Step by step to the horizontal basement seal


The basement is one of the most problematic weaknesses for many homeowners in terms of moisture and humidity. The same may apply to buildings built into a hillside. For many years, basement waterproofing was a real problem in the long term due to the lack of suitable materials, but now it is no longer. Here you will learn everything about professional and efficient basement waterproofing and receive detailed instructions.

The claims have changed dramatically

Cellar and dampness or moisture. For many people, these are concepts that somehow belong together. In fact, cellars have always been humid for centuries. In the past, however, these properties were exploited, since there were no really good sealing options. So the cellar was usually a storage room for numerous foods that could be wintered well in the damp, cold and dark cellar climate.

Basement waterproofing: only in consciousness for a few decades

Only in the course of the 20th century did the first useful seals emerge. So it took until the last third of the last century before really professional basement waterproofing could even establish. The basement seal was for a long time almost similar, regardless of the individual circumstances.

  • black cellar tub (sealed with tar or bitumen)
  • drainage
  • later then additionally a vertical seal (sheet steel or bitumen board after the first row of walls after the cellar base)

Only in recent years have come effective, durable sealing materials

Nevertheless, it must also be pointed out that it was quite a matter of luck until the 1990s, when all these Kellerabdichtungsmöglichkeiten were actually combined. But even if the combination exists - some of the materials, such as the waterproofing bitumen, have long been exposed unprotected to the water from the soil side and thus much shorter-lived than often hoped or assumed.

Construction of modern basement waterproofing

The modern basement seal not only takes into account the high level of knowledge, which is crucial for a cellar seal. In addition, numerous really high-quality products have come, which ensure decades of efficient cellar sealing. Thus, the professional seal construction is relatively complex (from the inside to the outside on the outer wall).

  • masonry
  • primer
  • special PIII plaster
  • Sealing on bitumen / plastic base
  • Perimeter insulation, optionally with horizontal drainage
  • dimpled sealing plates, optionally with horizontal drainage
  • Drainage (preferably circulating ring drainage)

Based on this structure, you can now make the basement seal.

Step-by-step instructions for horizontal cellar sealing

  • primer
  • suitable plaster (class P III)
  • tempered bitumen for basement exterior waterproofing
  • perimeter insulation
  • Knobs waterproof sheeting
  • Drainage pipe
  • possibly gravel for filling around the drainage
  • Mini excavators
  • shovel
  • wheelbarrow
  • pit props
  • Safety net against slipping earth
  • hammer
  • chisel
  • trowels
  • Electric drill with whisk
  • mortar bucket
  • Fillers for the bitumen
  • Saw (foxtail) for perimeter insulation

1. Preparatory work

First, of course, the pit must be dug along the basement wall to be sealed. Be sure not to dig deeper than 30 cm under the basement pedestal. Then you support the resulting, about 80 cm wide and often to the two-meter deep trench.

2nd age plaster

Old porous plaster, but also similar aged mortar in the stone joints you must remove or knock off. Then the basement wall is cleaned with a broom.

3. Priming

Now prime the masonry so that the plaster gets optimal adhesion. Follow the manufacturer's instructions accordingly.

4. plastering the basement walls

Now the basement walls are plastered completely new with the appropriate (P3) plaster. After plastering, it has to dry off, which can take up to 72 hours or more.

5. Apply the bitumen seal

When the plaster has dried, the bitumen seal comes. In soil with leachate, a 3 to 4 mm thick layer is sufficient. For pressing water, the layer should be up to 7 mm. However, the first wet applied layer should never be thicker than 3 mm. Then let it dry before applying the second coat to 7 mm. Between both bituminous layers you can insert an additional reinforcement (net).

6. Install the perimeter insulation

The perimeter insulation is usually glued with bitumen (as a bead or as a pile) on the back of the dried bitumen. The insulation is simplified by a kind of "tongue-and-groove" insulation boards in the form of a gradation, which engages from one plate to the other.

7. Lean on the dimpled sheet

Now the dimpled sheet with a clear supernatant upwards (may extend far into the later open wall area) is based on the Perimeterdämmung (with the pimples inside). Later, when filling, it is automatically pressed against the insulation and cut off at the top.

8. The drainage

Finally, then the drainage pipe is laid. At the highest point, it should not be above the basement pedestal. In addition, a percent slope should at least be present. The end of the drainage is optimally located in a seepage well or a corresponding seepage layer.

If you have excavated loamy soil, you should place the drainage in a gravel bed and fill it up to 30 cm above the drainage with gravel. Then the loose soil is filled. Again, you should not use loamy material before.

Tips & Tricks

Again and again, the injection seal is in discussion. You should replace the vertical seal, as this is only consuming (piece by piece) feasible. Injecting can be done from inside as well as outside. Bear in mind that the masonry must be absolutely dry. The effect is compared to a professional vertical cellar sealing at around 70, but a maximum of 80 percent. In the house journal you will find more specialist articles on cellar topics. So too to the different cellar designs like the white tub.


Video Board: How to Repair & Seal Expansion Joints in Concrete