{"product_id":"wood-fibre-sarking-insulation-board-breathable-timber-frame","title":"Wood Fibre Sarking \u0026amp; Insulation Board – Breathable Timber-Frame Roof Board, 3 Thicknesses","description":"\u003cp\u003eFoam insulation boards do one job well: they stop heat escaping. What they don't do is let a roof breathe — trap the wrong kind of moisture behind a foil-faced PIR board on a timber-frame or period building and it has nowhere to go. Wood fibre board is the answer roofers reach for on breathable build-ups: a rigid board pressed from compressed softwood fibre, vapour-open enough to let a roof structure dry out in both directions while still doing genuine insulating and wind-bracing work.\u003c\/p\u003e\n\n\u003cp\u003eWe stock it in two distinct roles. The 22mm board is a racking and sarking board — fixed straight across rafters as a breathable alternative to OSB or plywood sarking, giving the roof structure rigidity and wind resistance before the counter-battens and covering go on. The 80mm and 100mm boards are the insulation-grade version of the same material, used where a genuinely vapour-permeable insulation layer matters more than squeezing the last millimetre of thickness out of a warm roof build-up — timber-frame extensions, listed and period reroofs, and anywhere the design calls for a breathing roof rather than a sealed one.\u003c\/p\u003e\n\n\u003ch3\u003eKey benefits\u003c\/h3\u003e\n\u003cp\u003eVapour-permeable — lets moisture pass through and disperse rather than trapping it against timber. Hygroscopic — the fibre structure buffers and releases moisture vapour, which helps manage condensation risk in breathable constructions. Tongue-and-groove long edges on every board for a tight, draught-resistant joint without extra tape. Genuine wind-bracing value on the 22mm sarking board when fixed correctly across rafters. Natural, largely bio-based material for anyone specifying toward a lower-impact build-up.\u003c\/p\u003e\n\n\u003ch3\u003eSuitable applications\u003c\/h3\u003e\n\u003cp\u003ePitched roof sarking\/racking under tiles, slates or shingles on timber-frame construction. Warm roof and rafter-level insulation on breathable build-ups where PIR isn't the right fit. Period and listed-building reroofs where the original structure needs to keep breathing. Companion insulation layer alongside our \u003ca href=\"https:\/\/rubberroofuk.uk\/products\/breathable-roofing-membrane-125gsm-roof-wall-underlay\"\u003ebreathable roofing membrane\u003c\/a\u003e, which is the vapour-permeable underlay this board is designed to work with.\u003c\/p\u003e\n\n\u003ch3\u003eSpecification\u003c\/h3\u003e\n\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eVariant\u003c\/th\u003e\n\u003cth\u003eBoard size\u003c\/th\u003e\n\u003cth\u003eCoverage per board\u003c\/th\u003e\n\u003cth\u003eRole\u003c\/th\u003e\n\u003cth\u003eEdge detail\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e22mm Sarking Board\u003c\/td\u003e\n\u003ctd\u003e2230 x 600mm\u003c\/td\u003e\n\u003ctd\u003e≈1.34m²\u003c\/td\u003e\n\u003ctd\u003eRacking\/sarking board (wind bracing, breathable roof deck)\u003c\/td\u003e\n\u003ctd\u003eTongue \u0026amp; groove\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e80mm Insulation Board\u003c\/td\u003e\n\u003ctd\u003e2230 x 600mm\u003c\/td\u003e\n\u003ctd\u003e≈1.34m²\u003c\/td\u003e\n\u003ctd\u003eRafter-level insulation, breathable build-up\u003c\/td\u003e\n\u003ctd\u003eTongue \u0026amp; groove\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e100mm Insulation Board\u003c\/td\u003e\n\u003ctd\u003e2230 x 600mm\u003c\/td\u003e\n\u003ctd\u003e≈1.34m²\u003c\/td\u003e\n\u003ctd\u003eHigher-thickness rafter-level insulation\u003c\/td\u003e\n\u003ctd\u003eTongue \u0026amp; groove\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eInstallation \u0026amp; ordering guidance\u003c\/h3\u003e\n\u003cp\u003eFix across rafters with the tongue-and-groove edges engaged, following your roofing contractor's or the manufacturer's datasheet for fixing centres