{"product_id":"polythene-vapour-control-layer-vcl-4m-x-25m","title":"Polythene Vapour Control Layer – Virgin Grade VCL for Warm Roofs, 4m x 25m","description":"\u003cp\u003eEvery warm roof needs a vapour control layer under the insulation, and it isn't optional detailing — it's the layer that stops warm, moist air from inside the building reaching the cold side of the build-up and condensing there.\u003c\/p\u003e\n\u003cp\u003eSkip it or lap it badly and the problem shows up years later as a saturated deck.\u003c\/p\u003e\n\u003cp\u003eThis is virgin-grade polythene VCL in a translucent green tint, so you can see your fixing lines through it as you lay.\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eVirgin-grade polythene vapour control layer, 4m x 25m roll covering 100m²\u003c\/li\u003e\n\u003cli\u003eTwo gauges: 1000 gauge (250 micron) and heavier-duty 1200 gauge (300 micron)\u003c\/li\u003e\n\u003cli\u003eTranslucent green tint — see through to the deck for accurate fixing\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eSpecification\u003c\/h2\u003e\n\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eRoll size\u003c\/th\u003e\n\u003ctd\u003e4m x 25m (100m² per roll)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eGauges\u003c\/th\u003e\n\u003ctd\u003e1000 gauge (250 micron), 1200 gauge (300 micron)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eVirgin-grade blown polythene\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eColour\u003c\/th\u003e\n\u003ctd\u003eTranslucent green tint\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003ePosition in build-up\u003c\/th\u003e\n\u003ctd\u003eAbove the deck, beneath the insulation (warm roof)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003ch3\u003eFrequently asked questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhich gauge should I choose?\u003c\/strong\u003e 1000 gauge is the usual specification for domestic warm roofs.\u003c\/p\u003e\n\u003cp\u003eStep up to 1200 gauge where the membrane will see more foot traffic during the build, or where the specification calls for a heavier-duty layer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhere exactly does it go?\u003c\/strong\u003e Directly on the deck, beneath the insulation.\u003c\/p\u003e\n\u003cp\u003eThe order is deck, then VCL, then insulation, then waterproofing — that keeps the vapour barrier on the warm side of the insulation, which is the whole point of it.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much do I need?\u003c\/strong\u003e Each roll covers 100m². Allow generous laps at every joint and turn the membrane up at perimeters and upstands, so order comfortably more than the bare roof area.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow are the joints sealed?\u003c\/strong\u003e Lap the sheets and seal the laps with a suitable vapour barrier tape. A VCL only performs if it's continuous, so laps, penetrations and perimeter upstands all need sealing.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs a VCL the same as a breather membrane?\u003c\/strong\u003e No, and they aren't interchangeable. A VCL resists vapour and goes under the insulation on a warm roof.\u003c\/p\u003e\n\u003cp\u003eA breather membrane is designed to let vapour out and belongs in a ventilated pitched roof build-up.\u003c\/p\u003e\n\u003cp\u003eBuilding a warm flat roof? This sits directly beneath our \u003ca href=\"\/products\/pir-insulation-board-foil-faced-2400-x-1200mm\"\u003efoil-faced PIR insulation board\u003c\/a\u003e, with \u003ca href=\"\/products\/1-2mm-epdm-rubber-roofing-membrane\"\u003e1.2mm EPDM membrane\u003c\/a\u003e bonded over the top using our \u003ca href=\"\/products\/flexiproof-epdm-contact-bonding-adhesive\"\u003eEPDM contact bonding adhesive\u003c\/a\u003e.\u003c\/p\u003e\n\u003cp\u003eIf the specification calls for a hot-air-welded, contractor-installed finish instead, our \u003ca href=\"\/products\/pvc-single-ply-roofing-membrane\"\u003ePVC single-ply roofing membrane\u003c\/a\u003e is a suitable alternative top layer over the same VCL and insulation build-up.\u003c\/p\u003e","brand":"Rubber Roof UK","offers":[{"title":"1000 gauge (250 micron)","offer_id":46002508497087,"sku":"RRUK-VCL-POLY-1000G-4X25","price":319.99,"currency_code":"GBP","in_stock":true},{"title":"1200 gauge (300 micron)","offer_id":46002508529855,"sku":"RRUK-VCL-POLY-1200G-4X25","price":362.99,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0598\/1804\/9727\/files\/polythene-vapour-control-layer-flat-roof-deck.jpg?v=1786480505","url":"https:\/\/rubberroofuk.uk\/products\/polythene-vapour-control-layer-vcl-4m-x-25m","provider":"Rubber Roof UK","version":"1.0","type":"link"}