For those who plan to carry out construction or repair of the roof, information on self-tapping screws for roofing from corrugated board will be useful. First, let's deal with terminology. A self-tapping screw, in other words, a self-tapping screw is a fastener made in the form of a steel rod with a triangular thread, having a metal head. Unlike ordinary screws and screws, here the thread covers the entire cylindrical surface of the rod.
Main characteristics
From the corrugated board (profiled sheet), a protective and decorative roofing is mounted, as well as fences and walls of buildings made of various materials are lined. On sale there is a wide range of self-tapping screws designed to fix profiled sheets to metal and wooden surfaces. There are a number of differences in the design and calculation of the number of fasteners depending on the type of work, so it is very important to correctly choose them. All these subtleties directly affect the strength and reliability of the lining fastening.
Such fasteners are made of steel:
- galvanized carbon;
- with stainless coating.
Self-tapping screws are equipped with neoprene gaskets that prevent moisture from entering the element head, eliminate the corrosion process and make it possible to dispense with washers, which usually serve as additional gaskets.
So that the roof structure or fencing does not lose its decorative appeal, some manufacturers paint the fasteners for corrugated board with a special polymer-based paint in tone to the main facing material. In addition to the aesthetic component, polymer paint performs a protective function, protecting the metal part from rust and prolonging its operational period. Modern self-tapping screws can last at least half a century, and most importantly, the entire roof structure substantially depends on their quality characteristics.
Types of screws
There are three types of self-tapping screws designed for fastening profile sheet material:
- Fixing the trim to the wooden crate. Their feature is a rare step between the threads, which allows you to work with hardwood and provides a firm hold.
- For metal substrates and structures installed in regions with increased wind load. By analogy with the first option, there is a rare thread pitch and stainless steel. But there are some differences, such as a special method of sharpening the tip, which allows you to maintain the integrity of the processed material without cracks and nicks.
- For fixing the extension and ridge elements when installing the roof. Such self-tapping screws have an increased length.
All three types of self-tapping screws are available with a drill-tip, which allows you to do without preliminary drilling holes. The hexagonal head makes it possible to reliably fix the fasteners in the cartridge holder of the power tool, which significantly optimizes the work, saves time and improves the quality of the procedures performed.
Fixing process
Installation of corrugated board on the seats is carried out using self-tapping screws with a galvanized surface or with polypropylene washers. The diameter of the fasteners can vary between 0.48 - 0.63 cm, with a length of 1.9 - 25 cm. When purchasing fasteners with thread, remember that their length should be 3-4 mm longer than the thickness of the roofing materials to be joined. The consumption of fasteners is calculated at the rate of 6-8 pcs per 1 m² of roof.
In order to ensure reliable fastening of one cladding sheet on a straight section of the roof, 6-8 self-tapping elements are required, which are installed every 50 cm.
As you approach the roof ends, the screw consumption must be increased, thereby minimizing the detrimental effect of the wind load on the roof structure.
When installing fences, 6 self-tapping elements will go on one profiled sheet, and to increase the strength of the fence, increase their number and fix each wave of corrugated board. If you plan to clad a wall, fastening is carried out through a wave along the lower edge of the material. Vertical joints are machined with rivets specially designed for such purposes.
Calculation of the weight of self-tapping screws and their cost
The weight of the fasteners is calculated based on their dimensions (length, diameter), and such a parameter is measured in kg per 1000 pcs. One thousand threaded screws can weigh from 18.5 kg to 41.7 kg, which will directly depend on their length. Prices for products intended for fixing profile sheets to the roof surface range from 1.7 to 3 rubles / pc. More expensive items are covered with polyester material and prices start at 3 rubles / pc. Samples with a protective coating tinted on the RAL scale (at least 8 rubles / pc) will cost even more.
Consumption of fasteners for fixing corrugated board
Before starting work, determine how many fixing screws are needed for the entire area of the roof or fence. In the standard approach, without additional requirements, 9 pcs of screws per profile sheet are usually used.. As it becomes clear, when multiplying the required amount of facing material by 9, we will find out how many metal clips are needed for high-quality installation. Naturally, the sheets of corrugated board are stacked one on top of the other, which means that in fact we need fewer fasteners than was calculated, but this creates a stock of material that can be lost during the work process.
You do not need to carefully consider each screw, especially since they are packed in factory containers and sold by weight. On the label that accompanies the product, the exact weight and number of units are indicated, we add from ourselves that 1000 self-tapping screws of the minimum size weigh 3.45 kg, and the largest - 45 kg.
If you are not too lazy and approach the process of choosing fastenings for corrugated board with all responsibility and carefully calculate their consumption, then the roof structure will be reliably sheathed with metal sheet material and will serve you for decades without damage and repair.