Plastering walls after moisture? What to consider?

It is possible to plaster a wall if you find moisture is present, but not always. It is important to know exactly where the moisture is coming from before you start plastering. Therefore, the answer mainly depends on whether it concerns a new build or a renovation. In each of these situations, you tackle a moisture problem differently. With renovation, you often don’t know how the foundation and walls are constructed, while that is the case with a new-build home.

Whatever type of home you have and whatever type of plaster you want, the substrate is always the determining factor for the beautiful, aesthetic finish of your walls. Therefore, it is good to examine the walls before you start plastering or to have a moisture diagnosis carried out immediately. This often saves a lot of costs in the long term.

Before plastering: check the wall

The substrate is as important for the end result as the quality of the plasterwork. The porosity of the bricks, for example, is decisive for the choice of plaster and any pre-treatment.

There is a small control test that gives you a first indication of the humidity in the walls. Rub a wet brush over the wall and see how long the moisture remains on the wall. With a healthy wall, the moisture starts to dry after five minutes. However, does the moisture remain on the walls and does it dry very slowly? Then the wall is very susceptible to moisture. If in doubt, it is recommended to request a moisture diagnosis.

Only a moisture expert performs extremely accurate measurements, so you know the exact humidity level of your walls. At the same time, you also know what the best materials are to plaster your wall. Here too, the age of your home plays an important role. The brickwork of a new-build home still feels very damp for the first few months, because the walls still have to dry out.

You can only start plastering when these are completely dry. The drying time depends on the porosity of the construction materials, the possible presence of heating in the home and the ambient temperature. A home dries more easily in the summer than in the winter. It usually takes an average of three to six months for the walls to dry out completely.

It is important to have a moisture diagnosis carried out as soon as you notice that the walls are not completely dry after six months. With a professional moisture diagnosis, you know exactly what is going on and what you should do to tackle the problem. If it turns out that the moisture problem is mainly due to the poor condition of the exterior walls, your specialist will suggest other techniques to tackle the water from the outside of the home, for example with a protective facade cleaning. At Aquavent, we always work thoroughly to know the precise cause and we tackle your home preventively.

Moisture problem? Then you should not plaster

Do you find moisture and have you not yet carried out any work? Then there is a good chance that you are dealing with a moisture problem. In that case, it is not possible to plaster your wall. If there is rising or penetrating damp, the plasterwork can never dry, which would cause it to crumble again in the long term. A waste of effort. Therefore, it is worth having the condition of your interior wall thoroughly checked by a moisture specialist first. The good news is that you always have a solution to dry your walls, after which you can undoubtedly get started with your plasterwork.

It is important to know that a moisture treatment is not always sufficient to dry your walls. This is the case, for example, when there are cold bridges that lead to poor insulation of the home. This may be the case when you notice condensation on your windows. With condensation, there is no ‘real’ moisture problem yet, but then you know that you should first renovate the walls before finishing them with plaster. It is then often necessary to renew the windows.

In new builds, there is a chance that the walls will remain damp for longer without there being a moisture problem. This is because the walls are then very well insulated, but there is, for example, insufficient ventilation to remove the moisture. And then there is often too little heat present to allow the moisture to evaporate. In a new-build home, ventilation and heating are therefore necessary to ensure that all walls dry out. The same problem often occurs in a thoroughly renovated home, for example after the installation of cavity wall insulation.

Are there water droplets on the windows or walls? Or do you have a clammy feeling indoors? Then it is best to ensure that the heating inside remains at the same temperature and that mechanical ventilation is present. With this ventilation system, you are always sure that there is a healthy indoor climate and that you prevent moisture problems in time. Mechanical ventilation is mandatory in new builds or in newly renovated homes.

Tips to make plaster dry faster

Plaster contains a lot of water, which means it can take a while before a new or renovated house can be inhabited. The plaster layers must first be dry. It is important that the indoor temperature remains constant during the drying process, so that the plaster does not show cracks or fissures. Therefore, it is good to heat and, above all, ventilate the room at the same time.

Since you can ventilate more easily during the summer, this is also the ideal time to have the plastering carried out. Are you having the plastering done in the winter? Then it is important to install a heating device so that the indoor temperature remains above 15° C and also to ventilate sufficiently.

The substrate also influences the drying time. Building materials with a strong absorption capacity usually absorb water faster. At the same time, it is important that the substrate also dries out completely. In order to protect the substrate against the excess moisture from the plaster, it is often necessary to use a pre-treatment. As a specialist in the treatment of moisture problems, we therefore also advise you on the primers or primers that you may need to avoid moisture problems in the long term.