PVA and Tiling: 7 things you should know

Priming a wall before tiling is a great way to protect the surface from moisture. Tiles are used most commonly in wet areas like bathrooms, kitchen splashes, wet rooms, and showers. Areas that see a large amount of water every day. Priming or sealing these areas before tiling is vital to ensure the longevity of the tiles.

Several different primers can be used for priming a surface before tiling. The selection of a suitable primer depends upon the type of surface you are tiling on. PVA can be used as a primer. However, it has certain limitations. Experts recommend SBR (Styrene Butadiene Rubber) and acrylic primers for priming before tiling.

This article will provide you information about using PVA as a primer over floors and walls and the problems associated with this type of primer. This article will also describe other primer types that experts recommend.

PVA before tiling, some helpful tips:

I do not recommend using PVA for priming walls and floors before tiling. PVA is a synthetic polymer mixed with water and is used primarily as glue rather than a primer. PVA produces acetic acid when it comes in contact with the cement-based adhesive. This acetic acid affects the curing and adhesion properties of adhesives, jeopardizing the integrity of the tiles.

Many adhesives and grouts used for tiling are cement-based. These cementitious materials are alkaline in nature, which means they have a high pH value. Alkali reacts with PVA, which has a lesser pH value, and forms acetic acid when PVA comes in contact with these cement-based adhesives. The curing of adhesive is based on hydration, meaning these adhesives bind chemically to the water. This causes a rise in the pH of the mixture dramatically.

When this mixture makes contact with PVA, the acetic acid produced negates the process of curing and prevents the cement-based adhesive from binding the water needed to harden properly. Acetic acid weakens the water bond in the cement and threatens the integrity of the material. PVA becomes live again when it is exposed to moisture. Thus, using PVA as a primer before tiling can affect the adhesion between the tiles adhesive and the primed surface.

Experts highly recommend acrylic or SBR (Styrene Butadiene Rubber) primers for priming walls and floors before tiling. These primers are not affected by moisture and cement used in the adhesives. These primers are better than PVA primers in the sense that PVA remains soluble in water even after drying. SBR primers can also be used as a protective barrier between the substances that have otherwise adverse effects when they come in contact with each other. The following table shows the type of surface and the primer that is recommended to be used on that particular surface.

Type of Surface	Primer
Concrete	Both Acrylic and SBR can be used over concrete
Anhydrite Screed	The acrylic primer should be used
Plasterboards	SBR primer must be used over plasterboards
Plywood	SBR primer must be used over plywood
Tile Backer Boards	SBR primer must be used over backer boards
Sand Screed	Both acrylic and SBR can be used
Blockwork	The acrylic primer must be used

PVA before tiling a floor, some helpful tips:

In general, priming or sealing the floor before tiling is important. Especially in wet areas like bathrooms, kitchens, and showers. Priming helps to prevent water from seeping into the floor through the tiles. Experts do not recommend PVA primers because they react with cement-based adhesives and affect adhesion and curing. SBR or acrylic primers must be used to prime the floor instead.

Priming the floor with PVA is not the most effective. Polyvinyl Acetate forms acetic acid when it comes in direct contact with water-mixed cement-based adhesives. Most of the adhesives are alkaline in nature with high pH values. Acetic acid formed by PVA hinders the curing of the adhesive and does not allow the adhesive to set properly. The adhesion between the thin-set and the subfloor may get affected if PVA is used as a primer. Tiles may crack or dislocate.

Instead of PVA, SBR or acrylic primers can be used to prime the floor before tiling. These primers are moisture-resistant and alkaline-based. They do not react with cement-based adhesive and allow them to cure and settle completely. Using SBR or acrylic primers can increase the longevity of the tiles.

PVA before tiling a wall, some helpful tips:

To protect a wall against water or moisture, diluted PVA glue can be used as a primer. However, experts do not recommend PVA as it produces acetic acid when it comes in contact with cement-based adhesives, which hinders the curing of the adhesive. SBR or acrylic primers are more suitable products to prime the walls before tiling.

Tiling the wet area is one of the most common ways to seal and protect the walls from moisture. However, if the walls are not primed before tiling, the water may seep into the walls and eventually damage the walls. The best way to prevent moisture from damaging the wall is to seal or prime the wall. You can use a diluted PVA glue mix to prime the wall before tiling.

Step by step guide to PVA before tiling a wall:

Here is a step-by-step guide to applying a diluted PVA mixture onto the wall for priming.

● Step 1: Prepare the mixture

The first step is to prepare a diluted mixture of PVA glue. You can add 1 part of PVA to 4 parts of water. Before applying the mixture to the wall, ensure that PVA has dissolved completely.

● Step 2: Apply the mixture

The next step is to apply the diluted PVA mixture to the wall. Diluted PVA mixtures can be applied directly to the plasterboard or plaster wall with the help of a brush. Allow the mixture to dry for 15-20 minutes after application.

● Step 3: Apply the second coat

After the first coat has dried completely, apply the second coat of the diluted PVA mixture and allow it to dry overnight.

● Step 4: Ready for tiling

After the application of both coats, the wall is completely primed and ready for tiling!