and counter-batten detail — this varies with rafter spacing and roof pitch, so we don't state a single fixing pattern here. Keep boards dry and off wet ground until they're covered; like any wood-based board, prolonged exposure to standing water before installation isn't good for it. Pair the 22mm sarking board with our \u003ca href=\"https:\/\/rubberroofuk.uk\/products\/breathable-roofing-membrane-125gsm-roof-wall-underlay\"\u003ebreathable roofing membrane\u003c\/a\u003e over the top, and see our \u003ca href=\"https:\/\/rubberroofuk.uk\/products\/pir-insulation-board-foil-faced-2400-x-1200mm\"\u003ePIR insulation board\u003c\/a\u003e if your build-up calls for a sealed, foil-faced warm-roof board instead of a breathable one — they solve different problems and it's worth checking which one your design actually needs before ordering.\u003c\/p\u003e\n\n\u003ch3\u003eFAQs\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhat's actually different between the 22mm board and the 80\/100mm boards?\u003c\/strong\u003e The 22mm is a thin racking\/sarking board — its job is structural bracing and breathability under the roof covering, not meaningful insulation value. The 80mm and 100mm boards are the insulation-grade version of the same wood fibre material, thick enough to contribute real thermal performance in a breathable build-up.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eShould I use this instead of your PIR insulation board?\u003c\/strong\u003e Not automatically. PIR is the simpler, higher-performance-per-millimetre choice for a standard sealed warm roof. Wood fibre earns its place specifically where the design needs to breathe — timber-frame, period or listed work, or anywhere a vapour-open build-up is specified. If you're not sure which your roof needs, that's worth checking with whoever specified the build-up before you order.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it need to be protected once fixed?\u003c\/strong\u003e Yes — like any wood-fibre or timber board, it should be covered by the roofing membrane and covering within a reasonable window and not left exposed to prolonged wet weather.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat fixings should I use?\u003c\/strong\u003e Standard roofing screws or nails sized for the board thickness and your batten\/counter-batten detail; we don't sell a proprietary fixing kit for this board, so use fixings rated for the load and spacing your roof design specifies.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow quickly does this dispatch?\u003c\/strong\u003e The 22mm and 80mm boards are quick-turnaround stock items. The 100mm board is a lower-volume line with a longer lead time — please allow around 4–5 weeks for that thickness specifically, and order early if it's on your critical path.\u003c\/p\u003e\n\n\u003cp\u003e\u003cem\u003eCustom, unbranded product — see our \u003ca href=\"https:\/\/rubberroofuk.uk\/products\/breathable-roofing-membrane-125gsm-roof-wall-underlay\"\u003ebreathable roofing membrane\u003c\/a\u003e and \u003ca href=\"https:\/\/rubberroofuk.uk\/products\/pir-insulation-board-foil-faced-2400-x-1200mm\"\u003ePIR insulation board\u003c\/a\u003e for the companion products most often ordered alongside this one.\u003c\/em\u003e\u003c\/p\u003e","brand":"Rubber Roof UK","offers":[{"title":"22mm Sarking Board","offer_id":46139697070271,"sku":"RRUK-WFB-22MM","price":29.99,"currency_code":"GBP","in_stock":true},{"title":"80mm Insulation Board","offer_id":46139697103039,"sku":"RRUK-WFB-80MM","price":84.99,"currency_code":"GBP","in_stock":true},{"title":"100mm Insulation Board","offer_id":46139697135807,"sku":"RRUK-WFB-100MM","price":109.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0598\/1804\/9727\/files\/wood-fibre-sarking-board-installed-roof-rafters-58fcc980-a114-41e2-915a-081316f20a44.jpg?v=1788509365","url":"https:\/\/rubberroofuk.uk\/products\/wood-fibre-sarking-insulation-board-breathable-timber-frame","provider":"Rubber Roof UK","version":"1.0","type":"link"}