Basement Tanking System – Lateral Penetrating Dampness

This is an older style property, located on sloping ground near St. Albans Abbey, an area that frequently has drainage problems with moderate to heavy rainfall. Garratt’s Damp and Timber has a long history of remedial works relating to lateral penetrating dampness in this town.

The small terraced house suffered from regular water ingress to the basement. Garratt’s undertook the commission to install a tanking system with a sump and pump to restore the area to habitable condition. Prior to specification, it is important to assess the usage of a basement; we learned that the basement was intended for use as a music room.

The procedure of returning the room to domestic use involved many steps to ensure a watertight, damp free environment. The photos in this case study were taken by our surveyor during various stages of the project, showing the full process of tanking a basement area.

• Step 1 – Preparation of walls. Removal of unsound material from walls such as unbounded render, and removal of organic materials present in the substrate which may deteriorate in the presence of dampness, including timber and gypsum plaster. Exceptionally uneven walls should be rendered to ensure a reasonably flat surface prior to applying membrane. In this example, most preparatory tasks were unnecessary as the walls were of sound and uncontaminated painted brickwork
• Step 2 – Preparation of stairs. Re-finishing basement footsteps using a cementitious tanking system such as SIKA 1 or Vandex BB Multicoating Thoroseal
• Step 3 - Lining of all walls with a membrane and stud fixing to the full length of wall with a short skirt to floor area, depending on the floor finish
• Step 4 – Sealing all joints in the membrane with an appropriate proprietary material like butyl tape
• Step 5 – Battening membraned walls in order to provide a solid fixing point for plasterboard
• Step 6 – Dry-lining of all membraned walls with plasterboard and fitting of angle beads prior to applying the finish plaster

We hope you have enjoyed reading about this case study. If you have any feedback, please drop us a line on info@dampproofing-london.co.uk.