PVA concrete floor before tiling, some helpful tips:

Tiling over concrete in wet areas requires a primer to be applied before installation. PVA is not recommended to be used as a primer over concrete. SBR or other acrylic primers are the best choices to prime the concrete floor prior to tiling.

A primer should be used before installing tiles in a wet room to remove any dust and debris present on the surface. PVA primers are not recommended on concrete floors before tiling. PVA forms an acid when it comes in contact with cementitious adhesive, which hinders adhesive curing. Using PVA as a primer over concrete can affect the adhesion between the thin-set and the primed surface. The tiles may get disturbed and dislocated eventually.

SBR or acrylic primers must be used to prime the concrete floor before tiling. These primers are specifically prepared to work with tile adhesives. SBR is a bonding agent, but it can also be used as a primer and sealer to improve adhesion between successive layers. SBR is better than PVA because PVA remains water-soluble even if it is dry or exposed to moisture.

SBR is moisture-resistant once it is completely dry. That makes it well suited for damp surfaces like washrooms, shower areas, and kitchens. When SBR is used as a sealer, it must be allowed to dry completely. Once it is dried completely, it will lose its adhesive ability and keep its sealant qualities for life.

PVA plasterboard before tiling, some helpful tips:

Most manufacturers recommend the use of a primer on plasterboard before tiling wet areas. If you don’t prime plasterboard before tiling, you may put all your tiling work at risk. PVA (Polyvinyl Acetate) can be used as a primer or to seal the surface. However, most experts do not recommend it. The best way to prime the plasterboard is to coat it with SBR (Styrene Butadiene Rubber).

It is always important to prime the plaster walls in the wet areas before tiling to avoid any problems due to moisture and water. Moisture can damage the plaster over time. Grout is also not water-resistant and can deteriorate over time, letting the water seep into the walls.

PVA can be used to seal subfloors and walls. PVA can also be used as a primer to give extra adhesion. However, experts believe that using PVA primers hinders the adhesive’s curing process, which may affect the settling of the tiles. Tile adhesives crystallize when the adhesive sets. The crystals formed after the adhesive sets expand into the imperfections to create grip. PVA creates a barrier between the substrate and the tiling thin-set and stops the process of crystallizing.

PVA is a high-performance bonding agent, primer, and dust proofer as well. Pour a small amount of water and stir it well before application. PVA is water soluble therefore make sure you don’t over dilute the glue. You should apply at least three coats of undiluted PVA to waterproof the plaster. Allow each coat to dry completely before applying the next one.

SBR primer is the best option to be used to waterproof wet surfaces before tiling. SBR is better than PVA because PVA remains water-soluble even if it is dry or exposed to moisture.

SBR is moisture-resistant once it is completely dry. Wet rooms, shower areas, and kitchen walls and floors must be primed or sealed with SBR. Allow the SBR primer to dry completely after its application. SBR loses its adhesive ability but will keep its sealant qualities for life once it gets dry.

PVA plywood before tiling, some helpful tips:

In general, it is always important to waterproof plywood before tiling to avoid any problems due to moisture and water. Most manufacturers recommend using a primer on plywood prior to tiling. If you don’t waterproof the plywood before tiling, you may put all your tiling work at risk. The best way to waterproof plywood is to coat it with SBR (Styrene Butadiene Rubber) or PVA (Polyvinyl Acetate).

PVA can be used to seal plywood to give it a waterproof quality. PVA can also be used as a primer to allow extra adhesion. It is a high-performance bonding agent, primer, and dust proofer as well. PVA is water-soluble, and you can add water to the glue to make it thinner. Make sure you don’t over dilute the glue, add small amounts of water at a time and stir it well. You should apply at least three coats of undiluted PVA to waterproof the plywood, allowing each coat to dry completely before applying the next one.

SBR can also be used to prime plywood before tiling. SBR is moisture-resistant once it is completely dry. Therefore, it is more suitable for damp surfaces like washroom, shower areas, and kitchen.

PVA wall before tiling, some helpful tips:

In general, moisture and water pose a threat to tiling. It can create cracks in the grout, leading to water seeping into the wall and the deterioration of the tiles over time. For that reason, it is important to seal the walls with a primer, sealant, or by installing moisture-resistant plasterboard before tiling. This prevents moisture or water from damaging the wall and the tiles. PVA can be used to seal the walls; however, it has certain limitations that are discussed below. The best way to prime walls is to use an SBR or acrylic primer.

Priming the walls in wet areas such as bathrooms, showers, and wet rooms is important. You must ensure that your wet room or bathroom is fully waterproof before installing tiles since tile adhesive and grout do not protect against water damage.

Walls can be waterproofed either by sealing their surface with a sealer or primer. SBR and PVA primer can be used for this purpose. PVA primers are water-soluble and become live again when exposed to moisture. This property of PVA can damage the tiles on the wall and will form an acid when it comes in contact with cement-based adhesives. The acid stops the curing process of the adhesive, and the adhesive may not harden properly. This can cause your tiles to fall off the wall eventually.

It is recommended to use SBR or acrylic primers to prime the walls before tiling to be on the safest side. These primers are moisture-resistant and most effectively seal the surface of the wall against moisture.