Vapour Control

Side Lap Details

Side laps are formed where the profiled edge of one sheet overlaps the edge of the adjacent sheet. Liner sheets are typically 0.4mm, or 0.7mm gauge. The joint is sealed by using an external tape, which is placed over the joint line of the cavity side of the liner sheet. The joint can be reinforced with stitcher screws or rivets, which are a requirement for some firewall constructions.
The use of a good quality sealant tape, such as Polyband, or T-foil, will produce a good quality air resistant joint. When using an external tape, it is important to note that stitchers will not provide an additional air-tightness, although they can add to the longevity of the joint.

End Lap Detail

End laps are formed where the profiled edge of one sheet overlaps the edge the adjacent sheet. Liner sheets are typically 0.4mm, or 0.7mm gauge. The joint is sealed using a sealant bead, which is placed inside the overlap joint. Fixings should be installed in the trough of each profile to provide compression of the sealant bead. The use of a good quality sealant bead will produce a good quality air resistant joint.