P E N E T R AT I O N S
NZ METAL ROOF AND WALL CLADDING CODE OF PRACTICE
6 V:2.2 PAGE 204
6.2.7 TYPE A SOAKER Soaker or underflashing penetration designs are those that drain at the plane of the roof pan. They are the preferred design and will produce a weathertight flashing in any circumstance where a hole is cut in metal roof cladding. For new installations the location of penetrations should be designed and the position known before the roof is installed. For safety and simplicity the safety mesh, underlay and roof cladding should be laid to cover the openings provided the sheets lengths covering the openings are increased by 150mm or the lap required to break the sheet at the head or back curb of the penetration. (See drawing 6.2.7.B) All soaker flashings have an overlap to mate with the side overlap of the profile, which ensures that even in an overflow situation, water ingress is avoided. It is highly unlikely that a penetration will be the exact width of the roof sheet so the preferred method of weathering is to cut full cladding sheets above the penetration and flash at the transverse lap. When penetrations line up with the ribs of the sheeting, the module of the roof cladding determines the width of the penetration.
5
4 1
Sheet 1 is full length
3
Sheet 2 is cut to the bottom of the penetration dimension Flashing 3 is the side curb Flashing 4 is the back curb Sheet 5 is cut to the top of the penetration cricket + 75mm
2
Drawing 6.2.7.A When the ribs do not align with the penetration, weathering can be achieved in several ways but the simplest and preferred method is to order longer sheets at the time of installation.
6 Sheet 1 & 2 are cut to the bottom of the penetration and 150mm minimum above the cricket
5 4
Flashing 3 is the side curb Flashing 4 is the back curb
2
Sheet 5 & 6 are cut to the top of the penetration hole and shaped to the cricket.
3 1
Drawing 6.2.7.B Š
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