{"product_id":"treated-timber-joist-47-x-150mm-c24","title":"Treated Timber Joist 47 x 150mm C24","description":"\u003ch3\u003eTreated Timber Joist 47 x 150mm C24\u003c\/h3\u003e\n\nTreated 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.\n\nEach 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.\n\nThe 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.\n\nResponsibly sourced and PEFC 70% certified, these joists combine performance, sustainability, and precision, making them a trusted choice for professional builders and DIY enthusiasts alike.\n\n\u003ch3\u003eKey Specifications\u003c\/h3\u003e \u003cul\u003e \u003cli\u003e\n\u003cstrong\u003eSection Size:\u003c\/strong\u003e 47 x 150mm\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eFinished Size (Approx.):\u003c\/strong\u003e 45 x 145mm\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eLengths Available:\u003c\/strong\u003e 3.0m, 3.6m, 4.2m, 4.8m, 6.0m\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eGrade:\u003c\/strong\u003e C24 (Structural)\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eTreatment:\u003c\/strong\u003e Pressure Treated for protection and durability\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eFinish:\u003c\/strong\u003e Planed and Regularised with Eased Edges\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eMoisture Content:\u003c\/strong\u003e Kiln Dried for improved stability\u003c\/li\u003e \u003cli\u003e\n\u003cstrong\u003eCertification:\u003c\/strong\u003e 70% PEFC Certified\u003c\/li\u003e \u003c\/ul\u003e \u003ch3\u003eFAQs\u003c\/h3\u003e \u003ch4\u003eWhat does C24 mean for treated timber joists?\u003c\/h4\u003e 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. \u003ch4\u003eCan C24 treated timber be used externally?\u003c\/h4\u003e 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. \u003ch4\u003eWhy is kiln drying beneficial for treated timber?\u003c\/h4\u003e 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.\u003cbr\u003e\u003cp\u003eCheck out our full range of \u003ca href=\"https:\/\/jjbuildingmaterials.co.uk\/collections\/timber\"\u003etimber\u003c\/a\u003e.\u003c\/p\u003e\u003cp\u003eBrowse more \u003ca href=\"https:\/\/jjbuildingmaterials.co.uk\/collections\/timber-lengths\"\u003etimber lengths\u003c\/a\u003e available online.\u003c\/p\u003e","brand":"JJ Building Materials","offers":[{"title":"3.0m","offer_id":51585205436758,"sku":"T00001156","price":10.29,"currency_code":"GBP","in_stock":true},{"title":"3.6m","offer_id":51585205469526,"sku":"T00001157","price":12.34,"currency_code":"GBP","in_stock":true},{"title":"4.2m","offer_id":51585205502294,"sku":"T00001158","price":14.41,"currency_code":"GBP","in_stock":true},{"title":"4.8m","offer_id":51585205535062,"sku":"T00001159","price":19.71,"currency_code":"GBP","in_stock":true},{"title":"6.0m","offer_id":51585205567830,"sku":"T00001161","price":32.8,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0905\/4509\/4998\/files\/treated-timber-joist-47-x-150mm-c24-1763559.jpg?v=1772656456","url":"https:\/\/jjbuildingmaterials.co.uk\/products\/treated-timber-joist-47-x-150mm-c24","provider":"JJ Building Materials","version":"1.0","type":"link"}