Roofing Bolts: A Buyer’s Guide

roofing bolts

Across all different sectors of construction and industry, fixings are required to keep structures strong and secure. The nut and bolt method of fixing is widespread across the industry but when it comes to fasteners for specific projects, the choice can become difficult.

Find out below why roofing bolts are one of the best fixings for your projects and how they can help improve your proactivity.

What are roofing bolts used for? 

Roofing bolts are actually made to be used in lots of different applications other than roofing. While they are ideal for joining metal to metal, they also work for other construction materials. Primarily we supply these bolts for fitting cable tray and trunking.

They are designed with a large flat head because the wide surface on that head allows the holding force to be spread further than a standard bolt. This means a more secure holding. Damage to the material is also reduced as the stress/tension spreads throughout the bolt.

Typically, roofing bolts are fully threaded which makes them even more suitable for diverse applications as they can join thin or thick materials, dependent on how far the bolt needs to be installed.

With this in mind, when deciding on materials for a project, contractors should look toward roofing bolts as the solution to solving the demands of multiple fixtures.

How to fit gutter bolts? 

Roofing bolts, also known as gutter bolts, are notoriously fiddly to use because of the different parts that need to be juggled during application. Finding a fixing that has a flange nut and a pozi suitable head reduces hassle as you’ll need minimal tools and minimal effort when working on a project. Not only does this make a job run more smoothly, but it also makes the entire fixing process quicker.

The nut can be inserted securely behind the cable tray or trunking and a few twists with a screwdriver can relieve the pressure on the worker. The wide flatheads can also be used with Philips or flat screwdrivers.

But what can make the process of fitting roofing bolts even easier?

A quick way of tightening the bolt is to use a good pair of mole grips on the thread of the bolt and spanned. The spare threads can even be snapped off with the mole grips. Then all they’ll need is a quick file.

Make sure the threaded shaft protrudes all the way through the bottom of the tray as cable could catch on the threads if installed wrong.

A perk of flathead bolts is that it means the cable sheaths can’t tear against them during installation. This will reduce replacement costs and downtime due to damaged equipment.

stainless steel fixings

Types of roofing bolts 

Like any fixing, different types are more suited for different applications. The type can depend on the weight of the application, the location and also the budget.

HDG Roofing Bolts

HDG stands for Hot Dipped Galvanised. Hot-dip galvanizing is a process developed to prevent steel from corroding.

Galvanized fixings have an easy-to-clean surface so remain maintenance-free for longer (depending on the environment it is being used in). Galvanised fixings should be kept away from very high temperatures (over 200ºC) as there are concerns with operating above this high-temperature limit. Doing so may lead to peeling, adjustments in mechanical properties, corrosion protection reduction.

This makes these bolts diverse for different applications—especially those that are harder to get to as maintenance isn’t required regularly. It also means they can be used where rusting or corrosion would be a problem.

Stainless Steel Roofing Bolts

Many of the perks of stainless steel bolts are because of the attributes s/s possesses.

Stainless steel is a corrosion-resistant material which means it has an excellent life cycle and won’t wear in an environment with poor weather or salt content in the air. This means that structures fitted with stainless steel fixings are maintenance-free and won’t cost on bolt repairs frequently in the long-term.

Stainless steel is also a green product. It is 100% recyclable, as it is not coated with any toxic material it does not produce toxic run-off. Should you need to replace the bolts or get rid of them, they can be used again in the future.

Stainless steel is also resistant to high heat and cold temperatures. This means that this type of roofing bolt can be installed almost anywhere corrosion or temperature fluctuation could occur.

Tray Roofing Bolts

Tray roofing bolts are fast fixing. Their flange nut and flathead (pozi screwdriver compatible) means that labour time is saved because it just requires a few turns of the wrist rather than a fiddly tightening process.

steel bolts

Roofing bolt sizes 

As roofing bolts are versatile, it’s obvious that they would be available in different sizes to suit different applications and fixtures.

The first number in a metric bolt size refers to the bolt’s outer diameter. For example, a bolt specified as “M6 x 30” fits a 6mm diameter hole. The “M” indicates that it is a metric size.

The length of the rod follows in millimetres. The size of the nut will also be M (followed by a number) and this has to match up with the thread diameter in order to create the tightest seal.

Metric nut sizes can go all the way from 2mm to 20mm but these are rare for roofing bolts. The most common sizes for roofing bolts are M5, M6 and M8 as these meet the hole sizes of most cables tray and trunking.

Armafix stock M6 roofing bolts. The length of the bolts run from M6x12 up to M6x60 dependent on the specifications of your project.

The correct length is important to get appropriate thread engagement. This is important because it impacts the integrity of the joint. Too little thread engagement and the nut may have a tendency to strip out at lower than desirable torques.  Too much thread engagement and the torque needed to drive the screw will tend to be high, which can lead to poor clamp load or even breaking fasteners during assembly.

cable tray bolts

Best prices on roofing bolts

If you need to buy roofing bolts for your next project, Armafix has the solutions. Our roofing bolts are all flathead for easier and faster use which lower time required fussing over fixings. Our diverse range of lengths also means you can use your measurements against our fasteners to get the best fix.

Not to mention we stock in big pack quantities with low prices to help your project stay on budget and with reduced downtime. Never run out of fasteners again.

So if you need a great price on roofing bolts for your next project, contact Armafix now on 0113 256 7211 or email

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This article was written by Terry Harmer, Managing Director at Armafix, who has several years of experience of supplying quality fixings and support solutions for the building services industry.

Armafix, Managing Director, fixings, screws, fasteners

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