How To Treat Damp Walls Before Painting: 7 Top Tips

how to treat damp walls before painting

How to treat damp walls before painting is a common conundrum for home owners. 

Damp walls are an extremely habitual problem in homes, especially those that reside near the coast or have an inherent damp problem.

Whilst it can be alarming when this is identified in a survey of a home you are purchasing, or you are starting to see black mould or damp patches develop in your home it’s best to act on this immediately before it gets any worse.

If you’re looking to paint straight over the damp for that ‘out of sight, out of mind’ feeling, stop. 

Damp will continue to permeate anything on the walls, and continuing to cover it in more layers will actually make the problem worse as it won’t be able to breathe. 

How to treat damp walls before painting is one of the most commonly asked DIY questions on Google, so if you’re reading this now, so are many other home owners. The good news is that if you follow some key steps you can ensure a smooth, damp free finish on your interior walls. 

How To Treat Damp Walls Before Painting

1.Find The Source of Damp

Unfortunately this is the only way that you can guarantee that the damp will not permeate through new coats of paint. 

It’s something you need to be able to identify to stop the issue causing internal damage too. 

There are many different things that can cause damp which makes it one of the hardest things to treat.

On some occasions the reason can be obvious. Blocked gutters can be a common problem where damp follows the pipe on the inside of the walls, simply getting the gutters cleared out and allowing the damp interior walls to breathe as the damp dries out is a simple solution. 

However, damp can be a much harder problem to identify, it could be caused by damaged exterior walls, crumbling plaster, condensation and poor ventilation, rising damp, the house might not have a damp proofing treatment, there could be a leak, among many other issues. If there isn’t a tell tale reason for the damp, get professional help or a more in-depth survey of the property carried out. 

Whilst there are different types of damp, excess moisture and poor ventilation is one of the most common causes of damp in properties, especially terraced houses and those on the coast. The good news is that there are many ways to tackle this unwanted moisture in your home which is contributing to the damp issues. The best place to start is drying out the walls.

damp In terrace house

2. Dry Out The Walls

Once you have identified and solved the issue of damp, you need to allow the walls to dry out. 

If the area has been damp for a while it will take slightly longer to dry out. There is no point painting until then as the damp stain will continue to permeate through paint. You may want to use a dehumidifier to speed up this process, it can usually take a few weeks to dry out adequately enough. It’s worth noting that if the problem is being caused by a lack of ventilation then a dehumidifier will be a temporary solution to the problem.

A condensation problem can be tackled in various other ways that will give more longevity to the finished results. Whilst opening windows regularly even throughout the winter can help, it doesn’t forcefully take out the wet air. Things you can do to help are to stop drying your washing indoors, adding moisture collectors to windows and if you want a more concrete solution you should look at more long lasting ventilation solutions that can carry a hefty price tag.


3. Wash The Walls

If the walls have been damp for a period of time it’s likely that they will have developed damp stains, or even mould spores over this time. 

It might look daunting, but damp and mould marks can easily be wiped clean. Use a good damp remover spray or something more basic like elbow grease on the affected area and use a clean, damp cloth to wipe the entire wall. 

Coming into contact with mould spores and chemicals can cause allergic reactions, so always wear gloves and a mask when dealing with mouldy surfaces.

damp walls

4. Fill Any Holes & Cracks

Part and parcel of painting any old, uneven internal walls includes filling any holes and cracks in the paint. 

If you aren’t skimming the walls or plastering, this part is key to ensure you have a smooth, flawless finish once painted. Fill any of the holes and cracks with filler on problem areas and leave to dry. 

You may also need to use a scraper at this point to remove the peeling paint, cracked parts and any old painting jobs that have drip marks, blotches and stains. 

damp walls 2

5. Sand The Walls

Once the filler has dried it’s time to sand back all of the area to get that smooth finish that is required for your first coat of paint. 

This is just as important as filling the holes. After doing so, clean the surrounding area of any dust and the walls so no debris fly onto the walls when painting. 

damp walls 3

6. Apply Stain Block

Before you start painting, in the first place apply stain blocker paint to the entire area that was previously affected by the damp. 

This will stop any visible stains from the previous damp rearing its ugly head through your lovely new paintwork. 

Stain block comes in a paint form or spray, it’s down to personal preference what you prefer but I find a sprint sprayer so much easier, and less hassle than paint.

Check Prices For Stain Block

7. Paint Your Walls

If you have followed all of the above steps, you’re ready to start painting! 

You should have provided a great line of defence against the damp, and the result should be flawless. When it comes to choosing the right type of paint, you may choose to use a mould-resistant paint or anti-condensation paint which is typically used in bathrooms or kitchens which tend to experience humid air.

If the walls develop paint bubbles, it is a sign that moisture is still present. This is incredibly annoying, but if it happens you do need to go back to the stage of letting the walls dry out for longer if the damp issue has already been solved. 

A top tip is to always use a paint sprayer or roller as it will always give you a much more flawless look than if you use a paintbrush.

damp walls 4

Damp walls can be an incredible, and unsightly annoyance, but as soon as the issue causing the damp has been identified, you can get your walls looking great, and damp free again.

f you’re looking for further help in solving the damp in your home, I’d really recommend heading over to the following post next which is all about damp in Victorian houses, practical tips and how we solved the issue in our terrace home.

Damp In Victorian Terrace Houses: How To Prevent & Cure It

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Nicole Sage

Nicole Sage is the founder of Sleek-chic Interiors and is a highly experienced interiors writer and skilled home renovator who has a passion for all things design. She has been featured as an authority at Pinterest, Ideal Home, Daily Mail and in countless other interviews. For 8 years, Nicole has written, observed key interior trends, renovated and undertaken interior short courses at the renown KLC school where she has gained her grounding interior design principles. With a keen eye for detail and a love of creativity, she shares her expertise on the latest interior trends, practical DIY tutorials, and styling inspiration to help others transform their homes into stunning spaces. With a commitment to delivering informative and engaging content, Nicole inspires and empowers readers to explore their own unique sense of style and create beautiful, personalised interiors. Contact her at for interiors advice, colour questions and any commentary.

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