# Forum Home Renovation Decking  Brackets for joists into concrete

## Pugsley

G'day
Need help big time. Building a merbou deck myself. Im a novice but up 4 a challenge
area is 10m x 5m. Problem is im building on top of an existing concrete slab.  :Confused: 
There is not enough height to use Bearers so I'm useing Joists at 450mm centres. I have no idea how to attach the joists to the concrete slab. looking for some type of bracket to hold the joist down onto the concrete.There is no height available so the joists will nearly sit on the concrete
Pugsly

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## Pulse

I use heavy gal angle brackets with one 12mm hole on each leg.  I embed 12mm threaded rod cut to length into the concrete with structural grout or chemset. The bracket is then screwed to the side of the joist with a 50mm batten screw. The height is adjusted with  with 12mm nuts on the threaded rod. Hope that make sense, 
cheers
Pulse

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## HandyDaddy

Hi Pugsley 
Take a look at 'Dans Low Deck' in this section of the forum. http://www.renovateforum.com/f196/dans-low-deck-73603/ 
He used Loxins - hope its what your looking for

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## Bloss

Don't need to over-engineer - once decking is all on it ain't gunna go anywhere so a just few brackets as described - I reckon ankascrews or equivalent work better than loxins/ dynabolts for this purpose. Be aware of managing drainage too - water needs to be able to flow away easily and as fast as it needs to.

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## infocus13

> I use heavy gal angle brackets with one 12mm hole on each leg.  I embed 12mm threaded rod cut to length into the concrete with structural grout or chemset. The bracket is then screwed to the side of the joist with a 50mm batten screw. The height is adjusted with  with 12mm nuts on the threaded rod. Hope that make sense, 
> cheers
> Pulse

  This is pretty much what I've done with my low deck (only 14cm clearance). HD gal brackets (L shaped, from bunnies) dynabolted into the concrete slab. Joists then attached to side of the brack. To be safe I ran brackets every metre for extra robustness (max span for 90x45 F7 TP is about 1400 I think). 
Cheers

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## fubar

this is what i did http://www.renovateforum.com/f196/my...ow-deck-94954/  the bearers(sleepers) just sit on the tiles and after screwing together nothing moves

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## Pugsley

Hi pulse\
Excuse my ignorance but what does Embed mean ? Love the idea of being able to adjust the height because my height to lay the joists onto the concrete ranges from abot 20mm to 60mm
Mate- Love to see a picture of the brackete your referring to. I ve lookeed all around Melb and cant find anything your referring to

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## Pugsley

> this is what i did http://www.renovateforum.com/f196/my...ow-deck-94954/  the bearers(sleepers) just sit on the tiles and after screwing together nothing moves

  Hi fubar
Great lookin deck. Is it a oil based stain- ? If so what colour
With my deck as i said i cant have bearers- just joists straight into concrete
 Novice Pugsley

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## Pugsley

> Hi Pugsley 
> Take a look at 'Dans Low Deck' in this section of the forum. http://www.renovateforum.com/f196/dans-low-deck-73603/ 
> He used Loxins - hope its what your looking for

  do u drill loxins straight thru the wood into the concrete ?
Novice pugsley

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## Pulse

I mean drill 16mm holes, remove the dust and pour in some structural grout, then stick the threaded rod in and let it set. 
The brackets are from Bunnies and come in all different sizes. They are about 5mm thick, L shaped brackets, Gal dipped with one hole on each leg of the bracket. 50x50mm or 40x40mm with 12mm holes is a good size.  
Cheers
Pulse

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## Bloss

> I mean drill 16mm holes, remove the dust and pour in some structural grout, then stick the threaded rod in and let it set.
> Cheers
> Pulse

