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I have an alfresco area which I'd like to deck. The joists (Green lines) will most probably fix straight into the concrete and ideally, I'd like to go 1500mm beyond the concrete (Red line). I have a storm water pipe (White line) about 800mm out from the concrete. 800mm out from the concrete, the ground is at its lowest point, which is about 200mm lower than the alfresco. With regards to the footings and bearers, what are my options?
Community manager's note: Check out How to build a low-level deck for expert advice.
To get the last joist in, I'll need to use a Pryda Framing Bracket:
https://www.bunnings.com.au/pryda-joist-hanger-to-suit-45-x-120mm_p0294195
From the downpipe, to the edge of the pillar, I have about 105mm to play with:
What is my best option for fixing the bracket to the brick (considering how close it will be to the edge) without cracking the brick? 10G 65mm Screw Bolt? Pryda themselves recommend 12G.
Otherwise, my next best option is to fix something to the slab and fix the joist to that...
EDIT: Come to think of it, a framing bracket fixed to the brick (which is hollow) probably might not be the best. After a bit of reading, I think a 90x90 H4 treated post that is fixed to the slab using 2 (maybe 3) chemset anchors would solve my problem.
EDIT2: I've dug away the soil and exposed slab which gives me 200mm of concrete to work with. The downpipe does actually deviate towards the stormwater pipe, but this is at about 210 to 220mm down. So, I think what I'll do is fix a 90 x 90mm H4 post into the concrete with 2 fixings. The holes will be about 65mm from the edge of the slab, so I think a 220mm galvanized threaded rod (M12, maybe M16 of which around 110mm will be in the slab) chemset into the concrete will be more than sufficient to hold the joist up.
Hi @IronStan001
Using a 90x90 H4 post in combination with Chemset sounds like a better idea. Drilling several holes into a single brick will definitely weaken it. Plus, there is the possibility that with that many holes the brick will crack.
Eric
Hi @IronStan001
I think 3 x M12 should be sufficient to hold the post in place. It's better to spread the load rather than concentrating it in two spots only.
Eric
OK, so with respect to fixing the joist to the post, how would I best acheive that? Consider that I plan on finishing the deck with a fascia board (140x19mm). The easiest thing would be to fix the post and joist flush, then I can fix the fascia to the joist as needed. Could I use a joist strap (or similar) the right side (red arrow) of the joist to fix it to the post and maybe pop a couple of nails/screws from the joist to the post (purple arrow)?
Hi @IronStan001
That's an excellent idea using the joist strap in combination with screws. It should be strong enough to hold the joist in place. I would also suggest placing a nogging near this spot to add extra support to the joist.
If you need further assistance, please let us know.
Eric
Hi @IronStan001
A couple of mid-sized stones and some gravel should be enough to provide drainage for the footing. Place your builder's line for the footing and test for height. When you are confident that the footing is at the correct height you can then put the concrete in.
I suggest mixing the concrete in a wheelbarrow to get the consistency right before tipping it into the hole. In this manner you'll know that there are no unmixed portions of your footing.
If you need further assistance, please let us know.
Eric
For the span from the slab to the bearer, considering I'm using 50x50x100 brackets, should I instead use 65x65x130 so I can hopefully use 2 bolts rather than 1?
