What fasteners should I use for flat roofing?
- Read time: 2 minutes
- Date: 21 May 2024
- Flat Roofing
Wondering what the difference is between fasteners for flat roofing? In this article we'll answer:
What is a flat roofing fastener?
Can I use a standard woodscrew or self-drilling fastener in a flat roof application?
How do I know which flat roofing fastener to use?
Can the same fastener be used for all flat roofing substrates?
What fastener should I use for fixing to a steel, timber, or concrete deck?
Can aluminium decks be fastened to?
What should I use for special decks that aren't mentioned above?
What fasteners do Fixfast offer?
What is a flat roofing fastener?
A flat roofing fastener is designed to work in combination with a tube washer or pressure plate to fasten both insulation and membrane to substrates within flat roofing applications. Varying in diameter, length, material, and head style; most suppliers in the industry offer fasteners to suit a wide range of applications too - including substrates such as concrete, steel, and OSB or plywood decks.
Can I use a standard woodscrew or self-drilling fastener in a flat roof application?
It's advisable to use fasteners that are fit for purpose to securely fix the build-up, which includes considering two vital features of a flat roofing fastener: the correct thread formation, and corrosion protection.
Tube washers and pressure plates are often used in flat roofing, and most standard woodscrews or self-drilling fasteners are unlikely to fit these plates and washers, especially due to the head style. Manufacturers offer fasteners that are compatible with the tube washers and pressure plates they supply.
If you're unsure of whether a fastener is suitable for your application, get in touch with your chosen specialist fastener manufacturer and they will be able to help.
How do I know which flat roofing fastener to use?
There are a few points you should take into consideration when selecting a flat roofing fastener.
These include:
What is the substrate you are fixing to?
Is it concrete? Or a light steel deck? Or a timber deck?
This will determine the drill point needed on the fastener that needs to penetrate the deck, and also any other tooling required - e.g. drill bits to pre-drill concrete
What are you fixing to the substrate?
E.g. insulation, or a PVC/SBS membrane
What material grade do you require?
Is it in a corrosive environment, such as a coastal region, or highly corrosive such as a swimming pool?
Does the fastener required need to be A4/316 grade stainless steel, or will carbon steel suffice?
What head style is needed?
Does it need to be compatible with a tube washer or pressure plate?
Will a countersunk or low-profile dome-headed fixing be needed?
Can the same fastener be used for all flat roofing substrates?
No, not necessarily. While there are flat roofing fasteners that suit multiple substrates (such as steel, timber, and concrete deck), it's important to use the correct fixing for your specific project. For instance, a fastener that is suitable for a concrete deck will have a different thread formation and drill point to a fastener suited to a steel deck (and vice versa) - which makes them incompatible with other substrates.
What fastener should I use for fixing to a steel, timber, or concrete deck?
Manufacturers have specific guidelines on which fastener to use in certain applications - seek technical advice if you're unsure.
Can aluminium decks be fastened to?
Yes, although the fastener will depend on the specific application (e.g. thickness and grade of the aluminium), and the building use. To prevent bi-metallic corrosion, a stainless steel fastener must be used.
Please note that it is not normally possible to use a threaded fastener on a thin aluminium deck, and a clamping fastener such as an aluminium peel rivet will need to be used.
What should I use for special decks that aren't mentioned above?
If you're fastening into an uncommon deck material and unsure of what to use, seek advice from your fastener supplier, as they'll be able to assist you with a solution.
What flat roof fasteners do Fixfast offer?
The Fixfast range of SureFast fasteners has been designed specifically for flat roofing applications.
