Bathroom Floor Tile

[Paul]

On the floor, Cement backerboard or Plywood underlayment?

TIA

[Tom J]

Mine has been down since 1965 on double layers of 3/4 treated plywood and is still solid with no cracked grout, BUT most installations now seem to have a bottom layer of ply and a top layer of backerboard.

Tom J

[Rich]

Paul wrote, wondering if this is really what he meant?

Either or should be fine but the concrete backer board is highly effective.

Rich

[DLGlos]

Either can work, although Cement backerboard is the better choice, especially in an area that will likely get wet. If plywood, you must use an exterior grade (like exterior BC).

That said, go to this site

make sure your subfloor and joists pass maximum deflection requirements for the floor you select. Unlike a lot of pro type sites, the pros on the John Bridge site go out of their way to make certain us DIYer types get it done right.

Note, a ceramic tile floor can handle twice the deflection as a natural stone floor. Also note, backerboard is NOT considered to add ANY strength to the floor, while plywood will.

David Glos

[AnnG]

Simple. 1" thick mortar bed. But for the diy'er, in most cases over a properly constructed subfloor; 1/4" Hardibacker is the ticket. Nix the plywood.