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Decking on concrete slab

Bunnings Team Member
Bunnings Team Member

Re: Mixed Decking (Steps & Deck)



19mm decking is adequate and I can't see any significant advantages of stepping up to 22mm.


The larger the gauge of decking screw the more holding force it has. The compromise is that the heads also get larger and more noticeable. 12 gauge stainless steel decking screws would be more than adequate for your deck. 50mm would be fine but if you did decide to use 22mm decking I would suggest 65mm instead.


Since your joists are 90mm wide you'll need to heavily countersink a 65mm screw to get much penetration into the joists/noggins. For joining the frame to the joists I would recommend countersinking Buildex 14-10 x 100mm Climacoat Bugle Head Batten Timber Screws - 25 Pack 50mm into the frame and two screws per join. For joining the noggins to the joists you could use Buildex 14-10 x 75mm Climacoat Bugle Head Batten Timber Screws - 25 Pack countersunk 50mm in the joist and two screws per join.




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