How to build a low-level deck?

[PscottDIY]

Hi Team,

planning on building a deck under our new patio approx. dimensions;

~8200L

~4700W ( can be flexible on this to suit a standard board length to avoid cuts ) 

~150/200H 

ideally wide Boards running out to the grass. 

Most of it can be supported by an existing concrete patio, with I assume some footings on the outer side closest to the lawn.  

Can you please help me with how so set out the frame / bearers / joists  footings etc ? what sizes to use etc ?

Cheers 

[PscottDIY]

Great , one more - how far can my joists hang over a bearer , my minimum bearer spacing is 1m , but some closer to 850 mm , I had to mix them up due to existing patio posts 

[MitchellMc]

When you say "hang over a bearer", @PscottDIY, are you referencing the maximum distance the joist can span between bearers? For 90 x 45mm, I like to say around 1000mm. I believe it can technically span further up to around 1500mm, but the deck will become quite bouncy at that length.

Mitchell

[PscottDIY]

[PscottDIY]

@MitchellMc my maximum bearer centre is 1m so I’m all good on that front ( actually have 9 bearers now ) ; question I think is how far can the joist’s cantilever over a bearer , see pic 

[MitchellMc]

It's a ratio of their overall length @PscottDIY; if it's just 30cm or so, that should be fine.

Mitchell

[PscottDIY]

Gday gents @MitchellMc @EricL couple more questions;

- what screws do you recommend for noggins ? ( ideally ones I don’t have to pre-drill ?

- also what spacing do you recommend for my 140mm boards ? 

[MitchellMc]

Hi @PscottDIY,

You should be able to get away with using Zenith 8 - 10 x 100mm Treated Pine Countersunk Head Screws and not pre-drilling. However, you might find they split the end of the noggins and if so you'll need to pre-drill.

For a low-level deck, it's best to provide a decent gap between boards of at least 5mm.

Mitchell

[PscottDIY]

After some holds up with work, travel and holidays sharing my deck pics. Bar the final oiling and a few trim pieces very happy with the overall result. Thanks for your help and advice team 👍 

[EricL]

Hello @PscottDIY 

Thank you so much for posting your finished project, it looks magnificent. It looks so inviting and relaxing. Did you by any chance take pictures of the frame while you were assembling it? Did you eventually use the 90x45 timber framing? What footings did you utilize?

Again, thank you so much for sharing such a wonderful project.

Eric

[PscottDIY]

 Cheers Eric,

 bearers were 140x45 , joists 90x45 , as the concrete underneath had quite a fall and was also smaller than the finished deck size I used a combination of footings / fixings. Galvanized angle brackets at the lowest points and then Buzon adjustable pedestals ( a great sturdy strong rated product- Bunnings should stock them , also concrete footings with stirrups at the end of the bearers. The frame is really sturdy and I’m very happy with it 👍