Planning of internal basement renovation works

Which standards are existing?

The leaflet 4 - 6 of WTA (Scientific and Technical Working Group for Building Conservation and Monument Preservation, Germany) Subsequent waterproofing of earth-contacting building structures" provides helpful information for the evaluation of damages, the concept of waterproofing and the description of subsequent waterproofing works. Combinable waterproofing concepts are regulated in this leaflet according to the type of water load and the use of basement rooms.


If the external waterproofing is not justifiable from a technical or economical point of view, as for example in the case of a super-structure with a garage or a neighbouring extension, the measures for internal water-proofing which are described in these regulations, have proven to be common and proven in practice for many years. These regulations therefore are considered as generally recognised technical rules.

The fundamental difference with an external waterproofing is that the masonry in the core is still soaked through and contaminated with all pollutants present in the soil. In general, basement masonry consists of water-resistant building materials.

The constant moisture penetration in the external basement walls usually does not lead to stability problems. It is, however, absolutely necessary to bring the mineral internal waterproofing up to the level of a horizontal damp-proof barrier in the masonry or to install a subsequent cross-sectional waterproofing. Protective layers can be "wear" layers, such as internal thermal insulation or damp-proof renders as buffers for condensation can be applied after complete drying of the mineral internal waterproofing.

What is important to consider when planning basement renovations?

Subsequent mineral interior waterproofings fulfil the requirement for the waterproofing function in the same way like professional and accurately executed external waterproofings.