CeraZorb® Insulating Synthetic Cork Underlayment (2’ x 2’) - 48 sq.ft. - Pack of 12 Sheets

CeraZorb® Insulating Synthetic Cork Underlayment (2’ x 2’) - 48 sq.ft. - Pack of 12 Sheets
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  • 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 used under a wide range of floor coverings like tile, stone, LVT, and laminate and can be used over any acceptable subfloor

CeraZorb Underlayment Description

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. CeraZorb is a 6 mm. (less than 1/4 in.) thick, synthetic cork underlayment that is an excellent insulation choice under our TempZone™ or Environ™ electric radiant floor-heating products. It’s a very resilient underlayment with compressive strength of 34 psi at 10% deformation. 

This 12-pack of 2’ x 2’ sheets provides approximately 48 sq. ft. of coverage.


Insulation Specification

Acoustic testing on 6" slab, no ceiling IIC 52 wood construction. FIIC 59 - 7.5" concrete slab. ΔIIC 20 - 6" concrete slab
Compressive Strength 34 psi @ 10% Deformation
Material Hemi-crystalline Thermoplastic
Thermal Insulation 1.5 R-Value


Country of Origin (COO) United States of America

Product Dimensions

Coverage 48 ft²
Depth 0.2362″
Length 24″
Width 24″


UPC (GTIN-12) 881308069964

Warranty / Certifications

TCNA Robinson test Light Commercial
Warranty 5 years

Customer Questions & Answers

CeraZorb Underlayment has 29 Questions and Answers.

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How can I determine what I need for my floor heating project and how can I find out what my floor heating system will cost?

You can use the Instant Quote Tool, which gives you many options for your floor heating coverage. Use this interactive tool to design your room online and receive an instant quotation with product recommendations, rough-in and installation kits, cost of your control, etc. Planning your floor heating project is made easy when using our Instant Quote Tool.

Send us your floor plan or fax it to (800) 408-1100 and we will send you a quote, product recommendation and a free custom installation plan for your project.

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What type of flooring can I install along with an electric floor heating system?

WarmlyYours’ TempZone™ product is most commonly installed under tile, stone, and marble flooring, but can also be installed under many other popular floor covering options such as hardwood, vinyl and linoleum. We also have our Environ system, which is an electric floor heating product as well and is specially designed for installation under carpet (in the U.S. only), laminate and floating wood. WarmlyYours can accommodate any flooring type with either of the electric radiant floor heating products that we offer. If your flooring type isn't listed here, just give us a call at (800) 875-5285 and we will be happy to discuss it with you.

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Should I add insulation before installing electric floor heating and how will that affect the system's performance?

When installing electric floor heating over a concrete slab, an insulating underlayment like CeraZorb is highly recommended to ensure efficient operation, faster heating times and warmer floor temperatures.

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How do I know if I am installing my electric floor heating system properly?

Please keep in mind that you must check your electric floor heating system with a digital ohmmeter in conjunction with a Circuit Check™. Take an initial reading as soon as you take the product out of the box to verify that it is within -5% / +10% of the values stated on the product’s label. This will give you a basis of comparison for future readings. Take a second reading once you have positioned the system to match your custom installation plan. It is also advisable to take an additional reading in the middle of the tile installation, just to make sure that the Circuit Check™ is doing its job. Then, take a final reading when you are finished with the floor installation and are ready to hook up the thermostat.

The Circuit Check™ is a tool developed by WarmlyYours to give you peace of mind and ensure trouble-free installations. Simply hook up the cold leads to the tool while you position the system to match your custom installation plan.

The Circuit Check™ will continuously monitor the continuity of the circuit during the installation of your system and during the installation of your flooring. The Circuit Check™ beeps immediately when a short in the system is detected, alerting you to a potentially damaged cable in the area you are working, before you lay the tile over the electric floor heating system.
 The WarmlyYours technical support team is available 24/7 to provide assistance if the alarm sounds, or if you would have any questions during your installation.

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Can I use electric floor heating as a primary heat source?

Yes, in most cases, an electric floor heating system can be effective as a primary heat source. However, our TempZone™ and Environ™ systems are most commonly used as a secondary heat source, providing floor-to-ceiling radiant heat to any room in your home where you desire more warmth and comfort.

If you are considering electric floor heating for an addition to your home, such as a sunroom where you have no other source of heat, WarmlyYours offers an innovative online tool which calculates approximate heat loss. This tool can help you to determine if a WarmlyYours’ electric radiant floor heating system will provide your desired comfort temperature throughout the year. You can access the Heat Loss Calculator or you can call us at (800) 875-5285 and a Customer Service Representative will make the calculation for you.

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Customer Reviews

CeraZorb Underlayment achieved an average rating of 5.0 stars with 10 reviews by our customers.

Have you used this product before? Leave a review

These are a no brainer for use on a concrete floor, super eas

Kevin R., Yorkton, SK on 04/15/2023

These are a no brainer for use on a concrete floor, super easy to install.


Anonymous, Frazier Park, CA on 01/30/2023

This product is amazing. We did not have the budget for a heated floor, but wanted something to lower our heat loss from a portion of our home that is on a slab. CeraZorb is impressive with what it accomplishes. A dramatic reduction in heat loss. We wish we installed it throughout the entire house..

Jenn West is a Super Star Account Rep!

John A., Atlanta, GA on 01/03/2023

If I were hiring account reps right now, I'd be thinking about Jenn. She always puts the customer first and tries to think through their needs. Jenn introduced me to the cerasorb product as she listened to me describe my project and prompted me with questions regarding the situational aspects of the installation that helped me, as a homeowner and purchaser, and my installer to come up with a better solution.

great customer service

Terry D., Lake Zurich, IL on 10/29/2022

Shopped around at big hardware stores but WarmlyYours offered a greater selection and terrific customer service. They were very responsive to questions, and helped me with an exchange when my original purchase was slightly oversized for our sunroom. They were also helpful with my contractor handling questions he had about the installation. The radiant heat in our sunroom floor has made the space so enjoyable during this cool fall season.

Best customer service

Frieler I., Sarasota, FL on 10/04/2022

I ordered WarmlyYours for a client of ours and she just moved into the home we renovated for her. She loves the fact that she stay toasty warm in the bathroom.

Great customer service

Peter M., Oak Ridge, NJ on 07/08/2022

Great customer service

Caring staff

Anonymous, Mt Pleasant, IA on 06/02/2022

They verified my order before I ordered the products so i got what I needed. Speedy delivery as well

Great service

Matt R., Lake Zurich, IL on 05/26/2022

I’ve been trying to find an easy way to warm up my son’s bedroom above garage, when I came across WarmlyYours. The radiant heating system was designed by WarmlyYours and installed underneath our new carpet. The whole process was great. We couldn’t be happier. It looks and works great. Thank you.

Great product great service

Bob C., Los Osos, CA on 03/16/2022

We have been working with WarmlyYours for over 20 years and they have provided great products and timely responses. They will service you well.

Great sales guy!

Pete S., Fitchburg, MA on 01/28/2022

Justin really went out of his way to get me what I needed in a timely manner. Very patient and knowledgeable guy.

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