A damp cellar is treated from outside, from inside, or through the floor. Not at random.

What you see

Walls that sweat or powder, a puddle that returns after every heavy rain, a cellar smell rising into the hallway, cardboard boxes going mouldy, render coming off in sheets. Sometimes only a cold, dark band low on the wall while the top stays dry.

Each sign points to a cause. The puddle after rain: water entering through the wall or a light well. Constant sweating: the water table or saturated soil pushing through the brick. The cold band at the bottom: damp rising from the cellar floor.

Where it comes from

The buried wall. On the other side there is wet soil, and nothing in between. The brick drinks.

The water table. In the Senne and Maelbeek valleys, in Anderlecht, Forest, Molenbeek and lower Ixelles, groundwater is close and rises in winter. The cellar ends up below water level a few weeks a year.

The cellar floor. Beaten earth or a slab laid without a membrane: moisture rises through the floor and the foot of the walls.

The drain, where there is one. Often blocked after forty years. The water it was meant to carry away stays against the wall.

Summer. Warm, humid air entering a cold cellar condenses on the walls. Airing a cellar in July makes it wet.

What we do

From outside, when the wall can be reached: dig the soil away, lay waterproofing and a drain, backfill with draining material. This treats the cause. It requires room to dig.

From inside, tanking: a multi-layer waterproof coating that holds back water pushing in from the soil. It makes the cellar dry without touching the garden or the pavement. It needs serious preparation of the wall, and ventilation afterwards.

Through the floor: a slab with a membrane, or a surface treatment depending on the intended use.

Ventilation, in every case: a sealed cellar with no air becomes a condensation box.

What it costs

On the Belgian market tanking is priced most often between 150 and 300 € per m² of treated wall, a drain between 80 and 150 € per metre, and external waterproofing depends on the depth to dig and the access. Indicative ranges, not our rates: yours is put in writing after the visit. 6 % VAT if the home is over ten years old.