Best answer

DIY Doctor gets many emails saying that PVA should not be used on walls before they are tiled.

This is simply not true.

...

PVA can be used to seal any type of porous surface,including plasterboard and if it is done properly it will give you a much much better job than working on unsealed walls..

Answered by: Simon Baslé Date created: Jun 23, 2022

Do I need to seal cement board before tiling?

Asked By: Jeffrey Scofield Date created: Jun 20, 2022

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.

Answered By: Gerardo Furtado Date created: Jun 23, 2022

Do you need to waterproof cement board before tiling?

Asked By: Dmitry Streblechenko Date created: Jun 09, 2022

So, if you're looking for durability and strength, concrete backer-board will probably be your choice. First, you should provide a waterproof/resistant membrane against the wood studs before installing the concrete backer-board to protect the wood studs from moisture absorbed through the backer-board.

Answered By: Alan Thompson Date created: Jun 10, 2022

Do you need to tape cement board before tiling?

Asked By: DSM Date created: Jun 10, 2022

2 Answers. The thinset and mesh tape are to strengthen the seams. If you are going to tile over the cement board, you should tape the seams. If you just want to leave the corners untreated that will probably be fine, because that seam won't split the center of a tile.

Answered By: Nick Grealy Date created: Jun 11, 2022

Do you need to plaster plasterboard before painting?

Asked By: M.Viking Date created: Jun 13, 2022

2 Answers from MyBuilder Painters & Decorators Definitely make shure your plasterboard is sealed properly prior to painting. Give the walls a light sand and mistcoat with a mix of Matt emulsion and clean water. There is no difference to painting plaster board to skimmed surfaces.

Answered By: Katriel Date created: Jun 16, 2022

Do you need to prime cement board before tiling?

Asked By: Keith Hill Date created: Jun 17, 2022

Do I need to prime HardieBacker® board before I tile onto it? No. HardieBacker tile backerboard is ready to tile once installed, just wipe down with a damp sponge to remove any dust prior to tiling.

Answered By: Jab Date created: Jun 19, 2022

Can you plaster without PVA?

Asked By: Stephen Quan Date created: Jun 12, 2022

The correct mix for pva for plastering is 1 part pva to 5 parts water, and really only used to stop the plaster drying too quickly, plastering over silk paint with or without pva can only be as adhering as the paint before, pva doesnt make the plaster stick to the behind of a painted surface!

Answered By: Niyaz Date created: Jun 15, 2022

Should a concrete floor be sealed before tiling?

Asked By: frosty Date created: Jun 10, 2022

Concrete sealant or paint prevents the adhesive from sticking properly. You will need to use an acid-based solution, like muriatic acid, to rough up the surface if the top of the concrete is still smooth. Let the surface of the concrete completely dry before installing tile.

Answered By: Krisztián Balla Date created: Jun 11, 2022

Do I need to prime concrete floor before tiling?

Asked By: GOTO 0 Date created: Jun 15, 2022

As a general rule, we would say use a primer of some description to prepare your floor prior to tiling. ... For instance, an old concrete floor that was tiled previously will probably not need a primer, as long as the surface is clean and free from old adhesive and anything else that was stuck to the floor.

Answered By: Slava Vedenin Date created: Jun 18, 2022

Can you tile directly onto plaster board?

Asked By: heltonbiker Date created: Jun 15, 2022

Yes, apply an acrylic based primer such as BAL Primer (undiluted) to the plasterboard with a brush or roller and leave to dry before applying any powered adhesives. All board joints and internal corners should be reinforced using a suitable alkaline joint tape before tiling.

Answered By: GuiFalourd Date created: Jun 15, 2022

Do you have to seal cement board before tiling?

Asked By: SymbolixAU Date created: Jun 19, 2022

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.

Answered By: Moses Koledoye Date created: Jun 22, 2022

Related Question Answers

Betamos

Professor

Do I need to waterproof cement board in shower?

Here's what the TCNA handbook has to say about the matter: “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.

Hanfei Sun

Professor

Do I need to seal my concrete floor before tiling?

Although you don't need to install an underlayment between the concrete and the tile, you need to prepare the surface before placing the tile. After all, cracks and uneven areas in the concrete can cause damage to the tile above, and uncontrolled moisture in the concrete can destroy the mortar and loosen the tiles.

BrenBarn

Professor

Can I use PVA to seal plaster before painting?

Do not use PVA. There are two methods to sealing the new plaster. Firstly, you can use a mist coat of white watered down emulsion. However, it is more preferable to use a primer or top coat and water down the first layer by 10%.

jh314

Professor

Do you need plastic behind cement board?

Their online instructions/diagrams show no use of a vapor barrier. You should, so that any moisture that gets behind the cement board runs into the tub or shower instead of into your wall cavity (causing rot or mold/mildew).

Nicola Peluchetti

Professional

Does adding PVA to cement make it waterproof?

PVA can be added to a cement mortar mix to give the mix a) slightly better waterproofing qualities and b) advanced adhesion to the surface it is applied to. Painting a coat of PVA on the surface before the cement mortar is applied can even further increase this adhesion.

