# Forum Home Renovation Decking  low deck joists on concrete options

## DIYwannabe

GDay everyone, massive fan of this site and have used it heaps  so thanks to all for the input. I have a few questions regarding a small low deck I am building onto and existing slab in a courtyard. I have built a few decks before and go for quality over cheap and easy  but I dont like to ridiculously over engineer things either!! 
Q1.1) Which option is better: Joist bolted directly through joist into concrete or L brackets? 
1.2) Which is easier to use?
1.3) Which is better quality? 
Q2.1) Also in terms of spacers for air-flow/drainage which is better: Wedge it or Horseshoe spacers?
2.2) Which is easier to use?
2.3) Which is better quality? 
Q: 3.1 Furthermore, in terms of fastening to the concrete which is better: Dynabolts or AnkaScrews?
3.2) Which is easier to use?
3.3) Which is better quality?
And lastly should these fasteners be zinc plated, galvanised, or stainless steel?  
Cheers 
DIYWannabe

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## oohsam

Here's what I'd do.  
1. Either put a dynabolt in the concrete, drill through the joist and bolt down with the bolt, angle grind the thread off. (bore out joist so the bolt fits into the hole or you will have some issues with ur deckboards! yikes!  
2. Horseshoe or wedge is fine. They are pretty much the same thing but i like the wedgies better. I used them on my deck over concrete. Make sure you dont rest the joist on the concrete for water run off etc.  
3. Anka screws are probably easier, but dynabolts will do the job, its not pulling out, like a gate on a brick wall for example so either is fine.  
I'd go for Galvanized all day every day, since you wont see it, but def use stainless for the screws to hold down the deck boards. a bit more classy.  
Cheers.

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## oohsam

Here is a great reference guide to what you are doing and how you should do it.  
This is very very over engineered in my opinon though but great none the less.   http://www.renovateforum.com/f196/dans-low-deck-73603/

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## DIYwannabe

Thanks heaps for the advice. 
One other questions: when bolting down the joist, is it best to do it close to the wedge (within 30-40mm) or further away?  
DIYwannabe

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## Bloss

> Thanks heaps for the advice. 
> One other questions: when bolting down the joist, is it best to do it close to the wedge (within 30-40mm) or further away?  
> DIYwannabe

  Close to but not through the wedge or the timbers will bend as you tighten down.

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## DIYwannabe

I have noticed on other posts that people also mention gluing the wedges (with an heavy duty exterior glue) to stop them from dislodging over time.  
I am keen to do this also but when it comes to doing this gluing, is the glue applied just to stick the wedgies together and join them with the joist; or 
is the glue applied all over, to the concrete underneath, the wedgies and the joist -to join everything together? 
And is this gluing done before dyna bolting or after? I assume after would be too difficult but then I am just concerned that applying the glue before dyna bolting will add additional height to the final level of the joist and put it out?  
Any thoughts/suggestions? 
Diywannabe

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## terryB

Hi wannabe, 
The low joist thing had me muddled for a while but in the end just followed UteMad seems the right thing to do around here. :2thumbsup:  
I chose to use galvanised angle brackets instead of boring through the joists. Simply because I had to use really thin joists 70x45 and I had a sloping base to work off. It was easy in my case because the one end of the joist was already fastened so all I had to do was then get it level and square and then fasten the bracket to the floor and the joist. I used gal ankascrews and hot dipped gal brackets from Bunnies. 
I just rough guessed intervals for the support mid joist dumped a big dollop of glue on the concrete bit of glue between each horseshoe and then tapped them in place with a hammer so they were nice and snug. 
More info on that here  
Not much help to you but I can say for the month that those joists lay exposed and everyone walked on them and did whatever they liked they did not budge a millimeter. It rained it baked we even had a few chilly nights and it all stayed straight and true so pretty sure it will be up for a while yet. 
I would not dwell on it too much, just get on with it, you can spend months if not years paining over the detail of the build with all the info in this forum but at the end of the day you are going to build it to your desires, skill, tools and budget. 
Good luck
Terry

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## Bloss

I wouldn't bother with glue. Messy and if the deck is put together well not needed. Wedges are useful as they can be tapped tighter if there is any movement or shrinkage. But only if they are accessible of course!

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## DIYwannabe

Thanks terryB for the advice. Your right - enough planning. Time to get cracking. 
Thanks to all for the help - will post some picks when I am done. 
Cheers 
diywannabe

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