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Looking for a 1h+ fire rated wall covering material, moisture proof like cement board

Don J. | Posted in Green Products and Materials on

Dear experts & vendors

I am looking for a ceiling/wall material to safely cover XPS in a ‘wet area’ such as a bathroom.
Is there a material with the properties of type X or C drywall having the durability of cement board combined?

In particular I need fire rating 1h+ and moisture / mold resistance as with cement boards.

Can you recommend various materials I can use to cover XPS with above characteristics so I can install it in a ‘wet’ area indoors as wall panel or ceiling panel?

Thank you

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  1. GBA Editor
    Martin Holladay | | #1

    Don J.,
    Cement backerboard can be used in 1-hour fire-rated assemblies. Here are some links to documents that provide examples:

    Page 5 of this document:

    Page 48 of this document:

    Page 8 of this document:

    Page 9 of this document:

    There are four images attached below. Unfortunately, the GBA software runs all the images together. If you click carefully, however, you can separate and enlarge the four images I have posted.

  2. Don J. | | #2

    Thanks Martin

    I have seen these before but I thought it's actually the gypsum panel adding the fire protection.
    On Hardie's website they say the temp is passed through cement and can't protect the substrate from rising temps.
    Type X & C drywall also won't collapse as fast as cement board when exposed to direct flame.
    I guess that has to do with the fine fiberglass fibers in the cement board. I bet it would have been fine if metal lath had been used

    Are there any other panels that come to mind?

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