CeraZorb Underlayment

CeraZorb Underlayment

Starting from $199.00 19 Reviews

  • Heat and cold resistant, and will not rot, support mold and mildew, or absorb moisture.
  • Stable and durable, remaining unchanged after repeated impact loads.
  • CeraZorb® has a 1.5 R-value, and it offers crack isolation of up to ¼”.
  • Lightweight, up to 25 times lighter than 1/4” backer board, and weighs in at only 28 lbs. per each 400 sq. ft. box.
  • Can be set under tile and stone, over any acceptable sub floor.


CeraZorb is a synthetic cork underlayment that is installed on top of a subfloor and below a heating element. It is recommended when installing an electric floor heating system over a concrete slab to prevent heat loss. By creating a thermal break, the heat is prevented from sinking into the concrete, and more heat radiates into the floor covering and room. In addition to preventing unnecessary heat loss, CeraZorb provides sound dampening benefits and double the crack isolation benefits when compared to cork.

CeraZorb is lightweight—up to 25 times lighter than traditional 1/4" backer board. It is available in 2’ x 2’ and 4’ x 4’ sheets, and in packs of 12 and 25 sheets, respectively. CeraZorb is a 5 mm. (roughly 3/16 in.) thick, synthetic cork underlayment system that is specifically designed for setting tile and stone and is an excellent insulation choice under our TempZone™ electric radiant floor-heating product. It’s a very resilient underlayment with compressive strength of 34 psi at 10% deformation. 

CeraZorb comes with a 5-year limited warranty

Customer Reviews

CeraZorb Underlayment achieved an average rating of 4.9 stars with 19 reviews by our customers.

Just enough insulation from slab.

Kelly C., Biloxi, MS on 02/25/2019

Product minimizes heat loss from concrete slab on cold days. Product was grouted down first and then the element rolled out. Great at minimizing thickness of completed floor!

Works surprisingly well

Andrea B., Brattleboro, VT on 02/01/2019

I'll admit, when this arrived I was doubtful that it would do anything - it's pretty thin. But halfway through the CeraZorb underlayment installation on the basement floor, we could feel it working - definitely blocked the chill coming through the concrete! I'm certain this will keep the radiant floor heating in the room where it belongs, and not seeping down into the concrete below.

Great product

CNR G., PASSAIC, NJ on 05/14/2017

Great product, fast shipping

Great product

Tim O., BELLEVILLE, IL on 02/03/2017

Great product, would highly recommend if you are putting a heated floor over a concrete basement floor. They are pricey though if you need a lot.

Great Protection and Resistance

Mike T., Fishers, IN on 01/08/2017

This product was easy to install and added great protection and resistance between the slab an the heated floor.

I will be using this system on all future jobs

Bruce A., WOODCLIFF LAKE, NJ on 11/03/2016

Great product with exceptional customer service. I will be using this system on all future jobs.

Very impressed

Graeme H., EDMONTON, AB on 09/07/2016

Very impressed with the insulation value of these tiles especially for being only 5 mm thick.


Robert S., AVERILL PARK, NY on 04/18/2016

This product is great. My radiant flooring grid would not have worked AT ALL if I hadn't used your CeraZorb mats. I tested the insulation properties by standing barefoot on my cold concrete floor. Then I stood on your product & the difference was AMAZING. I felt absolutely NONE of the coldness of the concrete. Thank you for coming up with this underlayment!

Quick warmth!

Kathie S., Punta Gorda, FL on 04/16/2016

I'm sure the cork is in large part responsible for my tile floor warming up so quickly!

Excellent product. Easy to use and seems to work very well.

Cathy R., Stoughton, WI on 04/16/2016

Excellent product.

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