Painting a wet wall requires a different approach than painting a dry wall. The key is to address the moisture problem before painting to prevent peeling, bubbling, and mold growth. Simply painting over a wet wall will likely lead to failure.
Assessing the Situation
First, determine the source of the moisture. Is it a leak? Condensation? Rising damp? Addressing the root cause is crucial before any painting takes place. If the source isn't fixed, the paint will fail regardless of the type used.
Preparing the Wet Wall
Before painting, the wall must be thoroughly dried. This may involve several steps:
- Identify and repair the source of moisture: This might involve fixing leaky pipes, improving ventilation, or addressing rising damp.
- Remove any mold or mildew: Use a suitable cleaning solution to eliminate mold growth.
- Allow the wall to dry completely: This could take days or even weeks, depending on the extent of moisture. Use a moisture meter to ensure the wall is fully dry.
- Repair any damage: Once dry, repair any cracks or holes in the wall using appropriate filler. Sand smooth once dry.
- Apply a waterproof sealant: This creates a barrier against future moisture.
Choosing the Right Paint
Even after drying, it's essential to use a paint formulated for damp conditions. Several sources suggest the following:
- Breathable, water-based paints: These allow moisture to escape, preventing trapping and future issues. Contract emulsion is often recommended. (mybuilder.com)
- Acrylic paints: These are less susceptible to blistering, flaking, or cracking in humid environments. (Island Paints)
- Using a primer: A primer specifically designed for wet walls will provide a better base for the paint and help to prevent moisture damage. DRYLOK® Wet Wall Bonding Primer is one example of a product designed for this purpose. (drylok.com)
Painting the Wall
Once the wall is prepared and completely dry, paint using the chosen method. Use high-quality brushes and rollers for optimal results. If you are concerned about a remaining moisture issue, it is best to use thin coats to minimize any trapping of moisture in the wall.
Addressing Other Scenarios
Some sources mention issues like surfactant leaching, which can cause paint to look wet even after drying. In these cases, addressing the underlying cause, such as high-moisture environments in the room are necessary. For example, reactivation of surfactant within paint due to steam in a shower room may require different strategies such as increasing ventilation or using a more appropriate paint suited for such environments.
