Building Construction Handbook, Eighth Edition

Function † the primary function of any damp-proof course (dpc) or

damp-proof membrane (dpm) is to provide an impermeable barrier

to the passage of moisture. The three basic ways in which damp-

proof courses are used is to:-

1. Resist moisture penetration from below (rising damp).

2. Resist moisture penetration from above.


3. Resist moisture penetration from horizontal entry.

Typical examples ~

external

wall

passage

of moisture dpm lapped

with dpc

weep

holes at

900 c/c

ground

floor

dpc's

cavity

insulation

galvanised

steel lintel

with

insulated

fill and

a polyester

coating

as integral

dpc

lintel

extends

150 mm min.

as end

bearing

rain

PENETRATION FROM BELOW

(Ground Floor/External Wall)

PENETRATION FROM ABOVE

(Window/Door Head)

(^150) min.
internal reveal
see also page 350
vertical dpc
traditional
uninsulated
cavity
HORIZONTAL ENTRY (Window/Door Jamb)
cavity closer/dpc
external wall mastic
rain seal rain
See also: BSs 743, 8102 and 8215.
Damp-proof Courses and Membranes