  Nah - way over the top for an on-slab low deck like this deck - brackets are fine, but ankascrews or equivalent product http://www.ramset.com.au/fileupload/...CTION%2032.pdf are a much better choice - just a suitably sized drill hole with masonry bit in hammer drill into the slab and use a socket drive to screw the bolt home. M6 or M8 x 75 (or even 50mm in this case) and just one for each for  bracket. A lot easier to drill an 6 or 8mm hole than a 16 - and no filling or gluing either you can also attach bracket to timber then drill hole through the hole in the bracket so much easier all round. 
As I said above there is no really need for much permanent fixing or any at all to a slab in most of these low decks - the only problem is the temporary one of having the sub-floor members stay in the right place (level & square) while you join them altogether. Once the platform is built the forces are mainly down - of course one needs to look at each situation - for example if the deck is on a slab adjacent to a driveway then maybe you'd want to have something more substantial just in case a vehicle nudged the deck, but even then the deck is pretty heavy and solid so the risk is very low.

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## Pulse

Fixing costs can add up, I had the grout so it was pretty cheap for me, heights were all different, up to 150mm so meant I didn't need to buy different size brackets 
Cheers
Pulse

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## Bloss

> Fixing costs can add up, I had the grout so it was pretty cheap for me, heights were all different, up to 150mm so meant I didn't need to buy different size brackets 
> Cheers
> Pulse

  Good point - always pay to look at all the costs and the local site issues! With DIY I reckon our own labor should also be valued - not always at full rate, but while you are doing one activity it is replacing another (but so  long as you enjoy who cares . . . ).

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## Pugsley

> Nah - way over the top for an on-slab low deck like this deck - brackets are fine, but ankascrews or equivalent product http://www.ramset.com.au/fileupload/...CTION%2032.pdf are a much better choice - just a suitably sized drill hole with masonry bit in hammer drill into the slab and use a socket drive to screw the bolt home. M6 or M8 x 75 (or even 50mm in this case) and just one for each for  bracket. A lot easier to drill an 6 or 8mm hole than a 16 - and no filling or gluing either you can also attach bracket to timber then drill hole through the hole in the bracket so much easier all round. 
> As I said above there is no really need for much permanent fixing or any at all to a slab in most of these low decks - the only problem is the temporary one of having the sub-floor members stay in the right place (level & square) while you join them altogether. Once the platform is built the forces are mainly down - of course one needs to look at each situation - for example if the deck is on a slab adjacent to a driveway then maybe you'd want to have something more substantial just in case a vehicle nudged the deck, but even then the deck is pretty heavy and solid so the risk is very low.

  Old Chippy
Can u attach a photo of the brackets your referring to ?

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## Pugsley

[quote=Pugsley;826302]Old Chippy
Can u attach a photo of the brackets your referring to ? 
An honest mans pillow is his peace of mind :Biggrin:

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## Bloss

> Old Chippy
> Can u attach a photo of the brackets your referring to ?

  You'll do better if you don't start multiple new posts . . . there are all sorts of brackets - available - even Bunnings have large range.

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## Pugsley

Thanx to all for your reply's
Unfortunately my problem still exists
A) Im not ripping up the concrete
B) Im still looking 4 an adjustable bracket to screw the joists into and dynabolt  the brackets into the concrete
C) Im not digging/Cutting up the concrete for stirrips execpt in the grassed area
 No bearers will be used just joists into the concrete
Everyone says use angle brackets and 'just get them from bunnings or pryda type brackets
I cant find any at all !!!!!!!!
The joists will have a 20mm gap at the house ledger up to about 10cm at the fascia
Need some idea - getting frustrated tgher must be an idea somewhere
Puggsly :Annoyed:

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## d00biez

a picture is worth a thousand words !!! 
i think everyone was labouring under the impression you had a level surface to put your joists across (as was i). still, do what the others suggested - joist brackets all the way along the slab and then, i reckon youre gonna need 3 or 4 post/joist stirrups concreted into the ground where the height increases significantly. i dont think theres any other way ? seriously, go to bunnings and either a) walk around til you find the brackets (usually in the last isle to your left when you walk in but this may vary) or just grab one of the guys on the floor and ask him. it will take 2 secs to find them). 
just a question, is that pine in the picture and are you using that as part of your joisting ?? i certainly wouldnt recommend it. hardwood is a must.

