Compatibility & Fixings

Fixing patterns are also shown in the in the drawings section of Calder Stewart Roofing’s Specific Profile Technical Data Sheets section of this website and are for all locations except for Very High and Extra High wind zones. In these cases specific information on fixing patterns should be obtained. Where sheet lengths are in excess of 12 metres, roofs are to be pre-drilled for the first 12 metres with 5-6mm holes and then 12mm holes for the remaining roof, to allow for the profile and EPDM washers for all remaining purlins. Sheet lengths over 24 metres require specific design by Calder Stewart Roofing Ltd.

Compatibility of fixings is a major issue and care must be taken to prevent corrosion cells being introduced by the use of incorrect fixings which may either fail prematurely or cause damage to the surrounding material. The Fixing Material Selection Chart (right sidebar - this page) offers comprehensive recommendations for the correct fixings type when used in various environments and with the specific range of materials offered by Calder Stewart Roofing. Note that the table excludes hidden fixings which are protected from the environment.

In addition, ColorCote® recommends specific fasteners where self drilling screws are required - see ColorCote® Recommended Fasteners (right sidebar - this page).

Information shown in the Compatibility Table (right sidebar - this page) is for common materials likely to receive run off or be in contact.

Other materials may cause local or wide spread corrosion and invalidate any warranties. In addition, combinations of pollutants, environments and specific contact materials may cause additional effects and specific consideration should be given to:

• Constantly wet areas or ponding
• Carbon including coal and soot or other chimney outfalls
• Specific products or chemicals from manufacturing systems (e.g. fertiliser)
• Leached materials (e.g. copper from treated timber)

Where likelihood of non-compatible materials exist such as galvanised TV aerial mountings to a pre-painted Zincalume roof are likely to occur and substitution of product is not possible, then physical separation with an isolating material should be considered. Isolating materials include:

• Butyl Rubber
• Neoprene (with a low carbon content)
• GRP and PVC

Where separating or barrier materials are used, close attention to the correct use of fixings, clearance holes and possible run off should be considered.

Note: If in doubt contact Calder Stewart Roofing Support for specific advice.