Farmer screws, commonly known as farmers or self-tapping screws, are a type of specialised fastener used to fix steel roofing to wooden structures. Self-tapping screws and metal roofing tile make an inseparable pair and guarantee the safety and functionality of the roofing.
Features of screws for sheet metal
Farmer screws are produced by Klimas Wkręt-met and are offered in a wide range of RAL colours. This feature is extremely important in the case of the installation of metal roofing tile, as the aesthetics of the covering, which includes not only the profiling but also the colouring, is extremely important to investors. Today the sheet metal roofing market is extremely wide. Metal roofing tile producers offer visually appealing sheet metal profiles and clearly specify how to install them. Self-tapping screws act as fastening elements regardless of whether it is a concealed or visible installation. It is becoming increasingly common to see roof coverings where the screws for sheet metal are concealed under the roof sheathing. This solution is more aesthetically pleasing and the roof surface is not disturbed by the fasteners. The classic installation focuses on the correct distribution of the farmers over the entire roof surface so that they are correctly and permanently connected to the structure.
Correct installation = safety
The metal roofing tile, whether cut to size or in the form of handy single-module or double-module sheets, is screwed to the roof battens with farmer screws. Whether it is installed from top to bottom, which is possible for some products, from left to right and vice versa, or in a passing pattern, the fixing of the sheet to the substrate is crucial. Self-tapping screws of the farmer type have a self-drilling tip, which allows the screw to drill through components with a total thickness of up to 2.5mm in one screwing. EPDM washers, under the influence of pressure and heat, seal the created hole, protecting the attic from leakage. The number of screws for metal sheet varies and depends on the type of roofing and the specifics of the metal roofing tile. A generally accepted rule of thumb is that for every 1 m², 8 to 12 screws are used. Screws are customarily placed in every second wave hollow or specially pressed mounting holes. Vertical embossments that require connections are stapled with shorter farmers. An extremely important step in making a roof covering is to read the metal roofing tile producer’s installation instructions. The variety of materials available on the market means that the nuances that distinguish products from each other affect their correct installation. Both high-class products and their proper installation are a guarantee of safety for householders.
Installation of roof service catwalk
Roof service catwalk refers to all the elements of the roof that allow you to move around the roof to reach chimneys, vents and aerials. Failure to install service catwalk will result in damage to the roof covering when moving across it. Properly installed service catwalk ensures safe use even in winter. The service catwalk is screwed to the rafter framing or battens according to the installation instructions using wood farmer screws. The service catwalk requires excellent workmanship and it is therefore necessary to choose the correct length of screws. Typically, 60mm self-tapping screws are used to fasten the service catwalk.
Offer of farmer screws
The range of screws offered by Klimas Wkręt-met includes farmer screws covered with a 12μ anti-corrosion coating of galvanic zinc. The process of galvanising involves immersing a steel element in an electrolyte bath containing zinc compounds. When exposed to conductive currents, the zinc particles settle on the steel and are then subject to passivation and rinsing. Galvanisation makes the coated surface of the screw smooth and uniform. It has no ridges or laps, making it easy to screw into wooden structures. Due to the multitude of applications and the differences in the thickness of the material and what is installed to the roof structure, farmer screws are offered in lengths from 25 to 100 mm.
Farmer screws for the home do-it-yourselfers
Self-tapping screws are not only used by professionals carrying out commissioned roofing work. They are often used for domestic work. Doing simple wooden structures yourself is a very common and popular job for home DIY-ers. Depending on the material being worked with, the correct selection of fastening elements is essential. Farmer screws will prove useful wherever you have a connection between sheet metal and wooden structure. An example application is the covering of a gazebo or backyard woodshed with weather-resistant sheet metal. Even a small roof covering requires a good selection of not only the length of the screw, which should penetrate the wood along the entire thread length on one side, but also the appropriate number of screws. If the sheeting is too weakly fixed, it can have serious consequences in terms of tearing it off during a gale. A frequent use of farmer screws is the self-assembly of shelters built-up with sheet metal or security with simple sheet metal flashings. Trapezoidal sheeting, which is often used, should be screwed in the lower pitch of the wave so that there is no void between the screw head and the wooden structure. Remember that a larger sheet, placed vertically, will have a higher load-bearing capacity and therefore needs a strong fixing.
Read the instructions
Reading installation instructions is not popular. Unfortunately, it is compulsory for most of the key stages of construction, and roofing installation is certainly one of them. In the instruction material, producers point out most of the critical issues and give clear guidelines on how, with what and where to install. Proper selection of farmer screws for wood structures involves both their correct positioning and the right length to guarantee a sufficiently strong connection to the substrate. However, there are fundamental differences in the case of variable sheet metal products. Properly performed work will also make it possible to maintain the producer’s guarantee on the material supplied. It is worth noting that improper installation of the roofing is often the reason for rejecting a claim. Nowadays, products have very long guarantee periods, so there is a lot to take care of. Works should always be carried out in accordance with the art of construction and, above all, by proper execution, have an excellent effect that guarantees safety and aesthetics.
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