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## Bloss

And it doesn't look like treated pine? If not just termite food . . . and dry rot fungus food . . .

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## jkirky

Easy... You just need a few brackets along the length of the joist to replace where the bearer would otherwise meet the joist. Check your span tables for the correct span between bearers... 
For the brackets I would use the earlier idea of hammering a 16mm hole with hammer drill and cementing in threaded rod, or you can buy pryda brackets for cementing posts onto concrete, and just dynabolt the bracket to the slab.  
I wouldnt buy them for this job but if you look up RoofExtenda brackets you will get the idea... These are basic L brackets on a threaded rod, just disregard the bottom half...(I wouldn't buy these coz they're 60 bucks each, but it is the best product to show you the idea... You can google it... 
You don't need hardwood but treated pine is a must. Again check your span tables... If you don't have any tell us the span and i can check it for you...

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## Pugsley

> Easy... You just need a few brackets along the length of the joist to replace where the bearer would otherwise meet the joist. Check your span tables for the correct span between bearers... 
> For the brackets I would use the earlier idea of hammering a 16mm hole with hammer drill and cementing in threaded rod, or you can buy pryda brackets for cementing posts onto concrete, and just dynabolt the bracket to the slab.  
> I wouldnt buy them for this job but if you look up RoofExtenda brackets you will get the idea... These are basic L brackets on a threaded rod, just disregard the bottom half...(I wouldn't buy these coz they're 60 bucks each, but it is the best product to show you the idea... You can google it... 
> You don't need hardwood but treated pine is a must. Again check your span tables... If you don't have any tell us the span and i can check it for you...

  Jkirky 
Length of span is 5m

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## Pugsley

Hi Guys
I purchased 10 brackets from bunnings see photos'. Not sure which one 2 use ?
My question is - if i ankascrew or dyna bolt the bracket into the concrete and attach the joist to the side of the bracket then- does that mean that the load bearing is actually by the bolts and not the bracket itself ?
Is that best practise ?
Oh yeah its treated pine- dam confused hardwood or TP everyone has a different opinion   
Pugsley (hangin out 2 start the project  :Laugh bounce spin:

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## Pulse

Use any bracket that fits, yes the bolts are taking the (small) load, yes it is best practice. What grade treated pine? H3 minimum? 
Cheers
Pulse

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## jkirky

If you use 12mm through bolts the rafters are being supported by the bolts in tension rather than the nuts on the dynabolts. This is more than adequate... Ie they don't even need to sit on the heads of the dynabolt, in fact it would be better if they didn't, but rather stay supported by 2 12mm bolts. 
Most of the brackets shown are fine, just choose one which satisfies you height requirement, ie isn't too tall, or is actually tall enough. It may actually require you to mix a few different types of brackets to establish your height...

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## d00biez

[quote=jkirky;827645] 
You don't need hardwood but treated pine is a must. quote] 
im not arguing with you but my thoughts are that hardwood is the best solution for longevity. its hard wearing and copes with the tough aussie elements. pine on the other hand will warp with sun and rain over time, sometimes very quickly. 
just my two cents!

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## Pugsley

Using F7 TP

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## Pugsley

> Using F7 TP

  Hi 
Im using suspended joist saddles. Any tips ?
 joists are 90mm x 45mm

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## Stan 101

Any of the brackets would do the job. I i'd prefer to use 12G 25mm Timberfixx screws for the bracket  to joist connection. It spreads the load and minimises the chance of splitting the joist as is potentionally possibly with a 90mm timber with an M12 bolt. 
If however you decide to use a bolt, I'd get some hammer on Pryda nailon nail plates and hammer them on both sides of the hole you drill. That will minimise the chance of split. The mailopn plates can be minimum size. 
Cheers,

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## Pugsley

Hi Guys
Have decided to sit joists 90 x 45 onto Bricks supported by about 300mm depth of concrete. Question is what is the best method to secure the joists onto the Bricks ?

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