Book Description

The function of a damp proof course (d.p.c.) is to prevent or to reduce as much as necessary the passage of moisture from parts of walls or floors that cannot be kept dry to parts that must be kept dry. Direct rain shedding components, such as roof coverings and flashings, and tanking to basements are not discussed in this Digest and are mentioned only in so far as they may relate to damp proof courses. Damp proof membranes in solid ground floors are dealt with fully in Digest no. 1, but the main features are repeated here.

Besides the ability of the d.p.c. to resist the passage of moisture and the correctness of its position in the structure, there are other points to be considered if the d.p.c. is to be fully effective at all times. These include

(1) the direction of the movement of moisture that is to be resisted,

(2) the mechanical properties that may be needed to enable the material to withstand relative movement or deformation under load without impairing its efficacy, or to enable it to be laid properly,

(3) the effective life of the material and

(4) the preparation of the base on which the d.p.c. is to be laid.

These points are dealt with first in this Digest and are followed by notes on the various d.p.c. materials in which their properties are related to these requirements; finally examples are given of damp-proof courses in relation to the part of the building to be protected and to adjoining damp-proof membranes, weatherproof coverings and flashings.

Replaced by Digest 77 (2nd series).