Gerber connectors & cleats

The longitudinal connection of centre or ridge purlins is particularly demanding, especially when this is not done directly on a support. In order to improve the statics, the joint can be positioned in the area between two supports so that the load and torque of the purlin is favourably influenced. This connection is called a hinge joint. And in order to ensure that this is perfectly effective, we offer an innovative wood connector for this special case: the SXGER two-part hinge connector.


Our SXKN purlin cleat is just as innovative and offers an extremely easy-to-install securing system for all coupling purlins that rest on inclined roof trusses, for example in long-span trusses. The purlin cleat prevents the purlins from slipping and tipping over. Purlin cleats also stop rafters from twisting on the support.

2 Products

2-part Gerber connector SXGER
Gerber connector
  • Material: Steel
  • Surface: Zinc-plated
Cleat SXKN
Purlin cleat
  • Material: Steel
  • Surface: Zinc-plated

The SPAX Gerber Connectors and Knaggen

What are the challenges for fastening?


The basic prerequisite for a good tanner impact is the transmission of shear force between the two purlins. To ensure this, the connector should be very large in order to be able to use as many nail or screw holes as possible. Since shearing off the fasteners is also the biggest challenge here, they should have a corresponding load-bearing capacity.
In the case of the knagge, it is above all the forces caused by tilting that are exerted by the mostly large-dimensional coupling purlins. Knaggen are therefore often designed as an isosceles triangle to absorb these forces.

What solutions does SPAX offer?


Our tanner connector SXGER is two-piece, so you always have the right connector for every wood width. There are five heights to choose from for different wood cross-sections. Furthermore, it offers a sufficiently large number of holes (2 x 23 to 2 x 35 pieces) to safely transmit the lateral forces. The small folding on the underside facilitates installation. Due to the large shear forces that occur, only our SPAX grooved nails and SPAX wood connector screws can be considered as fasteners.
A particularly solid wooden connector is our Knagge SXKN. The triangular shape in several axes is suitable for absorbing even high tilting torques and dissipating them into the wood below. We also offer five different sizes and widths for the various applications.

We help with the choice of screws

Find the right screw for your project – with our screw consultant

For every challenge, SPAX has a screw that is up to it:
Find exactly the fastener your project needs with our screw consultant.
With a few clicks you can find the right screw for your application.

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