Investigation method for damage reasons

There are several reasons for humidity damages. Water-leaking or non-existing external waterproofing lead to humidity ingress into the basement walls. Whenever the initial water load is changing, due for e.g.. to a non-functioning drainage system, this will lead temporarily to water pressure. 

The existing external basement water-proofing, the damp-proof barrier with injection resins in wall cross-section and the socket part of basement wall (above ground level) must be investigated relative to their type, condition, efficiency, and location. Also the damage appearance and the humidity content of the building parts must be inves-tigated.The degree of moisture penetration (ratio between moisture content and maximum water absorption)of masonry due to capillary uprising damp must be evaluated.

The degree of moisture penetration is essential for the choice of the injection resin and the penetration thickness of non-functioning damp-proof barrier.

Also damages due to defective pipes or high water/flood must be considered when taking renovation measures. Moisture on surface of building parts, caused by hygroscopic salts which are stored in the crystal structure, must be treated by applying an appropriate damp-proof render in accordance with the state of technique defined by WTA (Scientific and Technical Working Group for Building Conservation and Monument Preservation, Germany).

In case of condensation moisture all necessary thermal insulation measures must be taken. Not only the reasons for moisture damages must be evaluated, but also the built-up of walls must be considered. 

Which is most important during substrate check when renovating?

In the renovation area, the adhesion, the load-bearing capacity and the content of tar of the existing old waterproofing must be checked. For ex. if an "old black paint" is identified as tar, it must be completely removed by using suitable methods. The compatibility of bitumen old coatings and non-functioning polymer-modified bitumen thick coatings as base for the new building waterproofing must be examined. The check on a test area of the old waterproofing has proven to be a good method of assessment of drying and adhesion. Plasticizer migration and hence a loss of bonding will be hence excluded. Only under such conditions the requirements for a durable efficiency of the subsequent external waterproofing are given