Frequently asked questions
| What strength classes are available for construction timber? | |
Structural timber is graded into different strength classes such as C16 and C24. These are our most common and are used for the majority of construction projects. | |
| When is C24 used compared to C16? | |
C24 is used for load-bearing structures such as beams and joists in floor systems. C16 is typically used for wall studs in load-bearing interior and exterior walls | |
| What is the difference between untreated and treated carcassing? | |
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. The majority of treated carcassing is UC2 for indoor use, whilst UC4 can be treated upon request for exterior use. | |
| How do I store timber correctly to prevent damage? | |
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| How do I choose the right size timber? | |
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, TR26 may be necessary. Contact customer service for assistance. | |
| Where can I buy Södra’s products? | |
For you as a private customer, our products are available through several builders’ merchants and retailers across the country. To find the right retailer, we recommend that you:
If you are a purchaser and would like to get in touch with us, please contact one of our sales representatives via Contact us. |
For contruction - Standard
C24
Södra is a leading supplier of high-quality, structural C24 carcassing timber – available in lengths from 2.4 to 7.2 m. Our C24 carcassing timber can withstand the most demanding requirements and outperforms C16 timber for many applications. Denser, more durable and less prone to twisting or bowing, it’s perfect for construction and joinery applications.
We carry extensive stocks of both untreated and treated carcassing across our terminal operations.
We have high-pressure and low-pressure preservative treatment facilities at both New Holland and Sheerness along with low-pressure facilities at Dundee and Wicklow enabling us to treat to your requirements upon request.
Features & Benefits
High-Performance Timber You Can Trust
C24 carcassing timber from Södra offers superior strength, stability, and durability for demanding structural and joinery applications. Denser and more resilient than C16, it’s kiln-dried, sustainably sourced, and available in a wide range of lengths – making it the smart choice for high-performance building projects.
Strength graded to BSEN 14081 – reliable structural performance
Kiln dried – lighter, stronger, and resistant to decay
PEFC certified – sustainably sourced with full chain-of-custody
Nationwide delivery – fast and easy access across the country
maximum durability
UC4 treated deck joists
UC4 treated deck joists are pressure-treated timber beams specifically designed to withstand ground contact and prolonged exposure to moisture. Classified under Use Class 4 (UC4), they are suitable for outdoor applications where the wood is in constant contact with wet conditions—such as the structural framework of decking.
The treatment extends the lifespan without compromising strength. They are typically made from kiln-dried C24 graded timber, treated for maximum durability.
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