Tomas Kubes

Professional

Do you need a vapor barrier 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.

Bastien Ducreux

Professional

Do you need green board behind cement board?

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.

Blackbam

Professional

Do you need to put a vapor barrier behind cement board?

You should NOT place a vapor barrier BEHIND the backer board. Where, pray tell, would any such collected vapor/water go? Answer:There's nowhere proper for such moisture to egress. The current best practice is to place waterproofing OVER the backetboard and just UNDER the tile.

Jack J Jun - MSFT

Professional

Does cement board have to be waterproofed?

So, if you're looking for durability and strength, concrete backer-board will probably be your choice. ... First, you should provide a waterproof/resistant membrane against the wood studs before installing the concrete backer-board to protect the wood studs from moisture absorbed through the backer-board.

James Lawruk

User

Can I plaster without PVA?

even if the plaster is good,you still need pva,the purpose of pva,is not only for the plaster to stick better to the wall,but also to stop the surface its going on sucking the water out the plaster to quick,stops its cracking and give you more time to work with the plaster.

davidgyoung

User

Can you plaster on wet bonding?

You can plaster on to your base coat as soon as it has stiffened up, does not need to be dry. Make sure any loose plaster and paint is removed from wall and any dirt or grime too, before PVA is applied.

George Stocker

User

Can you put ceramic tile over concrete outside?

For an outdoor tile patio installation to be successful, it needs a solid base, and a concrete slab is an excellent choice. ... If you already have a slab in place, that will save you some work. But before you can start tiling over this base, you need to examine it more closely.

Neil W

User

How do you attach cement board to concrete wall?

Fasten the board to the wall with 2-inch concrete screws and a hammer-action power drill with a Phillips-head screwdriver bit. Activate the hammer action on the drill before driving the screws through the board and into the wall. This is usually accomplished by flipping a toggle or switch or turning a dial.

quervernetzt

User

Can you seal new plaster with PVA?

Applying a mist coat will sufficiently seal your new plaster after it has dried. Many professional painters do not recommend using PVA glue to seal your plaster, as it can cause issues later on. The paint that you then apply afterwards is likely to sit on top of the PVA if you use this method.19 Aug 2019

riQQ

Guest

Can you use PVA on new plaster before painting?

Preparing Plaster To Paint: Seal The New Plaster Before painting the new plaster you will require a sealer to prime the surface. Contractors often worryingly think PVA will work as a sealer. Do not use PVA. ... This allows the initial coat to properly soak into the plaster aiding adhesion of the final coat.

sathishk2030

Guest

Do I need to plaster bathroom before tiling?

Tiling on plaster is ok, as long as your not fitting large format tiles. Still prime the plaster (obviously when dry) with acrylic primer. NOT PVA. Why plaster though.....not really necessary.

Stefan Francis

Guest

Do I need to plaster before tiling?

If you sort the plasterboard out level/flat.........you don't need to plaster it at all....... tile directly onto the plasterboard, because if you are not experienced in plastering, you could end up in a worse state. Sort the plaster board, it's not that heavy.......then prime with acrylic primer.......then tile it.

Pointy

Guest

Do I need to prime cement board before tiling?

Do I need to prime HardieBacker® board before I tile onto it? No. HardieBacker tile backerboard is ready to tile once installed, just wipe down with a damp sponge to remove any dust prior to tiling.

chemamolins

Guest

Do I need to PVA plaster before tiling?

Short answer. No, never use PVA to prime a surface before applying tiles. The acetic acid produced when cement and PVA come into contact would render the adhesive and grout useless. Scroll down for a longer answer!

Peter Olson

Guest

Do I need to sand concrete before staining?

You do not need to sand the concrete before staining unless you are using Acid Stains and the surface to be acid stained is not capable of absorbing liquids..

Andreas Grech

Guest

Do poured concrete walls need insulation?

Do Concrete Walls Need to Be Insulated? Some contractors add foam insulation in the concrete form before pouring the cement while others add rigid board-type insulation on the exterior of the concrete after it hardens. However your basement walls are constructed, you'll likely want to insulate them.

kojiro

Guest

Do you have to prime plaster before tiling?

If your wall has been plastered recently, make sure it has been left for at least 14 days before tiling on new plaster. If this isn't necessary, a coating of sealing primer directly on the plaster will ensure a decent base, just make sure you give it 24 hours to dry.

Alex K.

Guest

Do you have to replace cement board under tile?

Undamaged cement backer board does not need to be replaced.

...

It is difficult to remove tile from a cement backer board, and even more difficult to avoid damaging the board in the process.

Since backer board is relatively inexpensive, it's not normally worth the time and labor it would take to remove the tile to save it..

Aaron

Guest

Do you need plywood under cement board?

The Surface Below the Cement Board Flooring: For ceramic tile floors, the cement board usually rests on a plywood subfloor (minimum 5/8-inch-thick exterior-grade plywood or OSB). ... In such wet areas, never install cement board directly over drywall or green board.

devnull

Guest

Do you need Thinset under cement board?

