Hail is potentially a more serious leakage problem than snow in N.Z. , because it is not restricted by altitude or zone, and by accumulating at valleys and gutters, it can cause blockage and subsequent leakage.

For this reason all sumps and rainwater heads should have leaf guards that effectively offer a large free area of outlet and should not be of a tapered design , because of the wedging action of the hail. Because hail can effectively block any overflows, external gutters should be installed with the back lower than the fascia board or cladding to avoid water overflowing into the building.

In hail prone areas, a baffle should be provided at the gutter purlin to allow melting water to escape.

Hail can be prevented from blocking a gutter by install ing a 50 mm x 50 mm hot-dipped galvanised or aluminium RHS bearer , fastened to the penultimate purlin fastenings i (see detail 4.8.4.B. ), to which is attached a proprietary galvanised plank or expanded metal walkway mesh.

Where areas are continually subjected to hail, gutter hail baffles must be provided. Timber must not be used.

Snow/Hail Board

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Revision Category: 
0 - Clause Removed
Revision Detail: 

Clause removed combined with Hail.

Draft Clause: