Is a vapor barrier necessary behind cement board?

You still need a vapor barrier with cement board, although in this case the barrier can go behind the board. Cement board is heavy enough and breathable enough to take the moisture without a problem. By having the vapor barrier behind the cement board you stop the moisture going further into the wall.

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Considering this, do I need vapor barrier behind Hardibacker?

You need to install a vapor barrier to the studs at the very least, and you must alway mud and tape the seams with fiberglass cement backerboard tape. Backerboard is water-permeable, and will not stop moisture from entering the wall cavity.

should cement board go under tub? You don't need any cement board under the tub. It is far more important to have a sturdy layer of ply under the tub.

Keeping this in consideration, does durock need a vapor barrier?

I called USG,the maker of Durock cement board Next Gen, and they advised using no vapor barrier so that the wall cavity can breath and allow any moisture to evaporate. Their online instructions/diagrams show no use of a vapor barrier.

What do you put behind cement board in shower?

Cement Board and a Liquid Membrane No plastic sheeting goes behind the cement board. A liquid waterproofing membrane, such as RedGard or Hydro Ban, is applied to the cement board and allowed to cure. Then, tile is installed over the membrane.

Related Question Answers

Is Hardie backer waterproof?

cement backer board is not waterproof,but water cant hurt it,even when soaked in water for months or even years

Which side of Hardibacker goes 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.

Should you waterproof cement board?

Concrete backer-board, once commonly referred to in the field by the brand name Wonderboard(r), is a cement product designed as a sheathing material for walls and floors. Most concrete backer-boards on the market today are not water-resistant, but all are waterproof.

Do bathroom walls need vapor barrier?

It is important to make sure that a proper vapor barrier (or vapor retarder) is installed on the walls in your bathroom whenever you're building or remodeling. You don't need to put a vapor barrier in the ceiling of the bathroom.

Do you need green board behind cement board?

Cement board is sometimes called Durock, Wonderboard, and Hardibacker. So, remember green board for damp areas but cement board for all areas that could possible come in direct contact with water to ensure the longest life of your bath and tile needs.

Do I need to waterproof cement board in shower?

“A waterproof membrane or vapor retarder membrane must be specified to prevent moisture intrusion and protect adjacent building materials.” ~B412 Bathtub or shower with prefabricated receptor. Cement board or Fiber-cement board. Consult local building code for moisture barrier requirements.”

What is red Gard?

RedGard® is a liquid-applied elastomeric waterproofing material that cures to form a monolithic membrane. Benefits of Product in the Installation. Easy to use and can be applied by roller, trowel or airless sprayer.

What is the best backer board for a shower?

Tile Backer Board Breakdown

• Foam boards are lightweight, easy to cut, and a completely waterproof. Pictured: Wedi Board tile backer board.
• Schluter approves Kerdi over drywall.
• Hardibacker is the best known fiber cement board.
• Cement board has improved over the years and is easier to work with.

Do you have to waterproof durock?

A moisture barrier is necessary with any cement board product. If you do not have plastic or roofing felt behind it, then a liquid-applied membrane is in order. Durock is indeed waterproof, meaning it is not harmed by water. But it is by no means a barrier to water.

Do I need to waterproof shower walls before tiling?

Prepping for shower tile is different than the prepping for tile on drywall. A shower is considered a wet application, so you need to waterproof the foundation, which you'll learn how to do in these instructions. After the waterproofing step, the instructions are the same as if you were installing tile on drywall.

Do I need to waterproof bathroom floor?

Bathrooms are, by nature, wet spaces. But you want to be sure that water doesn't leak through walls and cause mold or other damage. To avoid leaks and excess moisture build-up, take care to waterproof your bathroom wall, floor and ceiling.

How do you seal a shower before tiling?

Tub or shower wall tile preparation:

1. Apply a layer of 1/2″ thick cement backer board to the wall studs.
2. Tape any seams and corners with fiberglass tape.
3. Apply thin-set adhesive over the fiberglass tape, and allow it to dry.
4. Roll a waterproofing sealer over the walls, and allow the sealer to dry.

Is Thinset waterproof?

Thinset is designed to adhere well in a thin layer that's typically not greater than 3/16″ thick. Although thin-set is not waterproof, it is isn't water soluble. When moisture is present, it will not return to a liquefied state as mastic would.

Can I use deck screws for cement board?

There are screws made for concrete board. Bugle head like drywall screws but they are coated to resist corrosion and have sufficient strength to support the board. The heads are larger than deck screws or drywall screws, too. Rona, HD, HH will all have them.

How much space should be between cement board and tub?

There should be a 1/4" gap between the tub ledge and the backer board. Technically, after the tile is installed over the backer board that gap between it and the tub ledge should be filled with an ASTM C920 sealant (caulking e.g. silicone).

Does subfloor go under bathtub?

Flooring repairs can be intimidating, but the subfloor under the tub generally consists of plywood secured over floor joists and is fairly simple to replace -- once you get access to it. The entire tub unit requires removal before subfloor replacement can begin.

Can you put cement board over drywall?

Because cement board can be used either for floors or walls, the surface below the cement board will vary: In such wet areas, never install cement board directly over drywall or green board. Instead, first, remove the existing surface material, then install the cement board over the studs and membrane, as applicable.

How do you cut cement board?

The simplest way to cut cement backer board is to score the surface and snap the sheet along the scored line, similar to the way you'd cut drywall. In fact, you can use a drywall utility knife to score backer board, but a better option is a carbide-tipped scoring tool.

Does cement board wick water?

If you use cement backer board, you have to install a separate moisture barrier between the board and any wood it's attached to. Since the concrete can absorb and wick moisture, the barrier prevents wood rot if the backer board gets saturated with water.