How to make bitumen

Apply bitumen paint - this is how it's done

Bitumen paint on the outer cellar wall

If the outside of a cellar wall is only exposed to soil moisture and, if necessary, a little seepage water, you can usually get by with a bitumen insulation layer if the layer thickness is large enough (3 top coats).

If the outer cellar wall comes into contact with more water (strong seepage water, running water), on the other hand, you need at least a thick bitumen coating and some additional measures.

In the case of pressing water, further and additional protective measures may have to be taken - in such a case, you should definitely leave the planning and sealing to a specialist.

Construction of a bitumen coating on the cellar wall

Painting alone is not enough. In addition, a few more layers are necessary:

  • Sealing slurry
  • Primer
  • Top coat (actual insulating bitumen paint)
  • 2 more top coats
  • Cover (possibly barrier membrane, plastic film)

Sealing slurry

Sealing slurries are a mixture of cement, various minerals and aggregates as well as plastic. This cement-plastic mixture is an excellent seal for masonry, which is also simple and very inexpensive.

Sealing slurries can be used on concrete, cement plaster and fully jointed masonry. They are generally painted in three layers on top of each other. If a substrate is very absorbent, the wall must be moistened a little before painting the sealing slurry. The application is very easy: stir in the bucket and brush on the wall with the brush.


We have written our own article about priming bitumen paints. You can find it here.

Blocking tracks

Barrier sheets are sheets of polymer bitumen that serve to protect the underlying coating. Alternatively, special plastic films can also be used for this purpose. Barriers are the classic variant, which also works very well.

The higher protection serves to keep the bitumen layer from decomposing too early. Bitumen seals against water, but is also attacked by it over long periods of time. An additional barrier strip prevents this to a large extent and thus ensures a longer service life for the coating.

In the case of basement walls, covings with a radius of 5 - 6 cm must also be worked into the floor and wall connections. Bitumen coatings can also be applied indoors.

Author: Johanna Bauer Home »Building» Building Materials »Bitumen