Screwing is an increasingly popular alternative to the traditional method of joining wood in buildings through nailing. Although nails are still commonly used, screws are now more frequently employed in assembling panels and in load-bearing structures. Building brackets are another crucial component combined with both nails and screws to facilitate the transfer of forces.
For outdoor use, it is essential to use rust-resistant or stainless-steel screws and building brackets to ensure long-lasting durability.
When considering using screws instead of nails, there are several factors to take into account:
- Will the screw be exposed to moisture?
- What is the underlying material?
- What materials need to be fastened together?
- Is the surface intended to be spackled or painted?
- Is there a risk of cracking?
Stainless steel panel screws are suitable for particularly exposed areas and for attaching exterior panels made of hardwood, unpainted wood surfaces, iron vitriol-treated, or impregnated wood. Pre-drilling may be necessary when screwing in groups, near end grain, and when working with hard wood species.
To avoid galvanic corrosion, copper and aluminum plate brackets should be fastened with screws or nails of the same material or use stainless-steel variants. For outdoor applications, hot-dip galvanized screws and stainless-steel screws are recommended in areas with particularly high stress.
Note that hot-dip galvanization with a coating equal to or greater than 50 μm (micrometers) corresponds to corrosivity class C4. Stainless-steel screws of grade A2 match corrosivity class C4, while grade A4 matches corrosivity class C5.