How to tile onto a painted wall

Following the advice set out by British Standard it is not recommended to tile onto a papered or painted surface.

BS 5385: Part 1: 2018, the code of practice for internal wall tiling:

“Painted surfaces are generally unsuitable for tiling; a detailed examination of the painted surface should be made to decide whether it is suitable. Emulsion paint, lime-wash, distemper and similar finishes should be removed since they can possess poor adhesion to backing. Solvent based adhesives should not be used”.

Unfortunately, there is no easy fix when it comes to tiling onto an emulsion painted surface, the paint must be removed. Emulsion paint is water based so as soon as the adhesive comes into contact with the paint it reactivates it leaving you with a very poor or non-existent bond.

Additionally, most tiles are now larger than 30cm x 30cm which means a ready mixed adhesive cannot be used and as cementitious based tile adhesives are not recommended on painted surfaces, this leaves no alternative but to remove the paint for larger format tiles.

Removing emulsion paint from plaster can be a difficult and time-consuming process. Holding a wallpaper stripper to the wall to apply steam to the emulsion can often be the easiest way to remove the paint. If you’re having to use a scraper, score crisscrossed lines into the wall with a sharp knife, it makes it much easier for the scraper to get underneath. Collect the emulsion scrapings in a bag while they are still soft, otherwise they can become stuck to the floor or work surface.

Topps’ tip: Removing paint from backgrounds such as plasterboard may damage the paper face of the board. Consider over boarding with a tile backing board such as HardieBacker, in most cases this is a time and labour saving solution.

Once you’ve scraped or steamed away the paint, there may be a surface residue like dirt or grease that prevents your adhesive from sticking to the surface. Use a damp sponge or cloth and a small amount of mild all-purpose cleaner with warm water to remove as much of the residue as possible.

Once the area is clean you will need to key the surface. Keying a surface is done to help your adhesive grip the wall or floor; it creates small, rough grooves that maximise adhesion. The simplest way to create a mechanical key to your surface is by using sandpaper, a sander or scoring it with a knife or scraper. The rougher the surface is when you’re finished, the stronger the tile adhesion will be.

Once you’ve removed the paint and keyed the area you’re most likely to be tiling onto a more porous surface like plaster. When cement-based adhesives meet plaster, a reaction occurs that prevents adhesion and the tilling will most likely fail. Using primers will prevent this reaction.

When using cement-based powdered adhesives, apply two coats of neat BAL Prime APD, BAL Primer or 2 coats of BAL Bond SBR diluted 1:2 with water. When using BAL ready-mixed adhesives, such as BAL White Star Plus, priming is only required if the plaster is very shiny and dusty. If so, brush the surface with a stiff bristle brush and prime with BAL Prime APD or BAL Primer diluted 1:1 with water or BAL Bond SBR diluted 1:4 with water. The primer must be completely dry prior to tiling.

The final stage is choosing the right adhesive for the job. If you’re working with ceramic tiles up to 30cm x 30cm and ensuring the emulsion paint has been removed you can select a ready-mixed adhesive such as BAL White Star Plus.

For tiles greater than 30cm x 30cm tiles and ensuring the all the paint has been removed, tiles can be fixed using a slow-setting, cement-based adhesive such as Excel Bond Slowset Flexible or Kerakoll Biogel No Limits. If a rapid setting adhesive is preferred Excel Bond Rapidset Flexible, BAL Rapid-Flex Fibre Plus or BAL Flex Fibre may be used.

Mix the adhesive in accordance with the mixing instructions on the bag.

Most adhesives are available in either white or grey. Generally, when using a lighter tile or grout you should use a white adhesive, and vice versa.

British Standards recommend that any water sensitive substrate such as plasterboard used in a wet area should be tanked – even if it states it is “waterproof”.

Various methods can be used such as a liquid membrane (BAL Waterproof 1C) or a matting system (Topps Waterproof Matting), either method should be used before tiling.

Following the advice set out by British Standard it is not recommended to tile onto a papered or painted surface however it may be possible to tile onto existing hard gloss paint, backgrounds decorated with hard gloss paint are often sufficiently plumb and securely bonded for tiles to be fixed directly.

Check the integrity of the surface paint, if the paint is not stuck to the wall, it will simply peel away. Always test the painted surface to decide whether the adhesion of the coating is suitable, if in doubt it should be stripped.

The simplest way to test how well the paint is holding is to stick some strong tape, like duct tape to the wall. If any gloss paint comes away with the tape, the wall will need scraping. Remove loose paint with a sander or scraper before wiping away any remaining flecks with a sponge and warm water.

Whether you’ve scraped away the paint or not, there may be surface residue like dirt or grease that prevents your adhesive from sticking to the surface. Use a damp sponge or cloth and a small amount of mild all-purpose cleaner with warm water to remove as much of the residue as possible.

Once the area is clean and dry you will need to key the surface. Keying a surface is done to help your adhesive grip the wall, it creates small, rough patches that maximise adhesion. The simplest way to create a mechanical key to your surface is by scoring it with a knife or scraper.

When you’re working with ceramic tiles of up to 30cm x 30cm you can select standard ready-mixed adhesives, like BAL White Star Plus. You must leave the adhesive to dry for a minimum of three days before grouting as drying times will be extended when tiling onto gloss paint.

For tiles greater than 30cm x 30cm a cementitious based tile adhesive is required but are not suitable for use on any painted surface, therefore if your tiles are over 30cm x 30cm you will need to strip the paint off before tiling.

For any additional advice please contact your local store or Customer Care.