Flashing Buckling Due to Thermal Movement

It is necessary to make provision for thermal movement of pierce fixed flashing when long lengths are used, and end laps joints are required. To some extent the spacing of expansion joints will also depend on the accessibility of the roof for inspection and maintenance, the visibility of the joint, and the consequences of leakage through a failed joint.

Inadequate provision for expansion can also cause roof noise.

E2/AS1 requires expansion joints in steel flashings at 8 metre centres for dark coloured steel flashings, and 12 metres for light, although this is inconsistently policed. The expansion joints detailed in E2/AS1 and the old Code of Practice are 3-piece methods, that have proven unpopular with installers who consider them overly complex.