Low level deck

[dazezy]

 

 Hi everyone. New to the website. Looking to build a deck at the girlfriends house. Any advice on ticking all the boxes would be really appreciated.

First issue I face is the lack of clearance under the deck, is this something I can resolve using H4 timber. I’ll will have to dig out and remove some sand. Is there a minimum gap that is required underneath the frame?
This is what I’ve got planned so far.

Size of deck 4.8x2.6m
Bearers 140x45mm @ 1300mm centres (should I go double bearers?)
Flush joists 140x45mm @ 400mm centres using joist hangers.
Thinking of using stirrups though unsure on the spacing.
At this stage thinking of building and installing the frame in two modular section of 2300x1400mm.

Pretty new on the DIY game so any advice would be great.
Cheers

Community manager's note: Check out How to build a low-level deck for expert advice.

[Jason]

Hi @dazezy,

At the bottom of this page under You might also like.... you will notice that low level decks are a common challenge for Workshop members. I would encourage you to check out the other discussions as they contain plenty of helpful advice. 

Let me also tag some very helpful members who might like to kick off the discussion for you: @Adam_W, @Brad and @ProjectPete.

Great to see you make your first post on the site after being a member for a while. We are looking forward to seeing many more and seeing your decking project come to fruition. 

Jason

[ProjectPete]

Always love a good deck @dazezy 

• You should have minimum 200mm but ideally 250mm clearance for H3 timber.
• You can use H4 to overcome the clearance issue but it can be harder to work with. I tend to use it for borders where I can't get the right clearance due to adjoining features (grass, pool etc) then H3 for the remaining frame.
• 140x45 for bearers is ideal although the 1300mm centres is overkill, you can easily push that to 1500mm.
• 120x45 is more than enough for joists and 400-450mm centres depending on the decking material you're using.
• I just concrete posts into the ground using H4 100x100mm posts rather than stirrups but totally up to you. I'd do 4 posts (1600mm spacing) for the 4.8m side and 3 posts (1300mm spacing) on your 2.6m side. 1800mm spacing is fine for 140x45mm bearers but the suggested spacing keeps things even without exceeding 1800mm.

What sort of decking are you finishing it with?

Where are you located?

[dazezy]

Hey Pete, appreciate your quick reply and helpful advice.  I live in Perth and at this stage going for a composite board, prob Ekodeck from Bunnings.

* Will 120x45 bearers still be okay for this board?

* Thats a lot of dirt to remove, i think just over 3 cubes.  Do you think H4 would be worth it. Also what do you mean about H4 being harder to work with?

* H4 posts sounds like a good option. What diameter/depth would you suggest for the hole?

Thanks again for you help

Darren

[ProjectPete]

I'm in Perth too - will make it easier to help.  Also means you can benefit from my trade pricing for materials including the decking.

140x45 for bearers, 120x45 for joists.

H4 often isn't as straight so makes it harder to work with over an entire deck frame.

You want the hole to be 300x300x350 with 300mm of the H4 post to be in the hole, leaving  about 50mm space at bottom of hole so the concrete sets under and around the post. Make sense?

[ProjectPete]

I also suggest having your finished height of deck higher than the existing paving.

It gives it more of a feature and creates dimension/levels in the space. Cheeky side benefit - also reduces how much sand you need to remove for the clearance

[dazezy]

Excellent thanks. 
Understand the last part in regards to the posts 👍🏽
Starting to tick a few boxes. 
In regards to fasteners Pete, what would you use for the frame and connecting the posts?

[ProjectPete]

You can go with M12 cuphead bolts or the easier cost effective and still strong option is 125mm 14g batten screws.

Make sure all fasteners are Class 3 Galv or Stainless Steel. Zinc coated will corrode in H3/H4 pine.

[ProjectPete]

If you join the bearers to posts with a rebate (most solid join) then 100mm batten screws are obviously sufficient.

[ProjectPete]

This is the rebate join I mentioned https://www.workshop.com.au/t5/Outdoor/Decking-frame-bearer-stump-rebate/m-p/33659#M5521