Decking Screws

[deansewell]

Hi,

Just a very quick question – would No8 x 2 1/4 stainless steel decking screws be OK for fixing 19mm Balau deck boards?

I plan to use two screws for every joist spaced at 400mm. Sound OK?

Dean

 

[shenks]

Hmmm... whilst I have done a few decking jobs I am by no means an expert!

However, by comparison I have used 70mm Timco Dextra yellow passivated screws when using either a 25mm or 32mm decking board. This means I am 50/43mm in the frame/joists (allowing for 5mm countersink) which is plenty of grab. You may be a bit short with 2 1/4 (55mm if my maths is correct).

Also since you are only using 19mm decking board then 400mm centres may lead to some springiness so I would reduce to 350mm centres and/or use quite a few noggins too.

Two screws per board width on every joist is fine - just don't go too close to the edge.


Somebody else may be able to give more detail but I hope this helps.

 

[iaith]

stainless steel screws will always out live the timber you're using, 'tho I've never used balau. personally I use a simular size screw but cheaper coated version. the question is do you pilot and countersink the boards? I drive the screw straight through the board and into the joist to avoid cutting the grain and creating an end grain for water to get into. but not every one agrees with this.

good luck

 

[beem]

we have just done probably over 100 sq m of balau decking and we used 65mm screws. I think that's about 2 1/2? we used the green coated ones as the whole lot was stained down to almost black and those screws didn't stand out like the ss ones would have. So far no pull outs but the decking we used was a mix of 19mm and 28mm and the boards have shrunk alot. they were all spaced at 5mm but now alot of the gaps are 15mm. But that's wood and it still looks pretty impressive. We piloted and countersunk the board and not really the frame if that helps.

B.

 

[deansewell]

Thanks for your replies guys. That is significant shrinkage, 5mm to 15mm. Is this typical? Thats like 5-10% Do you get the same % shrinkage lengthwise?