Module: Introduction to timber engineering design Unit: Screw connections

Date Published

10 August 2022

Document Type




Latest timber engineering standard, Eurocode 5 treats a screw as an enhanced form of a nail where axial capacities are improved. Design rules given for wood screws depend
on the screw diameter. In general, for calculating load-carrying capacity and spacing rules, screws with a diameter not exceeding 6mm are treated like nails, and larger screws like bolts.

For the calculation of bending strength, however, a reduced diameter is be used to allow for the screw thread, whereas an enhanced rope effect is applied due to their superior resistance to axial withdrawal.

Key Information

Conditions related to the sizes and limitations of wood screws and coach screws were looked at. The calculation methods

I'm interested in:

Case studies

In 2003 Meredith Bowles completed a timber frame home for his family and an office for his architect’s practice in the Fens village of Prickwillow near Ely in Cambridgeshire.

The WoodWave© Structural Roof Panel is so named because it is built completely of wood and plywood fastened together in a wave-like form to serve as a structural roof, fi nished ceiling and noisereducing panel.