Building a deck on concrete - What to do with joist not on concrete?

[eliot]

Planning out a 3.5x6m deck and was hoping to keep it as simple as possible to do it myself.

Originally I intented to attach the joists directly to the concrete with the below adjustable feet. Running them from the brick outwards 3.5m to have the hardwood decking run the 6m length of the deck. I would then nog the joists together for extra lateral stability. The height of the deck would be 220mm off the concrete to line up with the door frame which works perfectly with 90mm joists and the 150mm kleva klips.

The problem is I am installing an awning window with a servery on the left hand side and really want the deck to run a little past it so I can sit stools along it so the final joist will not be supported by the concrete slab. The dilemma this creates is now I have to go to all the hassle of mixing concrete for just one joist.

My current thinking is use a joist hanger to bolt one end of the joist directly to the brick. This will still be below the top of the slab so I figure this will be a lot more reinforced than a regular veneer brick. At the other end I was thinking I would dig a hole half a metre, put a few of those 50mm thick concrete pavers you see in there and screw a stirrup like below to them. This would allow me some adjustability in height to get it level as I could put shims in before I bolt it through the joist. I would just have to make sure I get the stirrup square. I would then do something similar but with a 300mm stirrup at two more support points along that joist. That joist would also be nogged to the next one which would be bolted to the concrete.

Am I mad for trying to attach the joist to the brick? Should I just bite the bullet and bury a post at both ends and pour concrete?   

Is there a better way I am missing?

https://www.bunnings.com.au/pryda-post-anchor-full-stirrup-600-x-90mm-m12_p1120027

https://klevaklip.com.au/Joist-Supports

https://www.bunnings.com.au/pryda-joist-hanger-to-suit-45-x-90mm_p0294207

https://www.bunnings.com.au/90-x-45mm-outdoor-framing-mgp10-h3-treated-pine-2-4m_p8032172

Awning window with servery going on the left

[MitchellMc]

Welcome to the Bunnings Workshop community @eliot. It's fabulous to have you join us, and many thanks for your question about constructing a deck.

I'd just shift those pavers and whack pedestal feet on them. They don't need to be fixed to the pavers, and if you connect that last joist to the second last, that will take care of any twisting. If you check out How to build a deck, you'll see the entire deck was created with the pedestal feet.

Also, have a think about whether you'll be picture framing the deck. If so, on the ends, you'll need to run a spaced double joist. One joist is to fix the perpendicular picture frame, and the other is to nail off the ends of your decking. With this setup, you can place the pedestal foot on the inner joist so it can't be seen from the outside. You can then run another board around the edge of the deck to finish it off and cover up the joists. You'll see how to do this in the above guide.

Please let me know if you have any questions.

Mitchell
 

[eliot]

Thanks for the words of encouragement!

I was a bit concerned if they were just sitting on the pavers they might sink slightly over time and cause the end of the deck to sag.

Your way is much simpler though, I'll give that a go.

I do plan to picture frame it and mitre the 2 outside corners. I figured I would connect two joists parallel with a piece of pine sandwiched in between at each end and that would allow for a 130mm wide outside frame.

Also I wasnt going to worry about a frame along the brick side of the deck. I am going to have to have a 50mm rip in the little step the door frame is sitting in. Originally it had sloped bricks here which I removed.

[EricL]

Hello @eliot 

That sounds like a good plan, I suggest drawing your decking frame plan on paper first. This will give you a good idea of how the decking frame will come together. Plus, it will allow you to quantify the materials you'll need.  That mitred corner of the deck sounds interesting; I look forward to seeing it.  

If you need further assistance, please let us know.

Eric