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..

Nathan Osman

Guest

Do you need to seal plaster before tiling?

Yes, the plaster needs to be sealed as it is very porous and will suck the moisture out of the tile adhesive before it has time to 'grab' properly.

michael.hor257k

Guest

Does cement board need to be sealed?

While you don't always need to seal backer board, it sometimes make sense to do so. If you are installing backer board in an area that will be subject to a great amount of moisture, like in a shower, then it makes sense to put a waterproofing sealer on it.

Mauvis Ledford

Guest

How do you lay porcelain tile on a concrete patio?

Clean the concrete slab thoroughly before laying tile. Apply a waterproofing membrane, such as RedGard, to the slab before tiling. Use a polymer-modified, dry-set mortar adhesive that's rated for outdoor use. Cover the slab completely with the tile adhesive, and apply it to the back of the tiles as well.

Alister Bulman

Guest

What thickness cement board should I use?

Half-inch cement backer board is ideal for most tiling jobs, including walls, floors, countertops, and ceilings.

For flooring, the backer board should be installed over a 5/8-inch thick OSB or plywood base..

testndtv

Guest

How do I attach concrete board to plywood?

Position each piece of backer board in the thin-set, press in place, and attach using special backer board screws on the spacing recommended by the backer board manufacturer.

Cover the joints in the backer board with fiberglass tape embedded in thin-set adhesive and allow to set before tiling..

bruno077

Guest

Do I need cement board for kitchen backsplash?

But for a tile backsplash, if your wall is good and plumb, without any major ridges or problems, you don't always need to use a backer board, often you can just apply thinset to the walls and put your tiles in place.

Vlad Mihalcea

Guest

Do I need to seal a concrete floor before tiling?

7. Apply the Sealer. After cleaning, patching, and repairing the concrete floor, you'll be ready to seal it. This process creates a protective layer that prevents moisture from seeping through the concrete and into the tile floor.

Divakar

Guest

Should I PVA a concrete floor before tiling?

PVA isn't good, don't use it with any form of tiling... You should seal the floor with a suitable primer that is compatible with the adhesive you buy. i.e. buy Ardex primer for Ardex adhesive, BAL primer for BAL adhesives...

michael.hor257k

Guest

Do I need plywood under cement board?

Because cement board can be used either for floors or walls, the surface below the cement board will vary: Flooring: For ceramic tile floors, the cement board usually rests on a plywood subfloor (minimum 5/8-inch-thick exterior-grade plywood or OSB).

Thorarin

Guest

Should you put a vapor barrier 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.

parliament

Guest

Should you waterproof 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..

Joshua Fox

Guest

What do you use to seal cement board when tiling?

The thin-set is a cement-based powder that you mix with water or latex additive to form a thick paste, which is used to seal the seams in the board and can also be used to set the tile. Finally, you'll need an 8 x 12-ft. piece of 4-mil plastic sheeting and some straight 2x4s.

diEcho

Guest

Can you plaster over bonding the same day?

Bonding about 2-3 hours, but some do leave it to following day before skimming depends on size of area. There is absolutely NO need for PVA when skimming over bonding the same day or the next day.

Lukas Graf

Guest

Can I plaster over mortar?

Plastering is all about practice and timing so very good if you can practice as much as possible first. Regarding the strip, use neat pva (and let it dry) on the brickwork to seal it before you apply the sand and cement to the gap. Once that's dry, pva the new surface and then use your wickes skim stuff.

Shital Shah

Guest

Do you need to seal plaster before painting?

Preparing Plaster To Paint: Seal The New Plaster Before painting the new plaster you will require a sealer to prime the surface. Contractors often worryingly think PVA will work as a sealer. Do not use PVA. PVA is the mortal enemy of paint!

Chamod Dissanayake

Guest

Does plaster need to be primed before painting?

Preparing Plaster To Paint: Seal The New Plaster Before painting the new plaster you will require a sealer to prime the surface. Contractors often worryingly think PVA will work as a sealer. Do not use PVA.

Powers

Guest

Do you have to glue down cement board?

You cannot put a cement backer board over that. You need to put a layer or plywood, minimum 5/8 IIRC, over those boards, then mortar the backer to the plywood. Those 1x8 boards won't give a solid foundation and will flex. Over time, that will cause tile to pop loose or crack.

jessegavin

Guest

Should I plaster before fitting bathroom?

When tiling a bathroom 'floor to ceiling' there is no point in plastering out the boards prior to tiling.In fact, it will reduce the amount of tile weight the plasterboard will hold, and it is advisable to leave fresh plaster to dry for 4 weeks before tiling, ensuring you a very long wait!

valex

Guest

Where do you put cement board in a bathroom?

Cement backer board is mainly used as a sub-surface for tiling. Cement backer board is often used as a tile base on plywood or OSB subfloor. Cement backer board on concrete as a subfloor or underlayment is usually not recommended or needed. In most cases, you can apply tile directly to the concrete.