Compatibility of Direct Contact Between Metals or Alloys
| Roof Drainage System Components and any Cladding Material | Accessory or Fastener Material | |||||||||||||||||
| ZINCALUME® Steel | Galvanised Steel | Zinc | COLORBOND® Steel (Plus Ultra, Metallic & Matt) | SuperDura™ Stainless Steel | Stainless Steel (300 series) | Aluminium Alloys | Copper and Copper Alloys* | Lead2 | ||||||||||
| Atmospheric classification | ||||||||||||||||||
| SI and VS | Mild | SI and VS | Mild | SI and VS | Mild | SI and VS | Mild | SI and VS | Mild | SI and VS | Mild | SI and VS | Mild | SI and VS | Mild | SI and VS | Mild | |
| Aluminium Alloys | No4 | No4 | No4 | No4 | No4 | No4 | No4 | No4 | No4 | No4 | Yes3 | Yes3 | Yes | Yes | No | No | No | No |
| ZINCALUME® Steel | Yes | Yes | Yes1 | Yes1 | Yes1 | Yes1 | Yes | Yes | No | Yes | No | Yes | Yes | Yes | No | No | No | No |
| Galvanised Steel | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes | No | Yes | Yes | Yes | No | No | No | Yes |
| Zinc | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | No | Yes | No | Yes | Yes | Yes | No | No | No | Yes |
| COLORBOND® Steel (Plus Ultra, Metallic & Matt) | Yes | Yes | Yes1 | Yes1 | Yes1 | Yes1 | Yes | Yes | No | Yes | No | Yes | Yes | Yes | No | No | No | No |
| SuperDura™ Stainless Steel | No | No | No | No | No | No | No | No | Yes | Yes | Yes | Yes | No | No | No | No | No | No |
| Stainless Steel (300 series) | No | No | No | No | No | No | No | No | Yes | Yes | Yes | Yes | No | No | No | No | No | Yes |
| Copper and Copper Alloys | No | No | No | No | No | No | No | No | No | Yes | No | Yes | No | No | Yes | Yes | No | Yes |
| Lead2 | No | No | No | Yes | No | Yes | No | No | Yes | Yes | Yes | Yes | No | No | Yes | Yes | Yes | Yes |
Legend:
SI, VS, Mild = Severe industrial, very severe and mild classifications (see AS/NZS 2312).
Yes = Acceptable - as a result of bimetallic contact, either no additional corrosion of rainwater goods will take place, or at the worst, only very slight additional corrosion. It also implies that the degree of corrosion would not significantly shorten the service life.
No = Not acceptable - moderate to severe corrosion of rainwater goods will occur, a condition which may result in a significant reduction in the service life.
Note:
- Unpainted zinc-coated steel and zinc are suitable for direct contact but should not receive drainage from an inert catchment.
- Due to its toxicity, lead is not recommended for rainwater goods.
- Fixings only.
- Our experience is that these materials are not compatible in corrosive environments so our advise differs from AS/NZS 3500.3:2015 Table 4.4.1
Acceptability of Drainage from an Upper Surface to a Lower Metal Surface
| Lower Roof Drainage System Material | Upper Cladding or Roof Drainage System Material | |||||||||
| ZINCALUME® Steel | Galvanised Steel | Zinc | COLORBOND® Steel (Plus Ultra, Metallic & Matt) | SuperDura™ Stainless Steel | Stainless Steel (300 series) | Aluminium Alloys | Copper and Copper Alloys | Lead2 | Glazed Roof Tiles, Glass and Plastic | |
| Aluminium Alloys | No4 | No4 | Yes | No4 | Yes5 | Yes5 | Yes | No | No4 | Yes |
| ZINCALUME® Steel | Yes | Yes | Yes | Yes | Yes5 | Yes5 | Yes | No | No | Yes |
| Galvanised Steel4 | No | Yes | Yes | No | No | No | No | No | Yes5 | No |
| Zinc | No | Yes | Yes | No | No | No | No | No | Yes5 | No |
| COLORBOND® Steel (Plus Ultra, Metallic & Matt) | Yes | Yes | Yes | Yes | Yes5 | Yes5 | Yes | No | No | Yes |
| SuperDura™ Stainless Steel | Yes5 | Yes5 | Yes5 | Yes5 | Yes | Yes | Yes5 | Yes5 | Yes | Yes |
| Stainless Steel (300 series) | Yes5 | Yes5 | Yes5 | Yes5 | Yes | Yes | Yes5 | Yes5 | Yes | Yes |
| Copper and Copper Alloys | Yes5 | Yes5 | Yes5 | Yes5 | Yes5 | Yes5 | Yes5 | Yes | Yes | Yes |
| Lead2 | Yes5 | Yes5 | Yes5 | Yes5 | Yes5 | Yes5 | Yes5 | Yes5 | Yes | Yes |
Legend:
Yes = Acceptable - as a result of bimetallic contact, either no additional corrosion of rainwater goods will take place, or at the worst, only very slight additional corrosion. It also implies that the degree of corrosion would not significantly shorten the service life.
No = Not acceptable - moderate to severe corrosion of rainwater goods will occur, a condition which may result in a significant reduction in the service life.
Note:
- Unpainted zinc-coated steel and zinc are suitable for direct contact but should not receive drainage from an inert catchment.
- Due to its toxicity, lead is not recommended for rainwater goods.
- Fixings only.
- Our experience is that these materials are not compatible in corrosive environments so our advise differs from AS/NZS 3500.3:2015 Table 4.4.1
- Although drainage between the materials shown would be acceptable, direct material contact should be avoided.
Legend
Mild, SI, VS, = mild, severe industrial, and very severe classifications (see AS 2312:2002 & AS 2311:2000).
Notes:
1. Due to its toxicity, lead is not recommended for rainwater goods
2. Unless adequate separation can be assured, pre-painted rainwater goods should be considered in terms of the base metal or coated steel.