There is no need to install backer board on a concrete substrate ceramic tile can be applied right over concrete provided the surface is flat smooth and free of significant cracks.
How to install backer board to concrete floor.
Next place a sheet of the backer board over the wet adhesive.
For highly wet areas such as showers and bathtub surrounds cement board typically is attached directly over the wall studs and the studs may be covered with an intervening moisture membrane.
Remember that it is best when joints in the backer board are not aligned with the joints in the subfloor.
You are only cutting through the fiberglass mesh on the surface.
Cement board screws spaced every 4 in.
Notched trowel and use the notched edge to comb the mortar.
Do a dry run and lay the backerboard down to fully cover the area you plan to tile.
These convenient panels of cementitious board provide an instant flat hard surface that bonds with the thin set adhesives or mortars used to install tile.
Bc plywood over the old subfloor using construction adhesive and driving 1 1 4 in.
Precut and fit all the cement board and then lift all of the cement boards out.
The plywood adds stiffness and stability to the floor.
Use a chalk line to mark the dimension of the backer board sheets onto the floor.
Measure and cut the cement board to fit in around the whole sheets.
Add more mortar as necessary to fill sunken areas in.
Plan so the joints in the backerboard won t line up with the joints in the subfloor.
Leave 1 8 inch between sheets and cuts.
Screws every 6 in.
With the plywood in place install the backer board as you normally would.
Spread the mortar to about 3 16 thickness.
With the straight edge in place over your mark cut through the surface of the board with the knife.
Embed the cement board and screw it to the underlayment with special 1 1 4 in.
The backerboard should completely cover the subfloor joints.
Plan the placement of the cement backerboard sheets.
Then spread thinset mortar with the flat side of a 1 4 in.
Lay the backer board according to the manufacturer s instructions.
Mark the cut on the cement board using the straight edge and pencil.
Using a notched trowel apply a leveling bed of thinset mortar over the subfloor and embed the backer board sheets into the adhesive.