Damp basement walls restrict the use of the rooms considerably and damage the building fabric. Permanent measures are worthwhile.
Due to changed circumstances such as rising groundwater levels or. structural changes in the immediate vicinity or errors, made when building the house, Pressurized water can penetrate through the basement walls. This error can hardly be permanently corrected from the inside. The best: Waterproofing of the walls from the outside. However, this measure is associated with a lot of earth movement. The basement of the house has to be dug up to the foundation to attach the waterproofing.
There are several options for sealing. The simplest is a bitumen sealant. However, the seal only becomes optimal with the additional attachment of a non-rotting dimpled membrane made of high-density polyethylene, which is absolutely tight and at the same time protects the black coating from damage. Due to the high nubs of the membrane, sufficient rear ventilation is guaranteed. So that no driving rain or water running down the house wall gets behind the knobbed membrane, the edge is covered by a profile. Is a further rise in the groundwater level or a large amount of surface water to be expected?, so should – especially in water-blocking soil layers – drainage to be laid immediately.
It depends on the timing
■ Wählen Sie zum Sanieren der Kellerwände die warme Frühlings- or daylight saving time, so that the exposed surfaces can dry well.
■ Gegen starken Schlagregen sollten Sie die Wände auf der Wetterseite provisorisch mit Folie abdecken, behind which air can circulate freely for drying.
The right attachment
First you need to determine, which of the basement walls you want to seal. This can be seen from within. Either by pure visual inspection, by feeling with the hand or with measuring devices. The area to be insulated on the outside wall should be at least one meter wider on both sides than the area on the inside, on which moisture has been detected. Have these spots increased over time?, you should work with an even wider overhang.
The workroom, which must be excavated, should be that wide, that one can work unhindered. The deeper you dig, the wider the working space and the flatter the slope of the trench must be. In any case, so flat, that no soil can slide down. Steep and deep embankments must be supported for safety.
After the wall is dry and clean, the dimpled membrane is rolled out on the wall, folded at the top for stabilization and approx. 10 cm fixed above the black paintwork with special large-head steel nails. The plastic profile comes on top of that. The trench is then backfilled with the excavated material, which, however, must not contain any stones or rubble.
Securing the construction site
■ The ditch must be secured against accidents. With a fixed railing or by covering with gratings or. a stable batten construction can be prevented, that someone falls in. Sufficiently illuminate the construction site and the surrounding area in the dark.