{"product_id":"classicbond-epdm-water-cut-off-mastic","title":"ClassicBond EPDM Water Cut-Off Mastic","description":"\u003ch3\u003eCompression Sealant for EPDM Termination Bars \u0026amp; Fixings\u003c\/h3\u003e\n\n\u003cp\u003eClassicBond Water Cut-Off Mastic is a \u003cstrong\u003eone-component, extremely tacky butyl-blend sealant\u003c\/strong\u003e designed to create a watertight compression seal in EPDM rubber roofing systems.\u003c\/p\u003e\n\n\u003cp\u003eIt is applied beneath the membrane before mechanical termination, where it seals around fixings under compression - preventing water tracking into screw penetrations or behind termination bars.\u003c\/p\u003e\n\n\u003cp\u003eWhen compressed, the mastic “oozes” into gaps, forming a durable seal that remains flexible long-term.\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; list-style:none;\"\u003e\n    What Water Cut-Off Mastic Is 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    \u003cp\u003eWater Cut-Off Mastic is primarily used:\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003eBeneath \u003ca href=\"\/products\/termination-bar-for-epdm-rubber-roofing\"\u003e\u003cstrong\u003etermination bars\u003c\/strong\u003e\u003c\/a\u003e\n\u003c\/li\u003e\n      \u003cli\u003eBeneath balustrade fixings on balconies\u003c\/li\u003e\n      \u003cli\u003eAt compression-type wall terminations\u003c\/li\u003e\n      \u003cli\u003eAnywhere the membrane is mechanically fixed and compressed\u003c\/li\u003e\n    \u003c\/ul\u003e\n    \u003cp\u003eIt is not a surface sealant - it is a \u003cstrong\u003ecompression-type sealing agent\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; list-style:none;\"\u003e\n    Why It’s Critical for Termination Bars\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\u003eWhen a termination bar is fixed through the membrane:\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003eScrews penetrate the EPDM\u003c\/li\u003e\n      \u003cli\u003eWater can track along the fixings\u003c\/li\u003e\n      \u003cli\u003eMovement over time can create small voids\u003c\/li\u003e\n    \u003c\/ul\u003e\n    \u003cp\u003eWater Cut-Off Mastic is applied as an 11mm bead beneath the membrane, and when the termination bar is tightened down, it compresses and seals around every fixing point.\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; list-style:none;\"\u003e\n    Recommended System Practice\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\u003eIt is strongly recommended to use \u003cstrong\u003eWater Cut-Off Mastic beneath compression terminations\u003c\/strong\u003e, and then apply \u003ca href=\"\/products\/classicbond-epdm-lap-sealant-for-rubber-roofing\"\u003e\u003cstrong\u003eLap Sealant\u003c\/strong\u003e\u003c\/a\u003e along the exposed top edge of the termination bar.\u003c\/p\u003e\n    \u003cp\u003eThis two-stage approach provides:\u003c\/p\u003e\n    \u003col\u003e\n      \u003cli\u003eInternal compression sealing\u003c\/li\u003e\n      \u003cli\u003eExternal weather protection\u003c\/li\u003e\n    \u003c\/ol\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; list-style:none;\"\u003e\n    Application (Overview)\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\u003eEnsure all surfaces are clean and dry\u003c\/li\u003e\n      \u003cli\u003eApply an 11mm bead between substrate and membrane\u003c\/li\u003e\n      \u003cli\u003eInstall termination material\u003c\/li\u003e\n      \u003cli\u003eTighten fixings to create constant compression\u003c\/li\u003e\n    \u003c\/ol\u003e\n    \u003cp\u003e\u003cstrong\u003eCoverage:\u003c\/strong\u003e\u003c\/p\u003e\n    \u003cul\u003e\n      \u003cli\u003eApprox. 3 linear metres per tube at recommended bead size\u003c\/li\u003e\n    \u003c\/ul\u003e\n    \u003cp\u003e⚠️ Not suitable for use on insulation\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; list-style:none;\"\u003e\n    Product Details\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\u003e\n\u003cstrong\u003eProduct:\u003c\/strong\u003e ClassicBond Water Cut-Off Mastic\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eType:\u003c\/strong\u003e Butyl-blend compression sealant\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eColour:\u003c\/strong\u003e Grey\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eService Temperature:\u003c\/strong\u003e -40°C to 93°C\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eCoverage:\u003c\/strong\u003e Approx. 3 linear metres per tube\u003c\/li\u003e\n      \u003cli\u003e\n\u003cstrong\u003eShelf Life:\u003c\/strong\u003e 1 year (unopened)\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; list-style:none;\"\u003e\n    A 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\u003eWater Cut-Off Mastic is what actually seals the fixing penetrations beneath a termination bar. Lap sealant protects the edge - but water cut-off seals underneath.\u003c\/p\u003e\n    \u003cp\u003eUsed correctly, it prevents water tracking through screw holes and protects the roof build-up long-term.\u003c\/p\u003e\n  \u003c\/div\u003e\n\u003c\/details\u003e","brand":"The Flat Roofing Shop","offers":[{"title":"Default Title","offer_id":56518638698827,"sku":"CB-WCM","price":12.22,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0997\/4054\/9451\/files\/water-cut-off-mastic.jpg?v=1773577284","url":"https:\/\/theflatroofingshop.co.uk\/products\/classicbond-epdm-water-cut-off-mastic","provider":"The Flat Roofing Shop","version":"1.0","type":"link"}