Repairing cement board

Old 04-10-22, 08:18 AM
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Repairing cement board

Installed cement board (hardibacker) for a tube surround. I cut the whole for the valve a little to big. I mounted a piece of cement board on the back side. My question is what material can I use to fill I. The cement board ? Mastic/cement? Or should I replace the cement board? Thanks
Old 04-10-22, 09:00 AM
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I would probably cut a square out of the Hardie back to the centerline of the adjoining studs. That way your repair piece can be securely screwed to the studs. Much the same way you'd do a sheetrock repair. Then if you want you can skim over the joints with thinset to help seal and smooth them.
marksr voted this post useful.

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