Code of Practice v3.0 Online
The NZ Metal Roof and Wall Cladding Code of Practice is a comprehensive design & installation guide, and a recognised related document for Acceptable Solution E2/AS1 of the NZ Building Code.
The weathertightness of a flashing is determined by the flashing cover (C), not the flashing dimension.(D) Other considerations are catchment area, wind exposure, roof pitch and profile height.
The minimum flashing cover (C) must correlate with the tables below.
There are three categories of exposure or pitch that determine the required flashing cover .
Category A:
- Low, Medium or High Wind Zones, all pitches
- Very High and Extra High Wind Zones where the pitch is equal to or greater than 10°.
Category B:
- Very High where the pitch is less than 8°, and
- Extra High Wind Zones all pitches.
Category C:
- SED Wind Zones up to 60 m/s all pitches.
NOTE: These tables are relevant to trapezoidal profiles with a rib height of 25 – 34 mm and standard corrugate. Longitudinal Apron flashings over profiles with a rib height greater than 34 mm may have one rib overlap
8.3D
|
| Category |
|
|---|---|---|---|
| C1 | 130 mm | 200 mm | 200 mm + baffle |
| Ridge Type | Standard | Wide | Wide |
| Purlin Position X | |||
| Pitch 8°–15° | 165 mm | 150 mm | 150 mm |
| Pitch 15°–30° | 150 mm | 200 mm | 200 mm |
| Pitch 30°–45° | 130 mm | 180 mm | 180 mm |
8.3F
|
| Category |
|
|---|---|---|---|
| C2 | 1 rib | 2 ribs | 2 ribs |
| C1 (smooth surface) | 50 mm | 75 mm | 75 mm |
| C1 (profiled surface) | 75 mm | 100 mm | 125 mm |
8.3H
|
| Category |
|
|---|---|---|---|
| C2 | 2 crests | 2 crests | 3 crests |
| C1 (smooth) | 50 mm | 75 mm | 75 mm |
| C1 (profiled) | 75 mm | 100 mm | 125 mm |
8.3J
|
| Category |
|
|---|---|---|---|
| C1 (smooth surface) | 50 mm + hem or 75 mm | 75 mm + hem or 100 mm | 100 mm + hem or 125 mm |
| C1 (profiled surface) | 75 mm + hem or 100 mm | 100 mm + hem or 125 mm | 125 mm |
| C2 | 130 mm | 200 mm | 200 mm + baffle |
8.3L
|
| Category |
|
|---|---|---|---|
| C2 | 1 rib | 2 ribs* | 2 ribs |
| C1 (smooth surface) | 50 mm + hem or 75 mm | 75 mm + hem or 100 mm | 100 mm + hem or 125 mm |
| C1 (profiled surface) | 75 mm + hem or 100 mm | 100 mm + hem or 125 mm | 125 mm |
*Not to exceed 300 mm. Two ribs cover can consist of two machined crests or one machined crest plus an upstand, hand-formed from the adjacent pan.
8.3N
|
| Category |
|
|---|---|---|---|
| C2 | 2 crests | 2 crests | 3 crests |
| C1 (smooth surface) | 50 mm + hem or 75 mm | 75 mm + hem or 100 mm | 100 mm + hem or 125 mm |
| C1 (profiled surface) | 75 mm + | 100 mm + hem or 125 mm | 125 mm + hem |
