Technical Booklet C Site Preparation and Resistance to Contaminants and Moisture·Page 35·6.31
Joints at doors and windows in external walls
Joints between walls and door or window frames must prevent precipitation entering the building and must not be damaged by precipitation or allow water to reach areas that could be damaged.
The joint between walls and door or window frames should – (a) resist the penetration of precipitation to the inside of the building; and (b) not be damaged by precipitation and not permit precipitation to reach any part of the building which would be damaged by it.
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