SIHGA GoFix system screws - The perfect choice of screws: A guide for the right application
SIHGA GoFix system screws
Connection details and/or the statically relevant component nodes to be solved in modern timber construction are becoming increasingly demanding and comprehensive due to the positively increasing project size and scope. In order to solve these details correctly in terms of safety, feasibility, cost-effectiveness and also sustainability with regard to an above-average service life, a certain approach and background knowledge in this area is required.
Architects, structural engineers and timber constructors can now choose from a huge range of screws available on the market in all sizes, diameters, lengths and shapes. From the material and thread form to the head and tip shape, there are virtually no limits to the choice. Wood construction screws are generally selected based on their intended use, and the location (the service class) and/or the component in which they are used is also decisive.
If you want to create a timber/timber connection where two timber components are also to be pulled together, e.g. in the case of a right-angled cross-laminated timber wall corner, a suitable partially threaded screw is selected first. Here, the shaft should have a length that is identical to the thickness of the wall to be fastened. If additional shear forces have to be absorbed in the component joint, this connection can be solved in a structurally correct and economical way using inclined fully threaded screws.
Another advantage is the ease of installation, as the fitter is installing products that he deals with on a daily basis. The same applies to beam reinforcements, beam doublings and the shear-resistant connection of several small wall or ceiling elements to form a large component.
Here, the GoFix MS II is best suited as a partially threaded screw, in combination with the GoFix X+ as an inclined fully threaded screw with cylinder head.
The service class in this case would be NKL 1 or 2, which means that a carbon steel grade with electrogalvanizing is sufficient. Please note: If such a connection were exposed to free weathering (NKL 3), stainless steel quality screws would have to be used here. The reduction factors to be applied are higher in this case.
If two timber components are fastened together where the tensile forces are decisive, for example uplifting forces from the effects of wind suction, it is also important to pay attention to the head shape of partially threaded screws. The larger the head, the greater the head pull-through resistance. So-called pan head screws are available on the market as an alternative to countersunk head screws. The GoFix MS II simplifies this and can be used for all such applications thanks to its specially stepped head shape.
If you are connecting a steel sheet to a timber component, you are well advised to use a fully threaded screw with countersunk head, e.g. GoFix S+, depending on the precise structural requirements.
The countersunk head offers the advantage that it rests firmly and positively in a predefined countersink in the sheet steel hole. When connecting steel to wood, it is also important to pay particular attention to the tightening torque. The necessary information on this can be found in the respective valid approvals assigned to the screws. Please note: Only screws with approvals should be used in statically relevant connections that remain in the structure.
There are also applications where the screw is only used to secure the position. Take timber frame construction, for example, where the head and foot sills (frames) are usually screwed to the upright transoms in the factory. The final statically relevant connection is achieved with nailed or stapled panel materials.
With the GoFix product family, suitable products are available for all relevant applications in timber construction.
GoFix MSII- Partially threaded timber construction screw with all-round head (countersunk/plate head) 4.5x30mm to 10.0x600mm (ETA-20/0558)
GoFix X+ - Fully threaded screw with cylindrical head and drill point (edge and center distances can be reduced with this screw) 6.5x120 to 10.0x600 (ETA-11/0425)
GoFix S+ - Fully threaded screw with countersunk head and drill point (edge and center distances can be reduced with this screw) 8.0x95 to 10.0x600 (ETA-11/0425)
GoFix SS - Fully threaded screw with countersunk head for maximum static loads (such as reinforcing wide-span glulam beams) 11.3x300mm to 11.3x1000mm (ETA-11/0425)
GoFix ZS - Double-threaded screw with cylinder head (for pressureless installation of two components at a distance, e.g. on-roof insulation, insulated facades) 8.0x225mm to 8.0x435mm (ETA-11/0425)
GoFix SH- Partially threaded screw with countersunk head for use in hardwood (e.g. laminated beech veneer lumber) 8.0x11mm to 8.0x240mm (ETA-20/0558)
The products GoFix MSII and GoFix X+/S+ may also be screwed in with tangential impact screwdrivers, which is easy on the wrist and therefore also on health in the long term. For applications in exposed areas, the L-GoFix MS and TeFix product groups also offer an extensive range of stainless steel products.
SIHGA support is available at any time to assist with product selection and solutions for statically demanding nodes and applications.
23 January 2024
