Treated Timber Joist 47 x 150mm C24
Treated Timber Joists are a dependable and high-quality choice for a wide range of structural construction projects. Often referred to as softwood carcassing timber, these joists are strength-graded to C24, providing exceptional structural performance and reliability for use in load-bearing applications.
Each joist is pressure treated to improve durability and protect against fungal decay, rot, and insect attack, making it suitable for above-ground use where there’s an occasional risk of moisture. The timber is planed and regularised, ensuring smooth surfaces, uniform dimensions, and eased edges for easy handling and a clean, professional appearance once installed.
The boards are also kiln-dried, reducing moisture content to a stable level that enhances both strength and dimensional stability while minimising the risk of twisting or warping. Available in multiple lengths — from 3.0m to 6.0m — these joists are ideal for constructing floors, roofs, walls, decking frames, and general carcassing.
Responsibly sourced and PEFC 70% certified, these joists combine performance, sustainability, and precision, making them a trusted choice for professional builders and DIY enthusiasts alike.
Key Specifications
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Section Size: 47 x 150mm
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Finished Size (Approx.): 45 x 145mm
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Lengths Available: 3.0m, 3.6m, 4.2m, 4.8m, 6.0m
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Grade: C24 (Structural)
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Treatment: Pressure Treated for protection and durability
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Finish: Planed and Regularised with Eased Edges
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Moisture Content: Kiln Dried for improved stability
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Certification: 70% PEFC Certified
FAQs
What does C24 mean for treated timber joists?
C24 is a high-grade structural classification that ensures superior strength, stability, and performance. It’s ideal for load-bearing applications such as flooring, roofing, decking, and wall framing.
Can C24 treated timber be used externally?
Yes, it can be used in exterior applications where there’s occasional exposure to moisture, such as decking frameworks or outdoor structural work. However, for ground contact or constantly damp conditions, use timber treated to a higher specification.
Why is kiln drying beneficial for treated timber?
Kiln drying removes excess moisture from the timber, helping to reduce the risk of twisting, splitting, or warping. It also enhances the effectiveness of preservative treatments and ensures long-term strength and stability.
Check out our full range of timber.
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