Double-threaded screws (also known as double-threads) are mounting elements widely used in the PV industry. They are used to install photovoltaic panels on building roofs. The double-threaded screw should be made of corrosion-resistant materials, such as stainless steel, to serve for many years in difficult environmental conditions, ensuring full mounting stability. Are you planning to install PV panels and don't know which double-threaded screw to choose? Take advantage of the tips of Onninen experts and conveniently order the products you need.
Check out double-threaded screws at the Onninen wholesaler
How to choose the size of double-threaded screws for photovoltaics?
Double-threaded screws for mounting PV structures have two types of threads. The first one allows screwing to the rafters through the roofing, and the second one - metric - is used to screw the rails and brackets. The available models differ in several key parameters, primarily length and diameter/size of the metric thread. Popular variants are:
- M10 double thread screw ,
- M8 double thread screw ,
- M6 double thread screw ,
- M12 double thread screw .
M10 double-threaded screws of various lengths are mainly used to attach the mounting profiles of PV installations. The M10 threaded screw is used to fasten the structure to the roof covering, among others. on a roof covered with sheet metal, metal roofing tiles, tar paper or bituminous shingles.
Installation of photovoltaics on the roof with double-threaded screws
Photovoltaic panels are mounted on roofs using various types of fasteners. The basis is long double-threaded screws. They ensure that the entire structure holds stably to the truss and frame. The set of a double-threaded screw usually includes: a set of nuts, a gasket and a mounting adapter. Seals ensure the tightness of the hole made in the roof covering. The nuts support optimal distribution of forces over a larger surface and prevent deformation of the covering. The adapter allows you to connect the screw to the mounting profile and is used to level the structure. An additional element are spring washers that increase the durability of the connections in the face of difficult weather conditions.
The photovoltaic panels and aluminum frame must be attached to withstand strong gusts of wind. Therefore, widened nuts and hexagonal head screws with a conical collar are recommended for assembling the system. In addition, the double threads must be matched to the specific type of rafter (wood/steel).
Regardless of the type selected, fasteners for mounting photovoltaics on the roof should be characterized by maximum resistance to corrosion, abrasion, impacts and cracks, UV rays and ozone, as well as to low and high temperatures. It is worth remembering that the PV installation interferes with the structure of the building, so for its installation you should use certified products made of materials with confirmed properties.
When should double-threaded screws be installed on the roof?
Double-threaded screws are fasteners with versatile applications. Primarily, they are used for mounting photovoltaic installations, but they are also suitable for mounting other structures on roofs, e.g. snow protection. They are used where absolute strength, stability and tightness of the connection are required.
Double-threaded screws at the Onninen wholesaler
In the Onninen electrical installation wholesaler , you will find steel double-threaded screws in various sizes, intended for mounting photovoltaics on sloping and flat roofs. All products have surfaces protected against corrosion. Our regular offer also includes Allen screws, lock and hammer screws, nuts and many other fasteners. Our clients include shops, photovoltaic services and installation companies, as well as private investors planning to produce energy from the sun for their own use.