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Exploring EXACOR® MgO Products’ Fire and Sound Rated Panels: An 8-Question FAQ Guide

4 Min Read May 14, 2024

When it comes to multifamily construction, ensuring your build meets code requirements for fire and sound resistance is generally at the top of the checklist. Choosing the best product is a given. EXACOR® MgO products make the choice easy. With EXACOR panel assemblies and less need for other trades, you could eliminate the need for wet-laid gypsum.

1. What are EXACOR® MgO underlayment panels?

EXACOR® MgO (magnesium oxide) panels are cementitious panels primarily made of inorganic materials reinforced with layers of fiberglass mesh. EXACOR MgO underlayment panels are manufactured to provide a streamlined solution for strength, fire resistance, and sound performance when used in approved fire and sound-rated assemblies.

2. Why should I use EXACOR panels?

EXACOR panels can save you time. These panels can help reduce cycle time, reduce the number of on-site trades, be easily installed by existing framing crews and contribute to sound and fire-resistance-rated assemblies following today’s building standards.

Check out some real thoughts and results.

Time is money for a lot of contractors, and you also have the budget part of it, the cost involved with the project. We personally found savings in both categories for us when it comes to using EXACOR as opposed to another fire or sound rated assembly. Jackson Andrews, President of Jackson Andrews, Building & Design

3. How do EXACOR panels reduce cycle time?

EXACOR MgO products can eliminate the cure time of wet-laid gypsum, which reduces cycle times.

4. What trades can EXACOR panels eliminate the need for?

Because EXACOR can be installed by your framing crew, you no longer need specialized crews to install wet-laid gypsum.

5. Can you use EXACOR panels in conjunction with wet-laid gypsum?

It is not recommended to use EXACOR panels with wet-laid gypsum.

6. Can EXACOR underlayment panels be used in any wet-laid gypsum fire-resistance rated assembly?

EXACOR MgO products may only be used with certain fire-resistance rated assemblies and cannot be used with every wet-laid gypsum fire-resistance rated assembly. Check out our tested, evaluated, and approved assemblies.

7. When do I install EXACOR underlayment?

You have two options:

  1. Immediately after the subfloor is installed and before the walls are framed. The walls will be stood on top of the EXACOR panels. This is the primary method since it provides the best installation and cycle time savings.
  2. The panels can be pieced in after the building has been framed (all of the walls are in place) and before the finished flooring installation. The panels are cut and installed around the walls.

See our EXACOR Underlayment Installation Manual for further details.

8. What adhesives are compatible with EXACOR panels?

When installing EXACOR panels, you should use a solvent or polyurethane-based construction adhesive that meets the requirements of APA AFG-01 or ASTM D3498. A good option is always AdvanTech subfloor adhesive.

If you would like more detailed information on this, you can look at our install manual.

9. What is the sound rating of EXACOR panels?

Individual building components don’t frequently have a standalone sound rating. Rather, components such as EXACOR underlayment are used as a part of a sound-rated assembly. Check your local building codes and the EXACOR Sound & Fire Assemblies Handbook for more information.

10. What finished floors can go over EXACOR panels?

Various finished floors can go over EXACOR panels; carpet and pad, natural hardwood flooring, engineered wood flooring and vinyl. Tile cannot be directly installed over EXACOR underlayment. Ensure that you follow the manufacturer’s requirements for installation for each option of finished flooring.

Check our installation manual for more detailed information.

EXACOR Floor Assembly

11. What kind of fasteners are compatible with EXACOR panels?

Corrosion-resistant fasteners should be used with EXACOR panels. The fastener type, size, spacing, and corrosion resistance level depend upon the application. Please see the respective installation manual for your application.

EXACOR Underlayment Installation Manual

EXACOR Wall Sheathing Installation Manual

12. What fire-resistance rated assemblies are available with EXACOR panels?

There are a variety of fire-resistance rated assemblies available with EXACOR. Check out the EXACOR Sound & Fire Assemblies Handbook to see which one suits your build.

To find out how to get EXACOR for your next build, reach out to your local supplier.

For more detailed technical information, check out our technical library or contact