Roofing screws

High quality sheet roofing materials alone do not guarantee a reliable roof covering. Precise compliance with installation technology and the use of correct fasteners are also important. Roofing screws are used for this purpose, differing in size, material, corrosion protection method, design and color.

A roof covering reliably protects a building from precipitation and wind only when its components are securely fastened to the base. A roofing screw not only fixes flexible shingles or metal profile sheeting, but also creates a sealed joint through which moisture cannot penetrate under the covering.

Types of roofing screws

Roofing fasteners are manufactured from two main types of steel alloys. These are standard alloyed steel with a zinc-plated coating for corrosion protection, and the more expensive and practical option — stainless chromium-nickel steel, which is not subject to rusting and has a long service life. In addition, screws for fastening roofing materials differ in other characteristics:

1. The head shape can be made as a hemisphere combined with a press washer to increase the bearing area. The head is fitted with a slot or cross recess for a screwdriver or power driver bit. Another head configuration is a cylindrical hex for working with a wrench or a special power tool bit. These products are fitted with a metal washer with a rubber or caoutchouc backing. The most effective material for this purpose is considered to be self-vulcanizing EPDM rubber about 3 mm thick.
2. The next distinguishing feature is the design of the screw’s working tip. It can be made as a point or end in a drill bit. Pointed screws are intended for working with a wooden base, while drill-tip ones are for metal.
3. Thread pitch frequency. Roofing screws with a coarse thread pitch are used for wood, while those with a finer thread are used for metal structures. This refers to the base to which the roof covering is fastened.
4. Head color. The heads of zinc-plated screws are painted in colors according to the RAL color spectrum, matching the shade of the roofing materials. Weather-resistant paints are used, serving as additional corrosion protection for the fastener.

The length and thickness of roofing screws vary over a wide range. For metal, a length of 28-35 mm is optimal, while a wooden base may require fasteners up to 150 mm long. The thickness of a roofing screw ranges from 4.8 mm to 6.3 mm.

Some useful characteristics of roofing screws

The required number of fasteners depends on the base structure, size and quality of the roofing material. On average, fastening 1 m² of corrugated sheeting may require 5-8 screws, while metal tile may require 8-10 pcs/m².

The weight of screws is normatively defined per 1000 units. This is a reference value, specified in the appendices to the standards. For example, a roofing screw with a drill tip measuring 4.8×38 weighs 6.0 kg per 1,000 pcs.

When choosing roofing screws, attention should be paid to markings — they help distinguish original products from counterfeits. The mark is stamped on the head of each item. The quality of the rubber backing is also important, since this element is responsible for the joint’s seal throughout the entire service life.

Installation features of roofing screws

Fixing the covering materials is done with a power driver fitted with a bit matching the shape and size of the screw head. Pre-drilling of holes is usually not required, and no other tools (drill, hammer drill) are needed.

Fastening of corrugated sheets can be done either at the bottom of the wave or at the crest. The main thing is to correctly select the screw length. When driving in, the screw should be positioned strictly vertically, making sure the rubber gasket is compressed by no more than 50%. If this condition is not met, insufficient tightening makes the joint vulnerable to moisture, while excessive tightening deforms the gasket, which also reduces the seal’s tightness.

FLOK supplies roofing screws according to a variety of requirements.