Using metal fasteners on wood: what to watch out for

Using metal fasteners on wood

From self-tapping to bugle battens to socket head screws, hex bolts and wood screws, screws are one of the most reliable fasteners used on wood. Screws transfer weight loads reliably, seldom bend and typically come with a coating designed not to damage the substance they are being driven into.

Using metal fasteners on woodThe single biggest advantage of screws is they can easily be removed later if it’s necessary to put in larger ones, replace faulty screws, or move them to a different place. They’re also often available in a range of colours to match the wood they’re being used on.

‘Self-drilling screws’ (also known as self-driving) are a useful trend in fasteners, meaning they come with a sharpened head which cuts snugly into the wood. These are the norm when laying boards on a deck. They’re thin and surgical and have a large surface contact area, and although they typically cost more than nails, screws are extremely useful.

Corrosion: what to watch out for

However, when driving metal into wood, there is a risk of allowing corrosion in. This is particularly worrisome when dealing with top-heavy structures, especially elevated decks. If corrosion sets in around any of the fasteners used to hold a deck together, it can weaken one area of the deck, leading the next area becoming unsupported, until instability spreads.
Moisture getting trapped in the wood is the biggest issue here, so it’s essential, if you are driving steel fasteners into wood, to understand how corrosion works.

If the deck, fence, or framing timber has less than 20% moisture content, it’s considered very dry. There will be minimal corrosion. However, any moisture content over 20% is worrying, whether the wood is treated or not.
Hot dipped galvanised or stainless steel fasteners are ideal to go into wood which has a copper / salt -based preservatives; electroplated galvanised fasteners are not bad either.

How, stainless steel fittings are required for treated timber used near sea water, as salt is particularly corrosive.

Another metal-wood issue to watch out for is preserved wood with copper-based preservatives, which should not be in close proximity to aluminium siding or aluminium door and window frames (allow 6mm of space between the treated wood and the aluminium products.)

Sound like a headache? It’s all stuff known by heart by the Renovation Warehouse team, who bring decades of experience. The range of screws, nails and fittings at Renovation Warehouse is modest, but the staff expertise is not. Even if our staff don’t have it in store, they’ll help you locate the exact fitting you’re after for your building project.

If you have a restoration project or are renovating your house, then come and browse through the comprehensive selection of fixtures and fittings at Northland recycled building materials specialist Renovation Warehouse, located at 28 Kioreroa Road, Port Whangarei.

Or simply contact the team at Renovation Warehouse to discuss your requirements and we will match the fixtures and fittings to your renovation project. We can even match up like with like for common items from different decades of building, depending on our current stocks.

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