NHBC section 6.6 provides guidance under 6.2(d) on how a party wall should incorporate a channel to prevent water that accidentally spills or floods within one dwelling from permeating an adjoining dwelling. However in practice, if perimeter radon/methane barriers are present in the exterior walls, the channel ends are obstructed and the arrangement cannot function.

The Type PWRB Rising Party Wall Barrier provides an alternative approach. The base of the barrier acts as a dpc and extends under both skins of the party wall. The upstand acts as a dam against water flooding from within one dwelling contaminating the adjoining dwelling. The upstand is capable of holding back a far greater volume of water than a channel.

Because the profile extends upwards instead of downwards, it can oversail and interface with commonly used perimeter gas barriers. Any water can thus be directed safely into the lower portion of the perimeter wall gas barrier, from which subsequent evacuation is via the already present barrier caviweeps. At all times the gastight integrity can be maintained.

The Party Wall Rising Barrier eliminates the problem of incompatibility, increases the capacity to prevent inter-property water contamination and satisfies the design detail requirement.