In modern timber construction, wooden beams and joints are screwed together with wood screws or nailed flat with metal connectors.
Notches, overlaps, and other traditional timber joints are real eye-catchers and embody the craftsmanship of carpenters – but from today’s technical point of view they have the following disadvantages:
The timber cross-section is weakened (part of the load-bearing beam is removed).
The weakening is often exactly at the critical, particularly stressed points.
The flat end-grain sections and joints are particularly critical for water accumulation.
As beautiful as the old joints are, from a technical point of view we have better means at our disposal nowadays – instead of hand-forged nails, there are now special wood screws for every type of joint:
- Exterior / Exposed to weather:
- Stainless steel screws ø 5–6 mm (max. 120 mm long, otherwise they become too brittle and tear off!).
- For all longer screws, use galvanized screws ø 6–10 mm (correspondingly thick and long galvanized screws!)
- Interior / walls / dry constructions:
You can find more detailed information on wood screws and their range of application at the respective manufacturer, e.g. “Spax”.
In the following video from “Befestigungsfuchs” you can see how long the wood screws should be: https://www.youtube.com/watch?v=N5OlwrK6ILs