Cavity battens

Cavity systems are used in the prevention of water damage to framework and interior cladding.

It is a second line of defence against water getting past the exterior cladding.

Another benefit to a cavity system is its prevention of moisture. Humid conditions cause moisture; this moisture could otherwise get trapped between the exterior cladding and internal framework. The cavity system provides space and allows air to circulate and create a drying effect. Moisture build up is also able to drain away down the vertical and diagonal slopping battens leaving the building through the holes in the vermin strip.

The battens are fixed at 600 centres to the studs.

The treatment of the battens is H3.1 minimum.

The size of the cavity batten we used was 40mm X 20mm, running continuous from the horizontal batten at the top of the wall vertically down to the vermin strip at the bottom. The battens need to be planed to slot in nicely to the vermin strip.

The continuous horizontal cavity batten at the very top of the wall will prevent air getting into the roof space.

On the unitec house we used slightly smaller cavity battens to the sides of  the doors and windows, and on each corner of the house to allow for the corner flashings.

We fix the cavity battens at 300mm spacing (hammer length) with galvanised flooring nails.

We cut a notch above the windows and doors on either side of the cavity battens to allow for the vermin strip and flashing to be installed.

The flashing gets fixed to the building paper on the lintel with Alu band and against the top of the window or door.

The vermin strip then gets stapled above the flashings at least 25mm above the flashing.