Protection and Wet Deflection - Best Practice
Avoiding exterior skin deficiency
There are situations where it is preferable to approach damp control measures from a different direction. This is particularly relevant where partial or full fill insulation terminates horizontally (at plate level) across a gable wall. It also applies where any cavity impingement occurs, where the thickness of the exterior skin changes partway up the height of the wall or traditionally shaped cavity stops and barriers horizontally close the cavity.
The Type CD Cavity Dropcloak is manufactured by Cavity Trays of Yeovil provides an easy compliant approach accompanied with several benefits.
The Type CD Dropcloak is a pre-shaped DPC cavitray moulded from Petheleyne. It is supported in position by being partially built into the inner skin only. It functions as a protective cloaking section that drops downwardly and forwardly in the cavity, guarding against wet transference via the upper surface of any insulation, cavity barrier or impinging masonry under it.
Because the Type CD does not build into the outer skin, the outer skin is not weakened by DPC presence through it. (picture) Accordingly use of the Type CD avoids the commonplace accompanying cracking as a result of slip-plane movement that can occur across gables and similar. (Particularly visible with externally rendered finishes).
Conventional placement of DPC through exterior skin commonly results in cracking along the bedding course.
If discharge routes for water are omitted, the conventional DPC approach retains water that can cause damp banding and staining.
This can be particularly noticeable where the wall has a rendered finish.
Where the cavity width changes or is impinged in any way, the placement of a Dropcloak ensures the damp protection integrity of the wall is not reduced or compromised.
The exterior skin in such situations is exposed to wetness both above and below the Dropcloak level. Thus it is acceptable for water within the skin to continue gravitating downwardly without the usual need for evacuation unless specific conditions exist.
By eliminating the need to build and support into both skins, installation is speedy and the problem should skins not offer matching or ideal alignment levels - does not even arise.
The approved Petheleyne Type CD Dropcloak is manufactured only by Cavity Trays of Yeovil and is accompanied with a performance warranty.