It is imperative when using superior corrosion-resistant steel roofing, cladding and accessory materials that the performance of the fasteners used to fix these materials have the same or superior service life. Specifying the correct fasteners for these projects is critical for long term performance and aesthetics.
There are two fastener designs to be considered for use with Safintra’s materials:
- Fixtite ™ self-drilling screws for fastening cladding to a building structure.
- Accessory fasteners for fastening roofing accessory items such as flashings.
Where accessory fasteners such as pop rivets are required, they should be manufactured from Aluminium when fastening Aluminium Zinc coated steel. In the case of stainless steel, compatible stainless steel pop rivets must be used.
For concealed fix applications, nothing less than Class 3 is recommended.
CHOOSING THE CORRECT CLASS OF FASTENER
The Fixtite™ fastener application guide table gives a general guide to the fastener metal type recommended for various Safintra steel roofing products. In the interest of quality assurance it is essential that fasteners used comply with the South African National Standard SANS 1273:2011.
Fasteners containing elements of stainless steel, Lead, Copper, and Copper containing alloys (such as MONEL) should not be used in conjunction with Aluminium-Zinc coated steel or pre-painted steel.
WASHERS USED WITH FASTENERS
The rubber washer component of self-drilling screws must be manufactured from materials compatible with the roofing material.
Washers containing significant levels of conductive Carbon black fillers are NOT suitable for use with Aluminium-Zinc alloy coated and pre-painted Aluminium-Zinc coated products, particularly in marine environments. Therefore fasteners must be assembled with Carbon-black-free washers.
In certain applications the fastener may be exposed to a greater risk of corrosion as a result of specific environments (e.g. high condensation and specific service environments such as intensive animal farming). Under the South African National Standards, corrosion classification is based on the fastener heads rather than the shanks. It is advisable to enquire about the fastener’s porosity rating if intended use will be under service specific conditions.
FIXTITE FASTENER APPLICATION GUIDE
All Fixtite™ fasteners carry a manufacturer’s warranty and comply with SANS1273-2011 (AS3566-2-2002) Standards. All Safintra roof systems will only be warranted if installed with Safintra-approved fasteners.
- All Safintra Fixtite™ fasteners provide optimal service life with Aluminium-Zinc coated steel.
- Different lengths/types of fasteners are available on request, including stainless steel.
- For optimal performance, the service life warranty of fasteners must match the service life warranty of the sheeting.
- Only Class 3 (concealed fix) and Class 4 fasteners are suitable for use with Aluminium-Zinc coated steel (unpainted or pre-painted).
- Class 4 coastal application should be discussed with Safintra’s technical team for guidance.
- Only use stainless steel fasteners for Aluminium sheeting.