafters, wall plates, and general structural framing in both residential and commercial construction, where higher strength and reduced deflection - the degree to which a structural member bends or sags under load - are required to maintain stability and minimise movement.

The timber is planed all round (PAR) with eased edges, resulting in a smooth surface for easier handling and a clean, uniform finish. Although nominally sized at 47mm x 175mm, the finished dimensions are approximately 45mm x 170mm.

Manufactured from slow-grown softwood such as spruce or pine, our 7x2 3.6m is kiln-dried for stability, pressure treated to resist fungal decay and insect attack, and strength-graded to C24 under BS EN 338. Its enhanced mechanical properties allow for longer spans and greater load capacities than lower-grade alternatives such as C16.

Longer lengths and other timber sizes are also available online and by enquiry.

Please Note: The finished size of our carcassing timber may vary slightly from the nominal dimensions. You can expect to receive timber that is finished with a thickness 2mm less and a width 5mm less than the nominal measurements stated. Colour and finish are representative only and may vary slightly as this is a natural product.

Applications 

• Floor joists in domestic or light commercial builds 
• Roof rafters for pitched roof construction
• Ceiling joists in habitable spaces
• Wall plates for fixing roof structures to masonry walls
• Decking joists and subframes for heavy-duty timber decking
• Beams or supports in pergolas and garden structures
• Structural framing for garages, carports, and outbuildings
• Trimmers (used to frame and support openings in floors or roofs, such as staircases or loft hatches)
• Noggins (installed horizontally between joists or studs to prevent twisting and provide additional fixing points for boards or cladding)

Benefits

• C24 strength graded: Offers superior strength, stiffness, and load-bearing capacity compared to C16, allowing longer spans and reduced deflection.
• Pressure treated for durability: Treated with preservative to protect against fungal decay and insect attack, extending lifespan in external or moisture-prone environments.
• Suitable for structural applications: Compliant with building regulations for use in load-bearing roles such as floor joists, roof rafters, and wall plates.
• Planed all round (PAR) with eased edges: Smooth finish improves handling safety and provides a clean, professional appearance.
• Good workability: Can be cut, drilled, and fixed using standard woodworking tools; compatible with nails, screws, bolts, and structural fixings.
• Improved fixing strength: Higher density and quality of C24 grade timber offers better holding power for fixings compared to lower grades.
• Fewer defects: Contains fewer knots and strength-reducing imperfections than lower-grade timber, improving structural reliability and aesthetics.

Understanding C24 Timber

C24 timber is a structural strength grade defined by BS EN 338, offering higher strength and stiffness than standard C16 timber. It is kiln-dried, strength-graded (visually or by machine), and meets strict standards for load-bearing applications.

Compared to C16, C24 timber has fewer and smaller knots, higher bending and compression strength, and a greater resistance to deflection under load. This makes it ideal for structural uses such as floor joists, roof rafters, and other applications where performance, safety, and compliance with building regulations are essential.

Timber Sizing Explained

Here at Materials Market, all of the timber we sell is treated with preservatives, kiln dried, and then planed on all four sides to give it an easi edge profile that makes for easy handling. Our 7x2 timber offers longer lengths of up to 6m.

Timber sizes are often referred to as either nominal or finished. With a nominal size of 47mmx175mm, this product actually has a finished size of 45mmx170mm, but this difference is so negligible that it is commonly just referred to as 47x175, or 7x2.