How to paint on a wet wall?


Moisture is a common problem in many homes. But how do you repaint the walls when they are damp? Do not panic. Here are some solutions that can help you.

Identify and regulate the humidity of the walls

Moisture in the 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 the infiltration which causes the introduction of water into the cracks in the wall. Moisture can also come from the ground and cause what is called capillary rise. A final cause is the poor insulation of the roof. This defect promotes humidity at the 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. For example, he could provide 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 realization of a water-repellent treatment.

Painting a healthy wall

Once the source of the humidity has been resolved, it is necessary to wait a certain period of time before painting, while the support dries in depth. 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 some for home use in the trade. Once the wall is dry, it’s time to start painting.

Prepare the support by cleaning any traces of saltpetre and mold. Scrape them with a flat knife and then clean with bleach mixed with water. Wait about 30 minutes before rinsing well with hot 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 painting. The work ends with the application of the undercoat and paint.

Paint a wall that stays wet

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

We recommend them especially in damp rooms such as the kitchen or the bathroom. In the event that the humidity comes from the air and is due to condensation, it is still 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.