Deflecting penetrating water to the outside of external walls

External solid and cavity walls should be constructed to deflect penetrating water towards the outer face of the wall such as in the following locations – (a) below copings at the top of walls (see Diagram 6.3(a)), unless the coping and joints will form a complete barrier to moisture; (b) where the downward flow of water will be interrupted by a cavity bridge, such as at some types of lintel (see Diagram 6.3(b)); (c) under openings, unless there is a cill and the cill and its joints will form a complete barrier; and (d) at abutments between walls and roofs. Damp proof courses, cavity trays and closers should be provided and installed to ensure that water drains outwards.