{"product_id":"closed-cell-backer-rod-foam-caulk-saver-for-slab-penetration-sealing","title":"Closed-Cell Backer Rod Foam Caulk Saver for Slab \u0026 Penetration Sealing","description":"\u003ch3\u003eThe backer mitigators use under RadonAway Pro Sealant\u003c\/h3\u003e\u003cp\u003eClosed-cell polyester foam backer rod for sealing the gaps that radon mitigation actually encounters: 4\" PVC pipe through an oversized cored hole, foundation hairline cracks, sump-pit perimeters, and sub-slab depressurization air-leak points. Compresses to fill the gap, doesn't absorb water, and gives the polyurethane sealant a controlled depth to bond against.\u003c\/p\u003e\u003ch3\u003eWhy closed-cell vs. open-cell\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eClosed-cell\u003c\/strong\u003e doesn't absorb water — critical for damp basements and sub-slab work where moisture is present\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eClosed-cell\u003c\/strong\u003e doesn't compress under sealant cure — so the sealant joint actually achieves the joint depth specified by ANSI\/AARST\u003c\/li\u003e\n\u003cli\u003eOpen-cell rod (often sold as cheaper substitute) swells in moisture and fails airtight seal over time — not what you want behind a mitigation system\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eSpecifications (all sizes)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eLength:\u003c\/strong\u003e 59 ft (18 m) per roll\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Closed-cell polyester foam, grey\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWaterproof:\u003c\/strong\u003e Yes — non-absorbent, won't wick moisture\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaximum gap fill:\u003c\/strong\u003e 1.5\" (depending on rod size and joint depth)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFlexible:\u003c\/strong\u003e Bends and twists to follow irregular gap geometry\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eChoosing your size\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003e3\/8\":\u003c\/strong\u003e Tight hairline cracks, narrow expansion joints, slab-edge gaps\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e1\/2\":\u003c\/strong\u003e Standard slab crack work, most pipe-to-concrete penetrations under SlabCollar\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e5\/8\":\u003c\/strong\u003e Medium gaps around oversized cored holes for 4\" Sch 40 PVC\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003e3\/4\":\u003c\/strong\u003e Large gaps, sump-pit perimeters, foundation-to-floor expansion joints\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eInstallation\u003c\/h3\u003e\u003col\u003e\n\u003cli\u003ePre-clean the gap of dust and debris\u003c\/li\u003e\n\u003cli\u003ePress backer rod into the gap to the recommended depth (typically half the gap width below the surface)\u003c\/li\u003e\n\u003cli\u003eApply \u003ca href=\"\/products\/radonaway-pro-hybrid-sealant-polyurethane-limestone\"\u003eRadonAway Pro Sealant\u003c\/a\u003e over the backer rod, tooling to a smooth surface\u003c\/li\u003e\n\u003cli\u003eAllow polyurethane sealant cure time per manufacturer instructions before activating fan\u003c\/li\u003e\n\u003c\/ol\u003e\u003cp\u003eFor penetration sealing where a flanged EPDM gasket is appropriate, see \u003ca href=\"\/products\/slabcollar-4-inch-radon-pipe-seal\"\u003eSlabCollar 4\" EPDM Seal\u003c\/a\u003e instead of backer rod + sealant.\u003c\/p\u003e","brand":"RadonDepot","offers":[{"title":"3\/8 inch","offer_id":48607272829183,"sku":"RD-BACKER-38","price":37.79,"currency_code":"CAD","in_stock":true},{"title":"1\/2 inch","offer_id":48607272861951,"sku":"RD-BACKER-12","price":36.39,"currency_code":"CAD","in_stock":true},{"title":"5\/8 inch","offer_id":48607272894719,"sku":"RD-BACKER-58","price":51.79,"currency_code":"CAD","in_stock":true},{"title":"3\/4 inch","offer_id":48607272927487,"sku":"RD-BACKER-34","price":55.99,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0793\/6639\/0015\/files\/81dkDy9bE9L._SL1500.jpg?v=1780175478","url":"https:\/\/radondepot.ca\/products\/closed-cell-backer-rod-foam-caulk-saver-for-slab-penetration-sealing","provider":"Radon Depot","version":"1.0","type":"link"}