{"product_id":"grp-internal-drain-outlet","title":"GRP Internal Drain Outlet – 50mm, 75mm, 82mm \u0026 100mm","description":"\u003ch3\u003eVertical Roof Outlet for Fibreglass GRP Roofing Systems\u003c\/h3\u003e\n\n\u003cp\u003eThis \u003cstrong\u003eGRP Internal Drain Outlet\u003c\/strong\u003e provides a secure vertical connection between a fibreglass roof and the rainwater downpipe below.\u003c\/p\u003e\n\n\u003cp\u003eDesigned specifically for GRP roofing systems, the outlet features a durable rigid pipe body with an integrated mesh flange, allowing the laminate to bond directly into the drainage detail for a seamless watertight finish.\u003c\/p\u003e\n\n\u003cp\u003eAvailable in \u003cstrong\u003e50mm, 75mm, 82mm and 100mm options\u003c\/strong\u003e to suit standard downpipe sizes.\u003c\/p\u003e\n\n\u003cdetails style=\"margin-bottom:12px; border:1px solid #333; border-radius:10px; background:#1a1a1a; overflow:hidden;\"\u003e\n  \u003csummary style=\"cursor:pointer; font-weight:700; padding:16px 48px 16px 16px; font-size:18px; position:relative;\"\u003e\n    Important – Choosing the Correct Size\n    \u003cspan style=\"position:absolute; right:16px; top:50%; transform:translateY(-50%);\"\u003e▸\u003c\/span\u003e\n  \u003c\/summary\u003e\n  \u003cdiv style=\"padding:16px; border-top:1px solid #333;\"\u003e\n    \u003cp\u003eThe size selected refers to the \u003cstrong\u003edownpipe size the outlet will fit into\u003c\/strong\u003e, not the diameter of the outlet itself.\u003c\/p\u003e\n    \u003cp\u003eThe outlet spigot is slightly smaller than the named size to ensure a snug and secure fit inside the corresponding pipe.\u003c\/p\u003e\n    \u003cp\u003eExample:\u003cbr\u003e\n    Selecting 50mm means the outlet is designed to fit into a 50mm downpipe.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/details\u003e\n\n\u003cdetails style=\"margin-bottom:12px; border:1px solid #333; border-radius:10px; background:#1a1a1a; overflow:hidden;\"\u003e\n  \u003csummary style=\"cursor:pointer; font-weight:700; padding:16px 48px 16px 16px; font-size:18px; position:relative;\"\u003e\n    What It’s Used For\n    \u003cspan style=\"position:absolute; right:16px; top:50%; transform:translateY(-50%);\"\u003e▸\u003c\/span\u003e\n  \u003c\/summary\u003e\n  \u003cdiv style=\"padding:16px; border-top:1px solid #333;\"\u003e\n    \u003cul\u003e\n      \u003cli\u003eForming internal vertical drainage points in GRP roofs\u003c\/li\u003e\n      \u003cli\u003eConnecting roof deck to rainwater downpipe\u003c\/li\u003e\n      \u003cli\u003eGRP outlet details in box gutters\u003c\/li\u003e\n      \u003cli\u003eReplacing or installing new internal outlets\u003c\/li\u003e\n      \u003cli\u003eDetailing balcony and flat roof drainage\u003c\/li\u003e\n    \u003c\/ul\u003e\n    \u003cp\u003eSuitable for use in traditional \u003ca href=\"\/collections\/grp-roof-1010\"\u003e\u003cstrong\u003eGRP fibreglass\u003c\/strong\u003e\u003c\/a\u003e \u0026amp; \u003cstrong\u003e\u003ca href=\"\/collections\/flexitec\"\u003eFlexitec roofing systems\u003c\/a\u003e\u003c\/strong\u003e.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/details\u003e\n\n\u003cdetails style=\"margin-bottom:12px; border:1px solid #333; border-radius:10px; background:#1a1a1a; overflow:hidden;\"\u003e\n  \u003csummary style=\"cursor:pointer; font-weight:700; padding:16px 48px 16px 16px; font-size:18px; position:relative;\"\u003e\n    Why Proper Drain Detailing Matters\n    \u003cspan style=\"position:absolute; right:16px; top:50%; transform:translateY(-50%);\"\u003e▸\u003c\/span\u003e\n  \u003c\/summary\u003e\n  \u003cdiv style=\"padding:16px; border-top:1px solid #333;\"\u003e\n    \u003cp\u003eDrain outlets are one of the most critical points on any flat roof.\u003c\/p\u003e\n    \u003cp\u003ePoor detailing can lead to:\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003eWater tracking beneath the laminate\u003c\/li\u003e\n      \u003cli\u003eLeaks at pipe connections\u003c\/li\u003e\n      \u003cli\u003eMovement failure around the outlet\u003c\/li\u003e\n    \u003c\/ul\u003e\n    \u003cp\u003eThe integrated mesh flange allows the base resin and CSM to fully encapsulate the flange, creating a secure mechanical bond within the GRP system.