Technical Booklet C Site Preparation and Resistance to Contaminants and Moisture·Page 36·6.32
Damp proof courses at obstructions and openings
Damp proof courses must be installed to direct moisture outward at lintels, under window and door sills, and around window and door reveals where these elements do not fully prevent water penetration.
Damp proof courses should be provided to direct moisture towards the outside –
(a) where the downward flow of moisture would be interrupted at an obstruction, e.g. at a lintel (see Diagram 6.3(b));
(b) where cill elements, including joints, do not form a complete barrier to the transfer of precipitation, e.g. under openings, windows and doors; and
(c) where reveal elements, including joints, do not form a complete barrier to the transfer of rain and snow, e.g. at openings, windows and doors.
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