top of page

Fasten The Full Roof Structure Without Damaging Any Truss Connections Or Materials

Structural screws are stronger than traditional fasteners, with the ability to make longer-lasting connections. The labour difference with these screws is huge; you can just zip them in with a handheld drill without the frustration of pilot holes or ratcheting. With structural timber screws you'll finish the job in half the time and rest easy knowing that the connection will hold.

These fasteners might look less "robust" than others but they are actually made from stronger, heat-treated steel, which makes them the perfect one-to-one replacement for the thicker screws you may be accustomed to.


Over the past few years, the structural timber screw has proven to be the perfect fastener for various applications including:

· Purlin connections for sheeted roofs in high wind force areas.

· Purlins to rafter fixing on exposed trusses.

· Multiplying girder and bracing connections

· On-site remedial work.

· Purlin connections with insulation material to secure 100% effectiveness.

· Connections in roof structures, etc.

Advantage for the professionals

Architects and engineers can overcome the challenge with exposed trusses, with tried and tested design values to achieve the ultimate grand design.

A big advantage for the contractor is the time saving component with fixtures and the fact that you can loosen the connection without damaging the material if any mistakes are made. No pilot hole needs to be drilled which further serves to improve flexibility and ease of use.

The secret behind the structural timber screw

The screw is an engineered product manufactured from high carbon steel with a deep screw thread which has the following characteristics: - High tensile, shear, and torsion strength - Serrated thread to cut the timber fibers and prevent timber splitting - 1.5mm thread depth to secure higher pull-out value - Serrated thread to reduce screw gun torque - Treated to the required corrosion category

Performance comparison

Let’s compare the different fasteners in lateral bearing force, perpendicular to the timber grain:

In Europe, America, and Australia, the structural timber screw is the norm for connecting timber members.

Test results

Prof W M G Burdzik (Pretoria University / Purlin to rafter connection) -

"The single flat-head screw is as strong as a double nailed hurricane clip."

Prof J A Wium (Stellenbosch University Institute for Integrated Technology / Isoboard connection test series) -

"It was also found that screw connections have a higher stiffness than conventional purlin clip."

Fig 1 – Biligom 50 x 50 and SAP 50 x 76 purlin connection with the correct insulation membrane placement to secure thermal resistance R value (m² K/W)

Fig 2 – IsoBoard connection for board over rafter connection on exposed trusses.

Fig 3 – The perfect connection for lateral shear resistance and aesthetic appeal

Simpson Strong Tie & Spax dealer

Wolf Fasteners & Accessories is proud to supply only the highest quality, laboratory- tested products to the truss and timber industry.

610 views0 comments

Recent Posts

See All


bottom of page