Old buildings score high when it comes to nostalgia. However, when it comes to modern insulation standards, they lag far behind. Unfortunately, this often also applies to a sensible moisture barrier. And so the water slowly creeps up the cellar walls, causing mold and unhealthy indoor air. But wait! Can’t you do anything here? Of course, that is possible! And we even explain exactly what to do. We let experts show us how to renovate damp walls!

Always trouble with damp walls.

Old buildings are both a blessing and a curse. They indeed offer a noble appearance and a lifestyle that is unparalleled today. However, they mostly lack modern building standards. That means a lot of work when renovating. It becomes particularly challenging when an inadequate seal has already caused moisture damage.

Anyone who has ever stood in front of a basement wall that has been eaten away by the mold knows the problem. We don’t want to dare to experiment either, and in a particularly delicate case, we get professional help by our side. The aim is to renovate the damp walls in such a way that we save ourselves subsequent trouble.

Wanted, found: We learned from the experts at Buschek how to professionally renovate damp walls and how important it is to choose the right damp-proof plaster. And we are now passing this knowledge on to you!

Determine moisture penetration

To begin with, an overview of the size of the problem must first be gained. This is the only way to take the right measures than to renovate the damp walls successfully. A rough assessment can be obtained using digital pre-test devices.

The digital helpers only measure up to 20 cm deep into the building fabric. However, this is entirely sufficient to scan the walls for moisture systematically. In our case, it quickly becomes clear that the moisture must have risen to just below the ceiling. But how damp are the walls?

One thing quickly becomes clear: the problem is so serious that even the inner walls bordering the outer walls have absorbed moisture. Only a more detailed analysis can bring final clarity here. So drill samples are taken at different points on the wall. The drilling dust from the holes is collected, packed airtight, and then sent to the laboratory.

Once there, moisture measurement is carried out with the help of the drilling dust. The exact degree of moisture penetration for each drill sample is determined using a gravimetric method. This then results in a pattern for the entire wall.

The result: in the base area of ​​the wall, the degree of moisture penetration is already 100%. Just below the ceiling, it is at least 80%. This means that the wall is almost entirely damp.

Create a horizontal seal

In such a severe case, the first step is to add a horizontal seal to the wall. Otherwise, it would be a wasted effort trying to renovate the damp walls. Because first, the cause of the problem has to be eliminated.

The horizontal barrier should be done via a cream injection. For this purpose, the plaster is completely knocked off in the base area of ​​the wall. In the underlying 80 cm thick quarry stone wall, 75 cm deep blind holes are then made at a distance of 10 cm. The holes have a diameter of 16 mm.

The drill holes are blown out with compressed air in preparation and then flooded. Pre-flooding is a process in which pH regulators are injected into the wall. This allows the pH value in the wall to be adjusted so that the function of the injection cream is guaranteed at all times.

Everything is now ready to fill the drill holes with Gesan injection cream. A so-called injection pump is used for this. With their help, the cream injection is carried out quickly, and the holes can be filled. In the following four weeks, the horizontal barrier will set, and the wall above it will slowly dry.

Plaster the wall again

Subsequent horizontal sealing contributes significantly to successful wall drainage. But the main part of the work is still to be done. Since the wall was attacked at full height, the entire plaster must now also be removed. In less severe cases, it would be possible to limit the renovation to an area up to 30 cm above the soaked areas.

And something else is very important for the success of the measures: the right plaster! Open-pored damp wall plaster is needed, which allows the wall to continue to release moisture. Otherwise, the water would climb higher and kick out of the wall further up.

For the following work, we used the Buschek damp wall plaster. Thanks to its open-pored structure, this can be applied to the wall with a residual moisture level of 50%. First, a pre-spray with high water content is made from it. This is thrown against the wall with a trowel, which requires some practice.

After drying, the thicker rough plaster follows. This is also thrown against the wall but then balanced and smoothed. The fine plaster can then be applied to the surface prepared in this way. This must also be open-pored so that the result is correct.

Note: If you are more interested in how damp walls can be renovated, don’t miss our instructions for plastering damp walls. In it, we describe the procedure again step by step!

What should be considered in the end

Moisture in the walls is a massive problem and should not be underestimated. But as we now know, thanks to the experts at Buschek, this annoyance can also be brought under control. The right measures must be taken.

However, the eye for details must be retained even after plastering. The work would have been in vain if the walls were then painted with any color. The color also needs an open-pored structure. Otherwise, the wall would be sealed again in the end.

Tip: It is advisable to stick with the wall paint in the same system from which the plaster comes. So you can be sure that all components are coordinated with each other. And you have one less worry when you have to renovate damp walls!

Sanierungsbedürftiger Altbau
Sichtbar feuchte Wand
Wärmebrücken mit Schimmelbefall
Durchfeuchtung grob bestimmen