General Advice for the fixing and installation of Vapour Control and Breather Products

General

Vapour control and breather membranes are secondary performance layers fixed within the building structure. Their prime function is controlling vapour movement through the building structure when built. If a building is to be left unfinished for any length of time, consider providing additional temporary weather protection to uncompleted parts of structure.

Breather Membranes

Fix on the cold side of insulation with staples or large headed clout nails. Fix in single layers over sheathing. Use two layers over open stud-work. Mark stud positions for wall tie fixing.

Lap should be

Horizontal	100mm minimum
Vertical	150mm minimum

Upper layers should lap over lower layers to direct moisture away from joints. Stagger vertical laps where possible. Protect lowest timbers against rising moisture. Fix a 150mm strip behind all exterior trims and openings. Tape joints to minimise wind flog damage. Do not leave exposed for long periods. Cover as soon as possible to minimise the risk of wind damage.

Vapour Control Layers

Fix to the warm side of insulation with staples. Ensure continuity of the membrane with a 100mm lap at joints. Tears and splits should be repaired with an overlay of the same material. Tapes seal all joints with a foil faced tape.