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require additional trays. The cavity tray should over lap the vertical DPC at the jamb. 4.3.2 Jambs To prevent the transmission of moisture, a continuous vertical damp proof course should be included behind jamb sections and this should extend at least 25mm into the cavity beyond the cavity closer. The DPC can be fixed to the window frame. Vertical DPC’s at openings should be located so as to overlap the horizontal DPC at cill level, whilst being overlapped by the horizontal DPC at the head. 4.3.3 Cills A horizontal damp proof course with stop ends should be provided in all jointed cills or sub-cills, for the full length and width of the cill bed. If the damp proof course is in contact with the inner leaf or cavity infill, the DPC should be turned up at the back and ends for the full depth of the cill. A cavity barrier/thermal barrier will be required to prevent cold bridging. Preformed cavity closers are available which provide both the damp proofing and thermal bridging requirements in one component.
walls, parapet walls and retaining walls exposed to the weather, should preferably be provided with a coping.” Copings should have a drip on the underside, positioned a minimum of 40 mm from the face of the wall. Where for aesthetic or other reasons a capping is used, consideration should be given to the durability of the construction beneath which may be exposed to wetting. A coping with drips positioned as indicated may still not shed rainwater clear of the wall surfaces beneath. A continuous DPC, supported over the cavity, will be required below a capping or coping detail to prevent the downward transfer of moisture into the wall. This DPC should be bedded on both sides so that it is sandwiched in the joint and projecting 5 mm beyond each face of the wall below. In parapet walls, a stepped cavity tray will be required which should fall a minimum of 150mm across the cavity. Weepholes, 75mm high are required at a maximum of 1m centres. Further reference should be made to BSI Standards Publication PD 6697: 2010 and BS 5642: Part 2:1983
Refer to BSI publication PD 6697 for full details. 4.3.4 Cappings and Copings BSI Standards Publication PD 6697: 2010 states that “Chimney terminals, freestanding
4.4 Position of Water Bars In cases of high exposure and to prevent water penetration through the joints in the cast stone, stainless steel water bars, bedded in polysulphide mastic, should be specified.
Position of DPC in parapet wall