Installation of cement backerboard is always preceded by application of thinset mortar which fills low spots in the subfloor and anchors the backer board sheets.
Installing backer board on floor for tiling.
Installing backer board involves three main steps.
Never install new tiles over existing tiles or onto an unprotected wood or plywood floor.
Half inch cement backer board is ideal for most tiling jobs including walls floors countertops and ceilings.
Unlike wood or drywall sub surfaces cement backerboard will not rot warp or grow mold and mildew when exposed to water.
Its made from cement and sand and is reinforced by fiberglass mats on both sides so it s impervious to water.
Lay the backer board according to the manufacturer s instructions.
Cement board commonly sold under trade names such as durock hardiebacker and wonderboard is now the standard underlayment used for ceramic porcelain or stone tile laid with thinset mortar adhesive cement board is used for most floor tile and has all but replaced plywood and drywall backer materials for wall tile applications in wet areas like showers and tub surrounds.
For flooring the backer board should be installed over a 5 8 inch thick osb or plywood base.
Thick 3 x 5 ft.
For countertops use 3 4 inch plywood beneath the backer board.
Cement board is the most durable trouble free tile backer for tub surrounds showers floors and all other wet areas.
To install ceramic tile over wood the wood surface must be structurally sound enough to support the weight of the tile.
Whenever you re laying tile on a wood subfloor you need to first install cement backerboard to prevent leaks and water damage.
Add more mortar as necessary to fill sunken areas in.
Installing over wood.
Use a trowel to spread the thinset but before you do that be sure you ve scraped off old adhesive from any existing flooring you removed and vacuumed and cleaned well.
Use a polymer modified thin set a type of mortar to attach the backer board to the subfloor.
It s typically available in 1 2 in.
Second the strength of wood boards isn t always consistent.
Spread the mortar to about 3 16 thickness.
According to backer board manufacturers and tile setters installing backer board directly over an old solid wood subfloor is risky for a couple of reasons.
Chipboard cushioned vinyl flooring particle boards of any type oriented strand board osb interior grade plywood tongue and groove planking and hardwood floors are unsuitable substrates for direct installation of ceramic tile.
This provides a solid surface under the tile that prevents flexing that could lead to cracking.
How to install tile backer board.
Install a cement based backer board following the manufacturer s instructions.
Using a notched trowel apply a leveling bed of thinset mortar over the subfloor and embed the backer board sheets into the adhesive.
