What decking posts to use?

[canberraben]

Hi there 

I’m building a 2x4m deck off the back of a pool. The deck will be just under 1m in height so it doesn’t require a BA or DA under ACT planning rules. 

My question is about deck posts. There are two options to chose from: 

- the 100x100 rough sawn posts

- or these Kaituna posts

In the Bunnings ‘how to build a deck’ video they are clearly using the 100x100 rough sawn posts, cemented into post holes. 

Are these posts suitable to use at 1500mm spacing for 190x45 bearers? Or do I need to buy the more expensive posts because they are “structural”? 

Thanks! 

[Jason]

Hi @canberraben,

Welcome to the Bunnings Workshop community. 

Sounds like an exciting project! We'll be keen to see how it progresses.

Our apologies, but a couple of our resident Bunnings D.I.Y. experts are taking a well-earned break at the moment, so there might be a bit of a delay before one of the team can get back to you. 

Let me tag a few experienced community members who might be able to share their thoughts in the meantime: @Dave-1, @TedBear, @Jewelleryrescue.

Jason

[Dave-1]

Afternoon @canberraben 

Cheering at constructing a deck that backs off the pool So much fun!

I prefer the 100 * 100 rough sawn posts, mostly because they are 100 * 100 and therefore make it easy to figure things out such as notching and joing timber together plus I dont need to worry about the plane they are in as its a square

I also prefer the deck sit on stirrups with an air space of 10mm between the post and the stirrup to lesson the chance for rot to start.

Here is my deck project in case you want to wander through

Pool deck stage 1 

Pool deck stage 2 

The 90 * 90mm are structual tho cant see the others as when I search the link is broken and also when I search google it comes back with the broken link as well.

I would choose structual timber over non structual every time, even wehn not needed. It saves headaches and also for that little bit higher price it will last longer.

Dave

[MitchellMc]

Hi @canberraben,

Our 100 x 100mm 3.0m H4 Treated Pine Posts are not structurally rated and only suitable for landscaping purposes; you can't use them for posts on a deck. The 90 x 90mm 3.0m Post F7 H4 Treated Pine Premium KD are structurally rated, and suitable for your deck. 

In the Bunnings How To guide, they are actually using 100 x 100 rough-sawn Cypress posts, which are structurally rated but only available in some locations. 

Regardless, though, the span between posts is determined by the calibre of your bearers. A spacing of 1500mm would be nicely within the span of 190 x 45mm.

Please let me know if you have any questions.

Mitchell