How to paint on a wet wall ?

Dampness is a common problem in many homes. But how then to repaint the walls while they are damp? Do not panic. Here are some solutions that can help you.

Identify and adjust wall dampness

Damp walls can have several causes. Condensation is the most common. It is mainly due to poor ventilation in the house and occurs in the kitchen, bathroom or laundry rooms. Sometimes it leads to the appearance of mold.

Another possible cause is infiltration which causes water to enter cracks in the wall. Moisture can also come from the ground and cause what is called capillary rise. A final cause is poor roof insulation. This defect promotes humidity at roof level.

Note that it is not always easy to detect the origins of the problem. Hence the importance of calling on a real specialist who will carry out a humidity diagnosis and guide you on the appropriate treatment to undertake. He could, for example, propose drainage that will facilitate the evacuation of water in the foundations, the installation of a better ventilation system, the installation of a waterproof membrane or the implementation of a water-repellent treatment.

Painting a healthy wall

Once the origin of the humidity has been resolved, it is necessary to wait a certain period of time before painting, until the support dries thoroughly. To be sure, just touch the wall. However, the ideal is to use a humidity tester. It is a professional tool, but it is possible to find one for home use in the trade. Once the wall is dry, it’s time to start painting.

Prepare the surface by cleaning any traces of saltpetre and mould. Scrape them with a flat knife then clean with bleach mixed with water. Wait about thirty minutes before rinsing well with warm water. After drying, fill any holes or cracks with a filler and finish with the application of a smoothing filler which will give a smoother appearance to the support and thus facilitate the application of paint. The work ends with the application of the undercoat and the paint.

Painting a wall that remains damp

If despite all your efforts, the wall continues to remain damp. All is not lost. It is still possible to repaint using, for example, anti-humidity paint which forms a barrier against humidity. But beware, the manufacturers say it themselves, complications can arise with this type of paint if the humidity is too abundant.

They are especially recommended in humid rooms such as the kitchen or the bathroom. In the case where the humidity comes from the air and is due to condensation, it is possible to consider the use of a water-repellent paint. It has the particularity of being waterproof and self-cleaning. It will also be recommended in damp rooms or even floors. The last option is microporous paint, but it is more effective on woodwork.

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