top of page
  • Joel Bardall

How to fix peeling paint in a bathroom and stop mould

Updated: Sep 9, 2023

A common issue I come across and frequently get asked is ‘how to fix peeling paint in a bathroom and stop black mould appearing?’

It’s not just unsightly and horrible to look at but also black mould is very bad for your health.

First of all, why does it happen?

Simple answer is poor ventilation and moisture that is unable to escape properly. Topped off with incorrect paint products used which all leads to failed paint work and eventually mould.

How do you resolve it?

To begin with, the black mould needs to be taken care of. There are various products available for this such HG mould spray or another mould killing spray by a brand called Zinsser.

And I will be mentioning Zinsser quite a lot in this post because Zinsser is a very well known paint brand in the painting and decorating industry that do a whole range of products including many problem solving primers which I will be discussing throughout this post.

Mould killing spray by Zinsser
Zinsser Mould Killer & Remover

Please do make sure to wear a suitable mask and goggles and even some disposable gloves would be a good idea too prior to carrying out this task.

Spray the affected areas and leave the solution to work its magic. Wipe away with a cloth or disposable cleaning wipe.

You may also come across peeling, flaking and blistering paint. This could all be caused by high moisture content that has damaged the existing paint film or even poor preparation when it was previously painted and the plaster was never sealed properly or / also incorrect paint was applied that could not withstand the conditions and condensation from hot showers etc.

All loose and flaky paint will need to be scrapped off as much as possible until you reach a sound and stable edge of paint. This process will more than likely expose the bare plaster beneath.

If you just try to immediately paint over this without following the next steps, then it will be highly likely to fail once again.

Next step, give the area a good sanding down and wipe away or vacuum any dust residue.

Then (and this is an important step) apply a coat of Zinsser ‘Peel Stop’ to the exposed area that has had the defective paint scraped away from it, making sure to really brush or roll the Peel Stop into the edges of the existing paint work.

Peel Stop is a clear binding primer that acts as a sealer and glue to bind edges of paint to the surface. It is very similar to PVA but what sets it apart is it actually allows the substrate to ‘breathe’.

A can of Zinsser Peel Stop clear binding primer
Zinsser Peel Stop

Once this has dried the area will need to be filled to smooth and even out the surface. Toupret have a fantastic range of fillers and in particular TX 110 quick dry filler would be a good option (there are also a range of ready mixed fillers but would have to allow much longer drying times, up to 24 hours before they can be sanded down)

Once the filler has dried, sand it down as smooth as possible and apply another coat of Zinsser Peel Stop to seal the filler.

A 2KG box of powder Toupret interior quick dry filler
Toupret Quick Dry Filler TX 110

Next I prime the whole surface, so if it is a ceiling I will apply a primer coat over the total surface area.

For this I use Zinsser Bullseye 123. This acts as a base coat for the final finish of paint but also will help to block out any blemishes that could be visible in the top coat and also will help reduce the amount of subsequent coats of paint needed.

A tin of Zinsser bullseye 123 primer sealer
Zinsser Bullseye 123

Please note: If there are stains visible from either mould spores or water stains then a solvent base stain block may be necessary to completely eliminate it from showing through. Zinsser Cover Stain is a great option for this purpose.

My go to paint finish specifically formulated for bathrooms is Zinsser Perma—White. It’s available in matt and a satin finish but I tend to lean towards the matt. The finish is not just fantastic but has anti condensation properties that will stop any unsightly mould from returning. It can also be tinted in colours but would need to search online for a stockist that can do this.

A tin of Zinsser Perma White bathroom and mould resistant paint
Zinsser Perma White matt

If you have followed the previous steps mentioned above then two coats of Perma—White should be sufficient and will produce a lovely crisp clean surface and most importantly will keep it mould free!

Important to keep in mind that the area should have at least 24 hours to dry before using the shower or bath which will produce lots of steam and condensation.

Also ventilation is still a huge factor so an extractor fan, vent or windows opened to allow sufficient airflow during showers, baths etc is definitely recommended.

A Bathroom ceiling after paint scrapped off
Bathroom ceiling after paint scrapped off

Bathroom ceiling after paint scrapped off and sealed with Zinsser Peel Stop
Bathroom ceiling sealed with Zinsser Peel Stop

A Bathroom Ceiling primed with Zinsser Bullseye123
Bathroom Ceiling primed with Zinsser Bullseye123

A Bathroom Ceiling and walls painted with Zinsser Perma White
Bathroom Ceiling and walls painted with Zinsser Perma White

74 views0 comments

Recent Posts

See All


bottom of page