\u003c\/p\u003e\n    \u003cp\u003eOnce laminated and top coated, the outlet becomes fully integrated into the waterproof membrane.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/details\u003e\n\n\u003cdetails style=\"margin-bottom:12px; border:1px solid #333; border-radius:10px; background:#1a1a1a; overflow:hidden;\"\u003e\n  \u003csummary style=\"cursor:pointer; font-weight:700; padding:16px 48px 16px 16px; font-size:18px; position:relative;\"\u003e\n    Installation Overview (GRP System)\n    \u003cspan style=\"position:absolute; right:16px; top:50%; transform:translateY(-50%);\"\u003e▸\u003c\/span\u003e\n  \u003c\/summary\u003e\n  \u003cdiv style=\"padding:16px; border-top:1px solid #333;\"\u003e\n    \u003col\u003e\n      \u003cli\u003eCut the deck opening to suit the outlet body.\u003c\/li\u003e\n      \u003cli\u003eInsert the outlet through the deck.\u003c\/li\u003e\n      \u003cli\u003eMechanically secure if required.\u003c\/li\u003e\n      \u003cli\u003eLaminate over the mesh flange using base resin and CSM reinforcement.\u003c\/li\u003e\n      \u003cli\u003eConsolidate fully to remove air pockets.\u003c\/li\u003e\n      \u003cli\u003eApply top coat as part of the system finish.\u003c\/li\u003e\n    \u003c\/ol\u003e\n    \u003cp\u003eEnsure correct falls are formed to direct water towards the outlet.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/details\u003e\n\n\u003cdetails style=\"margin-bottom:12px; border:1px solid #333; border-radius:10px; background:#1a1a1a; overflow:hidden;\"\u003e\n  \u003csummary style=\"cursor:pointer; font-weight:700; padding:16px 48px 16px 16px; font-size:18px; position:relative;\"\u003e\n    Technical Specification\n    \u003cspan style=\"position:absolute; right:16px; top:50%; transform:translateY(-50%);\"\u003e▸\u003c\/span\u003e\n  \u003c\/summary\u003e\n  \u003cdiv style=\"padding:16px; border-top:1px solid #333;\"\u003e\n    \u003cul\u003e\n      \u003cli\u003eAvailable Sizes: 50mm \/ 75mm \/ 82mm \/ 100mm\u003c\/li\u003e\n      \u003cli\u003eOutlet Length: Approx. 200mm\u003c\/li\u003e\n      \u003cli\u003eMaterial: Rigid GRP-compatible body with mesh flange\u003c\/li\u003e\n      \u003cli\u003eApplication: Internal vertical drainage\u003c\/li\u003e\n    \u003c\/ul\u003e\n  \u003c\/div\u003e\n\u003c\/details\u003e\n\n\u003cdetails style=\"margin-bottom:12px; border:1px solid #333; border-radius:10px; background:#1a1a1a; overflow:hidden;\"\u003e\n  \u003csummary style=\"cursor:pointer; font-weight:700; padding:16px 48px 16px 16px; font-size:18px; position:relative;\"\u003e\n    Roofer’s Perspective\n    \u003cspan style=\"position:absolute; right:16px; top:50%; transform:translateY(-50%);\"\u003e▸\u003c\/span\u003e\n  \u003c\/summary\u003e\n  \u003cdiv style=\"padding:16px; border-top:1px solid #333;\"\u003e\n    \u003cp\u003eDrain details need to be right first time. A proper GRP outlet with a mesh flange laminates in cleanly and avoids awkward detailing around pipe penetrations.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/details\u003e","brand":"The Flat Roofing Shop","offers":[{"title":"50mm","offer_id":56660988297547,"sku":"GRP-DRAIN-050","price":30.6,"currency_code":"GBP","in_stock":true},{"title":"75mm","offer_id":56660988330315,"sku":"GRP-DRAIN-075","price":30.8,"currency_code":"GBP","in_stock":true},{"title":"82mm","offer_id":56660988363083,"sku":"GRP-DRAIN-082","price":32.4,"currency_code":"GBP","in_stock":true},{"title":"100mm","offer_id":56660988395851,"sku":null,"price":32.4,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0997\/4054\/9451\/files\/grp-internal-drain-x4-2.jpg?v=1774111453","url":"https:\/\/theflatroofingshop.co.uk\/products\/grp-internal-drain-outlet","provider":"The Flat Roofing Shop","version":"1.0","type":"link"}