Recommendations for Fixing Aluminium
- The front edge of the spouting or gutter must be higher than the crest of the roofing profile.
- Eaves flashings of painted or unpainted aluminium must be used. Underlay should terminate on the top of the eaves flashing.
- When re-roofing with aluminium, the existing support members must be inspected to ensure all staples, wire netting, nails, or other materials likely to damage the aluminium have been removed.
- Galvanised netting or mesh must not be in contact with the underside of aluminium roofs. If present, it must be separated by a 5 mm non-compressible barrier of inert non-absorbent, non-reactive material. Alternatively, self-supporting underlays may be used. Plastic strapping can be used for supporting underlays, stapled with stainless steel staples to the vertical face of the purlins.
- In a wet environment, aluminium must be separated from a corrosive surface such as concrete, butyl rubber, or CCA treated timber by using a 5 mm rigid strip of an inert non-absorbent material, an open woven geotextile layer, or PVC netting. Plastic coated steel netting is not recommended under aluminium sheeting.
- The design of the ceiling cavity must prevent the saturation of support members from internal or ground moisture. (See Internal Moisture.)
- All screws should be fitted with a profiled or bonded washer. Fixing screws shall be aluminium or Grade 304 stainless steel. Stainless steel screws must be fitted centrally through pre-drilled oversized holes (9 mm) for roofing and walls, regardless of sheet length.
- For sheet lengths over 10 m, the capacity to allow for thermal expansion must be in accordance with the tables in Thermal Expansion And Contraction.
Clause:
014_020_002_000_000_000_000_000_000
Clause Number:
14.20.2
/cop/installation/fixing-aluminium-sheeting#recommendations-fixing-aluminium
Revision Category:
1 - Minor Errata
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