3. Existing waterproofing

3.1 Study for the conservation of the old waterproofing

Waterproofing can only be retained in compliance with current regulations, i.e. only if the required diagnosis is positive. First of all, it is necessary to define the new function assigned to the retained waterproofing.

This can be :

• support for new thermal insulation, the thickness of which must be calculated. It can be used as a vapour barrier, except in the case of synthetic membranes such as PVC, pasty plaster or volcanic cement. Note that DTU 43 – 5 describes some exceptions to this rule:

• support of new thermal insulation on a metal support of ribbed steel sheets (TAN), conservation possible, even if a vapour barrier...