QA

Question: How To Lay Backer Board

Introduction. Check the Area. Lay the Backer Board. Lay the backer board in a “brickwork” type pattern–meaning that sheets are offset. Apply the Mortar. Using a notched trowel, apply a leveling bed of thinset mortar over the subfloor and embed the backer board sheets into the adhesive.

Do you have to use thinset under backer board?

Using thinset under cement board is a commonly skipped step amongst many contractors. However, many manufacturers including, both Durock and Hardiebacker not only recommend that you use thinset under their backerboard, but they specify it and will void the warranty on their product if it’s not used.

Do you have to screw down backer board?

Screw and Joints All of your backer board pieces should be cut before they are placed on​ the floor. Along the perimeter, screws should be installed at least ½ inch from the edge, but no more than 2 1/4 inches. It is important to highlight that screws shall not be installed all the way down to the floor joists.

Does it matter which way you lay cement board?

No, it doesn’t matter. Regardless of which side faces out during installation, you can expect the same great performance that has made USG Durock® Brand Cement Board the preferred choice of professionals and do-it-yourselfers for decades.

How thick should thinset be under Backerboard?

How much thickness will thinset add? The thin set under the backer board may account for about 1/16″. The bond coat for the tiles about 3/32 – 1/8″. Your best bet is to use 1/4″ which should end up being 5/16″, standard thickness tiles can average about 3/8″ installed, plus or minus.

Can you install cement board without thinset?

Installing cement board over a concrete subfloor. Not only is thinset a critical component underneath cement board but the other critical component is the fasteners. And you won’t have the fasteners if you are trying to install it over concrete.

Do you have to tape backer board seams?

For tile backer boards such as Durock, Wonderboard, Hardiebacker, Permabase, and others the seams between the board need to be treated with 2-inch alkali-resistant mesh tape. It helps to make the walls that are to be tile more monolithic.

Which side of cement board faces out?

Cement board has a smooth side and a rough side. Face the rough side out if you will be using thin-set mortar adhesive to install the tile but the smooth side out if you will be using latex mastic.

What do you do with a gap between tub and cement board?

Ideally, you would leave a 1/8 inch gap which would then have the sealant applied to it. Either stopping the cement board above the tub flange or alternately shimming it out and dropping it down near the tub would both be good options.

How long before you can walk on backer board?

However, after you mount the backer board to the floor you simply have to seal the seams with mortar and wait until the mortar dries. This is normally 12 hours but may be up to 24 hours in some cases. After the mortar is dry the backer board is ready to receive the mortar for the tile.

Can you tile directly on cement board?

Cement board forms a durable, stable base for tile, and it has no organic materials (unlike drywall, greenboard, or plywood) so it is not prone to mold, rot, shrinkage, or decomposition due to moisture. Ceramic tile laid over cement board is one of the most durable floor or wall surfaces you can install.

Do I need to seal cement board before tiling?

Contrary to popular thought, tile and grout are not waterproof, and some moisture will penetrate even if sealant is used. However, if you choose to use concrete backerboard, which is much stronger and more durable than gypsum board, a water vapor membrane must be placed underneath it or a sealant applied on top of it.

Can I use drywall screws for cement board?

You don’t want to use regular drywall screws for cement boards. They can corrode, they can break down the edges of the boards, and they won’t drive in flush properly. Use ITW’s ROCK-ON and BACKER-ON screws instead.

What kind of thinset goes under cement board?

An unmodified thinset (Masterblend) is fine between the Hardi and the subfloor. Tara, The reason for the layer of thinset between the cement board and the subfloor is to fill the voids/gaps between the two. It’ll keep the cement board from moving up and down.

Can I put thinset on plywood?

Thinset is the wet base that you first trowel on the plywood to make the tile stick. Higher latex content is essential for bonding to plywood. A quality unmodified thinset should be used and mixed with a latex additive.7 days ago.

Do you put mortar under cement board?

Spread Mortar Use thin-set mortar when installing cement backerboard. Thin-set dries slowly, allowing you to fix and readjust backerboard sheets as needed. (Thin-set mortar ingredients are cement, fine sand and a water retaining agent. It’s used to bond ceramic or porcelain tile and cement backerboard.).

Can you use Liquid Nails on cement board?

Can I use liquid nails or glue with HardieBacker® cement board? No. ”Liquid Nails” is not a bonding mortar. It is a structural adhesive generally used to bond the subfloor to the floor joists just prior to nailing.

How do you fill gap between cement board and drywall?

Fill the gap between the boards with mortar using the 6-inch taping knife. Force it into the gap and apply a thin layer on both sides of the joint for a total width of 3 to 4 inches. Place fiberglass mesh tape over the entire length of the joint and smooth it with the knife.

Does backer board go under shower pan?

The wallboard must be installed 1/8 inch above the shower pan. If the shower pan is not in place, the wallboard height must be guessed, which can lead to inaccuracies and an expansion gap that is too large or too small.

Can cement board be left in rain?

Most brands of concrete backer-board consist of a fibrous reinforcement cement composition molded into sheets. It is extremely hard and waterproof, meaning it will not deteriorate over time when exposed to water, making it ideal for use in high-traffic areas that are susceptible to the adverse effects of moisture.