I have scoured this forum for answers to this query but failing to find ‘chapter and verse’ I thought I would ask my specific questions in the hope that some of the admirable expert posters on here might set me straight. I would be very grateful.
The architect for a detached newbuild is telling me that although the DPC in the outer leaf of the cavity walls is generally less than half the normal 150mm height above adjacent ground level, that this is OK because the walls include a cavity tray at DPC height. (The walls are brick and block, engineering brick below DPC, facing bricks above.)
I am being told that the cavity tray adds ‘four more courses’ of protection for the inner leaf.
Is that the case? Is that an established/recognised way to make lower than regulation height DPCs acceptable?
The building had final sign off from building control though it isn’t clear whether some of the adjacent landscaping was in place when it was signed off. One intermediate site visit by the BC inspector records his discussing the need for cavity trays ‘where the land is higher’.
The DPC along the rear wall of the house is scarcely 10mm above finished ground level but has an ACO type drain immediately in front of the wall along its whole length, which includes patio doors with an almost level threshold.
There is complication though. Land immediately adjacent to the house, but not belonging to the house, was landscaped by the same builder after BC final sign off and the finished surface is, by my estimate, approximately 4 brick courses higher than the external DPC which is now effectively underground along some of that wall as a result. Comments on that and how it might be resolved, assuming it is an issue, would be very welcome.
And finally, am I right in thinking that a cavity tray installed at DPC level would have to have weep holes to be effective?
I am aware of the 'rain splash up' issue with a low DPC but imagine that appropriate applications of Stormdry above the DPC could resolve that - though obviously not where it is underground!
Any advice would be gratefully received!
The architect for a detached newbuild is telling me that although the DPC in the outer leaf of the cavity walls is generally less than half the normal 150mm height above adjacent ground level, that this is OK because the walls include a cavity tray at DPC height. (The walls are brick and block, engineering brick below DPC, facing bricks above.)
I am being told that the cavity tray adds ‘four more courses’ of protection for the inner leaf.
Is that the case? Is that an established/recognised way to make lower than regulation height DPCs acceptable?
The building had final sign off from building control though it isn’t clear whether some of the adjacent landscaping was in place when it was signed off. One intermediate site visit by the BC inspector records his discussing the need for cavity trays ‘where the land is higher’.
The DPC along the rear wall of the house is scarcely 10mm above finished ground level but has an ACO type drain immediately in front of the wall along its whole length, which includes patio doors with an almost level threshold.
There is complication though. Land immediately adjacent to the house, but not belonging to the house, was landscaped by the same builder after BC final sign off and the finished surface is, by my estimate, approximately 4 brick courses higher than the external DPC which is now effectively underground along some of that wall as a result. Comments on that and how it might be resolved, assuming it is an issue, would be very welcome.
And finally, am I right in thinking that a cavity tray installed at DPC level would have to have weep holes to be effective?
I am aware of the 'rain splash up' issue with a low DPC but imagine that appropriate applications of Stormdry above the DPC could resolve that - though obviously not where it is underground!
Any advice would be gratefully received!
