CeraZorb HD Synthetic Cork Insulating Underlayment 5mm
CeraZorb HD is a 5mm synthetic cork insulating underlayment designed to install beneath ceramic tile, natural stone, and click LVT floor coverings — including LuxHeat electric floor heating mats and cables.
Its primary function is thermal: by placing an insulating floor underlayment between the heating element and the cold subfloor, CeraZorb directs heat upward toward the tile surface rather than letting it dissipate into the slab or framing below. The result is a radiant floor heating system that reaches set temperature faster, holds it more consistently, and costs less to run from day one.
Unlike natural cork, CeraZorb HD's synthetic cork composition does not rot, absorb moisture, or support mold and mildew growth — making it suitable for use in bathrooms, kitchens, and any moisture-adjacent installation. It is up to 25 times lighter than ¼" cement backer board, and its 5mm (3/16") profile keeps floor height gain minimal. Panels install in a 2'×2' and 2'×4' format and require no special tools to cut and lay.
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Insulating underlayment that reduces heat loss — thermal barrier between heating cables and cold subfloor maximizes upward heat output; makes any LuxHeat system more responsive and energy efficient
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5mm (3/16") synthetic cork underlayment — the ideal thickness to balance thermal performance with minimal floor height increase; CeraZorb synthetic cork is purpose-built for tile and stone installations
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Mold and moisture resistant — synthetic cork insulating underlay will not rot, absorb water, or support mold or mildew growth; safe for wet-adjacent areas
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Robinson test Light Commercial Rating — cork underlayment for tile passes structural performance requirements for residential and light commercial tile and stone installations
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Up to 25× lighter than ¼" backer board — fast and easy to handle, cut, and install; reduces physical labor on large projects
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Acoustic and crack suppression — adds sound dampening between floors and a cushioned base that helps absorb minor subfloor movement
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Available 20–400 sq ft — in 2'×2' and 2'×4' panel formats to match any room size and minimize cutting waste
Pair CeraZorb HD with a LuxHeat floor heating mat or cable kit to maximize system efficiency. Free shipping on all orders within the contiguous US.
Frequently Asked Questions
Can CeraZorb HD be used without a radiant floor heating system?
Yes. CeraZorb HD works as a stand-alone insulating floor underlayment beneath ceramic tile, natural stone, or click LVT even without any heating cables. It still delivers thermal insulation (making cold tile floors noticeably warmer in winter), acoustic dampening, and crack suppression benefits — all from a single 5mm underlayment layer. It is not limited to radiant heating installations.
Does CeraZorb HD replace cement backer board or a waterproofing membrane?
No — CeraZorb HD is a thermal insulating underlayment, not a structural backer board or waterproofing membrane. It installs between the subfloor and tile assembly to improve thermal efficiency and add acoustic insulation. For installations that require a waterproof substrate — such as showers or wet rooms — use PROVA Board Plus+ as your backer board. CeraZorb HD is intended for dry or semi-dry tile installations over a properly prepared subfloor.