# Forum Home Renovation Sub Flooring  Timber anchors

## Chain

Hi
I'm  looking for a bit of advice concerning a particular type of post anchor. 
I have just about got everything together to start on a raised storage area in the shed. Even bought a router for doing checks to house the bearers. It will be 3x3 metres & about 1.6 metres high from the existing concrete slab level to the underside of the joists. It will actually be a freestanding knee braced deck under which a car will be parked.
The posts (4 at 100x100mm) & joists(100x50mm) will be used hardwood & the double bearers durawood (240 x45mm). The deck will be 15mm ply. The joist spacing will be about 30-35mm. 
I expect the weight of the deck will be about 500 kilograms unloaded. About 125 kg per post. I expect the deck to take a load of say 500 kg so that will put another load of 125 kg per post making a total constant load per post of 250 kg. 
I had intend to anchor the post to the concrete floor using Pryda Bolt Down Post Anchors. ( their web site is www.pryda.com.au) Apparently they can be adjusted a certain amount after the bolt hole has been drilled into the concrete. 
I looked at them in Bunnings & am now a bit uncertain as to whether they would be up to the job of supporting the weight. (2mm stirrup/ 3mm base) It is almost certain I will not be able to get the base of the post to  sit squarely on the raised anchor bracket. 
I am sure I will find they will do the job fine but is there anyone out there who has used them & can confirm they will be  Ok for my small project. 
Thanks

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## Bloss

Why would you use post anchors at all? The posts can sit directly on the floor and just be attached using suitable angle brackets ankascrewed or dynabolted to the floor and bolted to the posts. The forces are down not sideway, but of course you need to make sure that a tap with that car or something less solid does not kick the posts away - but that would take some force especially if you really have 500kg or a tonne up there empty and much more when loaded.  :2thumbsup:

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## Chain

My original intention was to sit the posts directly onto the concrete floor & use angle brackets to secure the posts to the floor by way of bolts & dynabolts.
Then I reckoned if i'm going to be dynabolting the post to the floor in any case, why not raise the posts off the floor using  pyrda post anchors so that I can hose the shed out & keep the base of the posts fairly dry. In addition, I expect to be doing the job pretty much by myself without an offsider. I think it will come in handy to have the posts semi anchored at their base & in their approx final position while I play around up top getting things reasonably vertical & in place before drilling the holes & attaching the twin bearers to the posts.
May still do away with the pyrda anchors, but what do you think of there suitability, strength wise,  for my job.
thanks

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## Bloss

Yes not a bad thought if you are hosing etc although that would add moisture to the area that would reduce the life of any gal product. In any case the Pryda brackets are fine for the type of use you suggest. 
But even using dynabolts or ankascrews and angle brackets you can easily use spacers to give a 10mm gap without any problem. Even flush on to concrete I wouldn't be too concerned about hosing out etc. If I were intending to put water on the floor area in that way (I wouldn't be wanting to do that too often or at all in an enclosed garage). I'd use some suitable silicone under the brackets and posts as I installed just to add a bit more resistance to water ingress.  :2thumbsup:

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## UteMad

I did a storage floor in a garage of ours .. same idea car goes half under.. just put the posts down the walls and sat them on a 10mm plastic packer thru in a few dyna bolts for bracing of the post and built the rest like any other raised deck and put yellow tongue for floor.. Got plenty up there so used 6 x 2 for joists and a 10 x 2 from memory for front bearer .. over kill but it was all in stock .. posts i had were 5x5 also overkill 
cheers utemad

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## Chain

Thanks Bloss. Thanks Utemad.
I'll give the pryda brackets a miss & put the posts on a plastic packers.
Hope someone at Bunnings knows what they are because I don't think I've ever seen one.

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## UteMad

we call them horse shoe packers .. photo below shows one and the end you cant see joins the 2 bits to make a "u" shape   they are usually 60mm long 40mm wide with a 10mm slot up the middle to allow for a fixing.. they come in different thickness usually 1.5mm 3mm 5mm 10mm    
utemad

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## Chain

Thanks again Utemad.
One final question. I've been tracking some used oregan beams on ebay. Bidding is just about closed & the price seems pretty good. (http://cgi.ebay.com.au/Recycled-timb...s-Oregon-beams-) I thinking of using twin 200x50 oregan beams in place of the twin 240x45 durawood. The oregan looks to be seasoned & was previously the joists of a pergola by the look of them. The size of my deck has been stated. I know the oregan beam dimensions are a fraction light on but its a storage deck I will be building with an expectation of it taking say 500 kg's. No people no parties. What do you think of using the oregan instead of the durawood.

