Cellar floor seal against moisture


If the basement floor is damp, you can heat as much as you want, in the rooms you can not store anything and certainly do not live. Therefore, the basement floor should be sealed as soon as possible.

Eliminate causes of moisture

Of course, before making any waterproofing on the basement floor, the causes of the moisture must be determined and eliminated. Especially if you later want to live in the rooms too.

Clay soil or concrete slab

In older houses, it may be that in the basement still no bottom plate is present, but only milled clay forms the floor. Nevertheless, the causes of moisture must also be determined here.

Seal the basement floor step by step

Depending on the scope of the measures you will not need all listed materials and tools. Here we want to show the sealing of a clay soil in the cellar.

  • Gravel / sand
  • lean concrete
  • foil
  • concrete
  • Insulation / insulation
  • Bitumen / liquid plastic
  • leveling screed
  • shovel
  • spatula
  • trowel
  • Mason Balje
  • bucket
  • spirit level
  • mixer
  • ruler
  • Masonry stirrer on drill

1. Lift old ground

Also think about the later room height, because through the seal and the isolated floor, finally, a lot of height is lost. But you should not dig deeper than the old foundations of the walls are enough.

2. Insert functional layer

A layer of about five centimeters of gravel or lean concrete forms the first layer of the new cellar floor. Then a layer of concrete is poured. This should be at least three inches thick.

3. Apply plastic film

After sufficient drying of the lower layers, a vapor barrier made of plastic is now applied. There are different solutions for this.

Depending on whether you are applying a liquid plastic or a foil, do not forget to pull it up the edge sufficiently so that the wall seal works later.

4. insulation

On the plastic layer, the thermal insulation is applied. As a rule, polystyrene plates are used for this purpose.

5th screed

Many recommend another plastic film on the insulation before the screed is applied. This falls under the category of taste. It is safer, of course, to shut off the moisture again.

Then the screed can be applied. Here you have to work quickly, so as not to have any bumps in the ground later. When the screed has dried, this floor can be covered with laminate, PVC or carpet as normal.

Tips & Tricks

For a cellar in which you do not want to live, of course you do not need to put any flooring on the screed. But PVC is more comfortable than bare concrete and can also ward off moisture.


Video Board: TEC product: LiquiDam EZ moisture vapor barrier