{"product_id":"pir-insulation-board-foil-faced-2400-x-1200mm","title":"PIR Insulation Board – Foil-Faced Rigid Board for Warm Roofs, 2400 x 1200mm, 6 Thicknesses","description":"\u003cp\u003eOn a warm roof the insulation sits above the deck and below the waterproofing, which means it does two jobs at once: it carries the thermal performance and it keeps the deck warm enough to stay out of the condensation risk zone.\u003c\/p\u003e\n\u003cp\u003eRigid PIR is the standard board for that build-up because it delivers a given U-value in the least thickness — useful when an extension roof has a fixed height to work to.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eFoil-faced rigid PIR board, 2400 x 1200mm (2.88m² per board)\u003c\/li\u003e\n\u003cli\u003eSix thicknesses from 25mm to 100mm — build up thickness to hit your target U-value\u003c\/li\u003e\n\u003cli\u003eThermal conductivity 0.022 W\/mK\u003c\/li\u003e\n\u003cli\u003eSold as individual boards, so you order exactly what the roof needs\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecification\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eBoard size\u003c\/th\u003e\n\u003ctd\u003e2400 x 1200mm (2.88m² per board)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eThicknesses\u003c\/th\u003e\n\u003ctd\u003e25mm, 30mm, 40mm, 50mm, 75mm, 100mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCore\u003c\/th\u003e\n\u003ctd\u003eRigid polyisocyanurate (PIR)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFacings\u003c\/th\u003e\n\u003ctd\u003eLow-emissivity composite foil, both faces\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eThermal conductivity\u003c\/th\u003e\n\u003ctd\u003e0.022 W\/mK\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eApplications\u003c\/th\u003e\n\u003ctd\u003eWarm flat roof, pitched roof, wall and floor construction\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eSupplied as\u003c\/th\u003e\n\u003ctd\u003eSingle boards\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch3\u003eFrequently asked questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eHow many boards do I need?\u003c\/strong\u003e Each board covers 2.88m². Divide your roof area by 2.88 and round up, allowing extra for cuts around upstands and outlets — most roofs waste 5–10% on cutting.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhich thickness should I choose?\u003c\/strong\u003e Thickness is driven by the U-value your project has to meet, so check your building control requirement or specification rather than guessing.\u003c\/p\u003e\n\u003cp\u003eWhere headroom or upstand height is tight, PIR's low conductivity means you reach a target with less depth than most alternatives.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan I stack two thinner boards instead of one thick one?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes — laying two layers with staggered joints is common practice and helps reduce thermal bridging through the joints, though it adds a little labour.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes it go above or below the deck?\u003c\/strong\u003e For a warm roof, above the deck and below the waterproofing layer, with a vapour control layer beneath the insulation.\u003c\/p\u003e\n\u003cp\u003eInsulating below the deck instead creates a cold roof, which is a different build-up with its own ventilation requirements.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat fire performance does it have?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eFire classification varies by manufacturer and board type, so we don't quote a rating here — check the datasheet for the board supplied, or ask us before ordering if your project has a specific fire requirement.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes my roof need a fall built in as well as insulation?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIf your deck doesn't already fall to the outlets, our \u003ca href=\"\/products\/tapered-pir-roof-insulation-board-flat-roof-drainage-fall-system-3-thickness-bands\"\u003eTapered PIR Roof Insulation Board\u003c\/a\u003e creates that drainage fall at insulation level instead of using this constant-thickness board.\u003c\/p\u003e\n\u003cp\u003eBuilding a warm flat roof?\u003c\/p\u003e\n\u003cp\u003eLay our \u003ca href=\"\/products\/polythene-vapour-control-layer-vcl-4m-x-25m\"\u003epolythene vapour control layer\u003c\/a\u003e beneath these boards, then finish with either our \u003ca href=\"\/products\/flexiproof-epdm-contact-bonding-adhesive\"\u003eEPDM contact bonding adhesive\u003c\/a\u003e-bonded rubber membrane or our \u003ca href=\"\/products\/pvc-single-ply-roofing-membrane\"\u003ePVC single-ply roofing membrane\u003c\/a\u003e as the top waterproofing layer, and finish the perimeter with our \u003ca href=\"\/products\/upvc-gutter-drip-trim-for-epdm-roofs-2-5m\"\u003euPVC gutter drip trim\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003eIf the roof above this insulation is a metal-clad finish rather than a membrane, our \u003ca href=\"\/products\/standing-seam-steel-roofing-sheet\"\u003estanding seam roofing sheet system\u003c\/a\u003e is a suitable concealed-fix covering for the same warm-roof build-up.\u003c\/p\u003e\n\u003cp\u003eIf your build-up needs to breathe rather than seal completely — timber-frame, period or listed reroofs — our \u003ca href=\"\/products\/wood-fibre-sarking-insulation-board-breathable-timber-frame\"\u003ewood fibre sarking \u0026amp; insulation board\u003c\/a\u003e is the vapour-open alternative to this foil-faced PIR.\u003c\/p\u003e","brand":"Rubber Roof UK","offers":[{"title":"25mm","offer_id":46002499092671,"sku":"RRUK-PIR-2412-25","price":50.99,"currency_code":"GBP","in_stock":true},{"title":"30mm","offer_id":46002499125439,"sku":"RRUK-PIR-2412-30","price":54.99,"currency_code":"GBP","in_stock":true},{"title":"40mm","offer_id":46002499158207,"sku":"RRUK-PIR-2412-40","price":62.99,"currency_code":"GBP","in_stock":true},{"title":"50mm","offer_id":46002499190975,"sku":"RRUK-PIR-2412-50","price":76.99,"currency_code":"GBP","in_stock":true},{"title":"75mm","offer_id":46002499223743,"sku":"RRUK-PIR-2412-75","price":98.99,"currency_code":"GBP","in_stock":true},{"title":"100mm","offer_id":46002499256511,"sku":"RRUK-PIR-2412-100","price":110.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0598\/1804\/9727\/files\/pir-insulation-boards-installed-warm-flat-roof.jpg?v=1786480505","url":"https:\/\/rubberroofuk.uk\/products\/pir-insulation-board-foil-faced-2400-x-1200mm","provider":"Rubber Roof UK","version":"1.0","type":"link"}