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## Bloss

mmm - I must have missed something?  :Confused:  I thought the design involved vertical posts sitting on the concrete floor with the deck platform 1.6m above that and clear underneath so a car nose or boot could sit underneath and the storage above?  :Confused:  That being so plastic wedges do not seem right.  :Confused:  
To secure perpendicular posts to a concrete floor you need to use a bracket such as the Pryda design (or other brands) or angle brackets that are fixed to the floor and bolted posts through the posts. Or is what you are talking about is posts bolted vertically against the outside walls with the raised deck being built full width across the shed between them? If that's the go then Utemad is on the money although I'm not sure why you need the spacers - the posts can bit hard against the concrete wall? But if that is what you will be doing then it is not a 'free-standing deck'. 
Maybe I'm just having a brain fade day - maybe a sketch would help? Anyway if you reckon you have enough information to do what you need don't bother trying to explain more to me - just do the job and put up some pics and when I see the end result maybe the little light in my head will come on . . .  :Redface:

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## UteMad

Mine the posts are against the side walls of the garage and bolted to the side walls with 12 x 125 gal dyna bored in .. posts sit on 10mm plastic packers to prevent any moisture being sucked into the bottom of the post .. if posts were freestanding then a pryda shoe or angle would be the go.. 
pick is the only one i had ready to go of a packer thats all 
utemad

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## Bloss

> Mine the posts are against the side walls of the garage and bolted to the side walls with 12 x 125 gal dyna bored in .. posts sit on 10mm plastic packers to prevent any moisture being sucked into the bottom of the post .. if posts were freestanding then a pryda shoe or angle would be the go.. 
> pick is the only one i had ready to go of a packer thats all 
> utemad

  That makes sense, but the OP description says 'free-standing' which implied the posts that held up the inner part of the deck at least would need fixing to the floor sufficiently well so that an accidental nudge by a car would not cause a catastrophe - which is another advantage of your design if you have back wall free to go all the way across or can build it high enough (as a mezzanine) to allow the care to go fully under, in which case it can be in the middle of the building (I did one of those in a 3m wall height shed that work really well).  :2thumbsup:  Anyway as I said - if he reckons what you've told him will work that's good enough.

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## Chain

It will be freestanding & attached to the floor only (no walls) using angle brackets. I should right now & will post a picture down the track. I had another question about substituting  twin 200x50 used oregan beams for the 240x45 durawood beams. The posting has not been listed yet.

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## Bloss

The 200x50 oregon beams over 3m should be fine - and in any case it'd be stronger if you check out and run the beams 100-150mm past each end post so the span would be 2700-2800. The only concern is to make sure the oregon beams are 'clear' or 'construction' grade - really with no knots going all the way through or any holes etc. If they have been used in the past in residential or commercial construction they will be fine. Just that sometime oregon used for concrete formwork pops up in S/H yards, ebay, etc and it is sometimes not suitable for long term load-bearing applications.

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## UteMad

Freestanding you will need to brace it fairly well .. mine is at the end of the garage so has walls on 3 sides.. so no bracing issue and the ceiling is well over 3m so i still have 2m under the beam and 1.3 above the floor.. being my bearer is only like 3m its a snack to freespan off all the side walls and drive straight under.. Freestanding is a bit more ivolved especially if you hit it with the car..  The pryda shoes take a good hard hit with a car .. had a balcony we built on the front of a house get hit by someone chucking a U turn in the driveway and it bent but held the balcony up.. creamed my one holding the carport up with my 3T plus 4by ute and it bent and i have never replaced it ... bracing is the big factor though  
utemad

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## Bloss

:What he said:  mainly front to back - ie: either from top front to bottom back or both ways on each side is best - timber or steel, or steel strap if both directions in X shape. Not as strong, but 45 degree brace on each post corner at the top - say 300-400 down would assist to. remember with bracing that at each end you need minimum of two fixings (bolts, screws etc) or you are wasting your time.  :2thumbsup:  If it is built correctly you will be unable to make the deck move with any force from your own body at any point - without a load or with a load on top. If there is any movement you haven't braced well enough IMO. I have seen decks 3 or 4m high that can be made to sway with just a person pushing - not properly built IMO although just to spec . . . :2thumbsup:

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## Chain

Thanks fellas
I now have a definite course of action.  :Biggrin:  (almost)
One thing is certain. This deck will be braced way above normal standard.
Underneath, my 1985 240 GL Volvo will spend its stationary time. It's only got 69,000 kilometres on the clock  & is in immaculate condition. I really like this car. God help the deck, or the builder (me) of the deck that causes  injury to the car  :Cry: .
Cheers

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