ADPC property Care

Brief overview of

Structural Water Proofing

(which includes Tanking)

Remedial structural water proofing in older/existing properties is normally carried out from the inner wall surface using (Type C) Cavity Drain Membrane as the older wall/floor masonry may be in a weakened condition as CDM will not put additional load on the floor and wall structure, sometimes a combination of type A & C may be used. The cavity drain membrane manages the failure of the buildings ability to resist ground water penetration.

In the Edinburgh area, the Type C system is commonly used to control the water percolating down through the permeable ground above an under pavement cellar. The base of Edinburgh new town area cellars is normally well-drained and no water table issue due to the design of the building, but a drainage point may be installed at the cellar door to control any excess water via the existing gully drainage system.

New build structures have a different set of waterproofing problems compared to existing and require a desk study followed by a site inspection to select materials and create a suitable specification.  Which may be a combination of Type A and B waterproofing system, this is applied to the new structure externally (Type A) or as part of the construction (Type B) both may require a suitable maintainable land drain installed to prevent water building up on the outside and finding a defect.  By combining these, you may create a Tanked construction.


Type A system relies on a coating/membrane being applied to the wall/floor to make the  structure resistant to the passage of ground water .  A manageable land drain can be installed to prevent water finding defect in an external coating or membrane.

Type B:  this is the best form  as the  (normally  water proof concrete) wall/floor construction  is resistant to ground water penetration.

Type C:  the is formed out of a dimpled plastic membrane which manages the water entering the building. this is often used for repairing an area (this is not a tanking system).  It can be combined with Type A or B to make them more repairable.