{"product_id":"torch-on-perforated-roofing-underlay-20m-x-1m-roll","title":"Torch-On Perforated Roofing Underlay – 20m x 1m Roll","description":"\u003cp\u003eTorch-On Perforated Underlay is an economical, glass-fibre reinforced bitumen membrane designed to form a preparation and ventilation layer beneath compatible torch-on roofing systems. Suitable for both new-build and refurbishment projects, it helps create a controlled, partially bonded waterproofing system across a range of suitable substrates.\u003c\/p\u003e\n\u003cp\u003eThe membrane is loose-laid before the next torch-applied underlay is installed. Evenly distributed 40mm perforations allow the overlying underlay to bond through to the substrate, creating a consistent pattern of adhesion.\u003c\/p\u003e\n\u003cp\u003eThis partial bond allows water vapour to move beneath the waterproofing system towards suitably positioned roof vents, where it can escape.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eKey Features\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e20m x 1m roll: 20m² gross roll area before overlaps and cutting.\u003c\/li\u003e\n\u003cli\u003ePerforated construction: Evenly spaced 40mm holes provide controlled bonding points.\u003c\/li\u003e\n\u003cli\u003eGlass-fibre reinforcement: Perforated glass-fibre mat within a polymer-modified bitumen compound.\u003c\/li\u003e\n\u003cli\u003eVentilation layer: Allows water vapour to move beneath the waterproofing system towards suitable roof vents.\u003c\/li\u003e\n\u003cli\u003eLoose-laid installation: Secured during application of the subsequent torch-applied underlay.\u003c\/li\u003e\n\u003cli\u003eBurn-off film: Polyethylene film protects both sides of the membrane.\u003c\/li\u003e\n\u003cli\u003eVersatile use: Suitable for compatible new-build and refurbishment roofing systems.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eApplication\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eUse as the preparation and ventilation layer within a compatible, partially bonded torch-on roofing system. Lay the perforated membrane loose over the prepared substrate, then install the specified torch-applied underlay above it.\u003c\/p\u003e\n\u003cp\u003eThis product is a system preparation layer, not a standalone waterproof covering or exposed roof finish. Install in accordance with the roofing system manufacturer’s instructions, with suitable roof ventilation provisions. Torch-on application should be carried out by trained roofing professionals using appropriate fire precautions.\u003c\/p\u003e","brand":"Flat Roofing Systems","offers":[{"title":"Default Title","offer_id":57684322451782,"sku":"PERF\/20M","price":46.96,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0787\/0572\/1670\/files\/Torch_On_Perforated_20m.png?v=1792751969","url":"https:\/\/flatroofingsystems.co.uk\/products\/torch-on-perforated-roofing-underlay-20m-x-1m-roll","provider":"Flat Roofing Systems","version":"1.0","type":"link"}