2024-25_NTCA_Reference_Manual_dig_dwnld

Backer Boards

Problem

Prevention

Cure

Irregular wall surfaces, bowed out at fix tures/grab bar locations.

Metal straps are installed over studs to provide support for wall hung fixtures, grab bars, etc.

Install supports between studs flush to face of studs to provide a suitable sub strate to cover with tile. Option: When straps are installed over the face of studs, shim the remainder of all studs on the wall prior to the installa tion of backer board to provide a suitable substrate to cover with tile. A. Ensure that the subfloor is adequate to handle the static and dynamic loads expected. B. Properly tape all of the seams in the backerboard if required by manufac turer. C. Follow the fastener spacing and pat terns recommended by the backer board manufacturer.

On horizontal surfaces, the tile is cracked along the seams of the subfloor or the underlayment.

A. The subfloor is inadequate to handle the static and dynamic loads being ap plied. B. Backer board seams not properly taped. C. Fastener spacing and patterns not followed per the recommendation of the backer board manufacturer. D. Subfloor deflection E. Proper spacing between sheets of subfloor not maintained according to manufacturer’s directions. A. No leveling bed underneath the backerboard. B. Fastener spacing and patterns not followed per the recommendation of the backer board manufacturer.

On horizontal surfaces, the tile/grout is cracking and the floor sounds hollow.

Remove and correctly install the backer board: properly laid out, spaced, set in a setting bed and fastened with appro priate fasteners following the manufac turer’s fastening pattern. Fill and tape joints using alkali resistant mesh tape and the dry-set, thin-set adhesive being used to install the tile.

NTCA Reference Manual | 2024 / 2025

Chapter 3 | Backerboards and Underlayments

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