Basement floor renovation made easy

Pärchen liegt entspannt auf einer Couch in einem ausgebauten Keller

Living space is rare and expensive. This is especially true in cities. In many houses, precious space slumbers unused in the basement. In contrast, a basement renovation allows enough space to fulfil the dream of a fitness room, a hobby room or a separate home office. The effort required for this work is less than many homeowners think.

We let out when a basement floor should be renovated and what is important when renovating.

When should a basement floor be renovated?

The number one reason for renovation is damp, cracked and uneven floors. Anyone who lives in an old building knows the problem of damp cellars. Until the 1970s, the concrete floor slab in the basement was not waterproofed. In many older houses, cellar floors, therefore, become damp after heavy rainfall, as soon as the groundwater level rises.

If water penetrates through leaky floors, musty smells and mould are frequent consequences. In addition to the health risk, permanent dampness is also a danger to the structure of the building. Therefore, the renovation of damp basement floors should always be carried out by experienced craftsmen.

Renovating a basement floor - this is how it's done

There are various methods to waterproof the basement floor retrospectively. Until now, this required several work steps and different materials. The self-levelling and watertight floor compound weber.tec 932 simplifies the process. It saves time by combining several work steps.

To save time

weber.tec 932 combines all the requirements for quick and easy floor renovation in one product: The skilled craftsman can waterproof and level in just one work step. The 2-in-1 solution quickly and easily protects the floor against rising damp from outside and at the same time levels out uneven and inclined floors. This allows the craftsman to waterproof the basement floor in a single day. The material also dries quickly. After three to five hours, the new poured cellar floor can be walked on. After seven days it is open to full load. This is how cellar rooms become newly habitable within one week.

Keep a lot of headroom

The mineral watertight floor compound is not demanding as far as the substrate is concerned. It is suitable for almost all substrates, including old screeds, tamped concrete and well-bonded brick floors. Rising damp is already stopped by a layer thickness of five millimeters of the levelling and watertight floor compound. Due to this low build-up height, residents hardly lose any headroom. This is important because most cellars are not particularly high.

The conditions

The first step is to carefully inspect the floor. If there is moisture damage, the cause should first be clarified For the specialist to be able to successfully waterproof and renovate the basement floor, the floor must be load-bearing, frost-free and clean. Adhesion-impairing particles and substances are removed, and cracks in the substrate are filled with epoxy resin. Only when the floor is dry can the application of the watertight floor compound begin.

The single steps

At first, the whole surface is primed, so that the subsequent layer has a good key with the substrate. In the case of bricks, the primer should be applied several times. Upon its drying, the specialist waterproofs the transition area between the floor and wall with a reactive waterproofing coating. Next, he glues a foam strip around all wall/floor connections that "stops" the compound from flowing there. Afterwards, he measures the slope to calculate the layer thickness, so that he knows how much material he needs. For brick floors, the layer of the product must be at least 15 millimeters. The next step is the mixing of the product with the specified amount of water until a homogeneous, easy-flow consistency is achieved. Then he pours the mixed material uniformly and without delay, starting from one side. After application and after reaching the required layer thickness, the last step is the smoothing of the fresh layer with a flat rake. For thicker coats, it is recommended to de-aerate the layer with a wobbling bar. After that, it's just a matter of waiting. The floor can be walked on after five hours at the latest. Now the waterproof and even surface can either be covered with a top layer, such as tiles, but can also be used directly without any further covering as a wear layer. It is suitable for light mechanical loads, such as occur in typical domestic uses.


In some regions additional protection against radon gas should be planned before using basement rooms.

Radon is a natural radioactive gas that is formed in the ground by the decay of uranium. When exposed to air, the colourless and odourless radon decays in a short time. However, it penetrates buildings through unprotected foundations or basement walls. If radon accumulates in higher concentrations (over 300 becquerels per cubic meter as an annual average) in closed rooms, the risk of lung cancer increases significantly.

Some products used to protect against rising damp also protect against radon exposure. If there is exposure to radon, the whole surface is waterproofed with the reactive waterproofing coating weber.tec Superflex D 24 in a dry layer thickness of four millimeters before applying weber.tec 932. After thorough drying, weber.tec 932 is applied in a minimum layer thickness of ten millimeters without further priming.