TR 26

Structural timber is graded into different strength classes such as C14, C24, and C30. C24 is the most common and is used for the majority of construction projects. 

C24 is used for load-bearing structures such as beams and joists in floor systems. 
It is stronger and more durable, making it suitable for constructions that need to withstand higher loads. 

C14 is typically used for wall studs in load-bearing interior and exterior walls 
where the requirements for deformation are not as high. 

Untreated carcassing is natural and used indoors or in protected environments. Treated carcassing is treated to resist moisture and rot, making it suitable for outdoor use. 

• Protect from Moisture: Store the timber in a dry place, protected from rain and ground moisture. Use pallets or similar supports to keep the wood off the ground. 

• Ventilation: Ensure that air can circulate around the timber. This helps prevent mould and rot. 

• Protect from Sunlight: Avoid direct sunlight, as it can cause cracking and warping. 

• Covering: Use a tarpaulin or other protective covering, but make sure there is space for the air to circulate. 

• Regular Inspection: Check the wood regularly to ensure it hasn’t been damaged or exposed to moisture. 

The size you need depends on what you’re building. Common dimensions are 45 x 95 mm and 45 x 145 mm. For load-bearing structures such as roof trusses, C30 may be necessary. Contact customer service for assistance.

Södra’s products are available at many building supply stores and retailers. To find the right stockist, we recommend that you: 

• Visit your local building supplier – they often carry our products in stock or can order them for you. 

• Contact our customer service – they’ll be happy to help find a store near you.