Advise on bearers and Joists

[dan76n]

Hi all,
Im about to start my deck around my pool but Im a little stumped as to what to do with the bearers. The guy who installed the pool said not to attach anything to the pool walls which i thought was a bit weird because all the pools in my neighbourhood that have decks have the bearers dynabolted to the wall.
Im also not sure how to do the other side as its a sandstone retaining wall so I dont want to bolt the bearer to that.
If I do posts I will be forced to have my joists overhang the bearers, Is this ok?
I only have 240mm from earth to top of pool copping so I am thinking I will have to use 90 x 45 Treated hardwood for both the bearers and joists, I have seen this done a bit but am unsure if its my best option.
the gap between pool and retaining wall is 1200mm and 645mm at the pool step.
Any help is welcome.

[frog's wife]

What about sitting your bearers into the stirrups of ground screws? No post hole diggin, can get pretty close to edge of pool which means very little overhang for your joists or can you just hang your joists off the inside of the bearers?

Just a girlie opinion and I'm sure one of you more knowledgeable blokes will point out the dozen reasons why not.

[billbeee]

Dan
Personally I'd be using something like brick pavers, I hate timber sitting so close to the ground, rot, need for drainage, vermin refuge etc.
For a timber deck I'd make sure the backfill compaction is OK all around the area, then I just pour a few flat pads of concrete at near enough the right height. You can always pack the bearers a touch if you are out.
It should all just sit there, no complicated fixings.
Best of luck with it.
Cheer
Bill

[dan76n]

Billbeee,
I dont quite understand. Are you suggesting I lay a slab and then rest the bearers on it?

[billbeee]

Dan,
No, not a full slab, you could just set 200 x 100 x 100thick besser blocks on the ground, at positions you would normally put a pier if you were going higher.
The blocks you buy may be OK for size but more than likely they are not, so mix up your own concrete, a very dry mix and put pads down. No need for formwork unless maybe at the edges where it may be seen.
Cheers
Bill

[dan76n]

Ok, so do I attach the bearers to the slabs or just allow the weight itself to hold it in place?

Also I was told I should go 600mm deep when concreting in posts for my last deck. wouldn't a small pad be a little under done?

[mako]

Gday. As long as the ground is compact enough i would dig stump holes 400mm (deep) x 300mm and use 90 x 90mm treated pine stumps. For bearers/joists you could use 90 x 90 treated pine bearers on the stumps the 90 x 45 treated pine joists on that. If you are using say merbau decking it will be 20mm thick (actually 19mm) so the total hight from top of stumps will be 200mm. This will give you about 40mm off ground which isnt ideal but can be done. The other option is to put stumps in as before and use 140 x 45mm treated pine bearers to side of stumps and have the same size joists sitting 'internally' between the bearers using joist hangers. This would give you 80mm clearance from ground. If you use the first option you can overhang the joists no ore than 300mm. Hope this helps:U
PS Stumps concreted into ground on H4 treated or redgum sole plates.

[billbeee]

Just the weight should be OK.
If you are worried about a bit of movement you could plastic plug to the walls here and there, screw or drivepin, with a bracket fix. No big deal all the weight is carried on the ground.
Cheers
Bill

[bpj1968]

Which direction are you going to run the decking, may affect your choice of bearers/joists. Also I hope you have sufficient drainage around that area. Not sure of the long term effect of the pool chlorine / salt will have on the choice of stumps. May need a high hazard rating H5

[silentC]

The area between the pool and the fence, I would back fill and pave. The area that extends out into the yard (I presume there is one) I would either build a low retaining wall, back fill and pave, or I would set up TP bearers and joists as per mako.

[mako]

if you are worried about stumps rotting you could fill holes completely with concrete and use bolt down galvanised post stirrups. This would add 35 to 40mm to the hight though.

[dan76n]

I have added more pics to give a better idea.
my deck will go to the edge of the pool wall which is 950 above the ground.
I will make sure the ground below retaining wall is slopping with natural ground level so drainage shouldnt be an issue.

[silentC]

OK well in answer to your original question there's absolutely no reason you can't put in a row of stumps set back from the walls of the pool and the retaining wall and have your joists cantilever over the bearers to get them in tight to the pool and the wall. I have done one like this. I used 90x90 TP stumps with 90x75 TP bearers and 90x45 joists. I had to put in a lot of stumps because of the size of the bearer - about one every metre.

On the downhill side, you have more headroom and you can do it with a deeper bearer so less stumps needed but it will possibly need diagonal bracing in the bottom corner.

I would still consider paving on the uphill side. You have a natural retaining wall in the pool. It would be simple to back fill, spread some crusher dust, compact and throw some pavers down on it.

[dan76n]

I cant seem to find any 90 x 75 or 90 x 90 TP for the bearers as suggested?
Would it be ok to use two 90 x 45 together?

[mako]

Yep two 90 x 45 's put together is fine. just nail them every 600mm and on each side so they are really stuck together. It is actually cheaper to do this than use 90 x 90.

[dan76n]

so what would the maximum span be for the posts be using two 90 x 45 for bearers?

[silentC]

My span tables don't show 90x90 but a 90x70 in F5 will span up to 1200 or 1500 in F8.

[mako]

1500mm max between posts using two 90 x 45's (or 90 x 90 ) and 1500mm for the joists ( 90 x 45). This is max though and although will do the job and is legal it will have a little spring in it . Better th bring them all in a little if you can.

[bpj1968]

I had a look at the tables I have and don't show 90x90 in F5.

Bearer span also takes into account the joist span. Longer joist span = less bearer span, as each bearer is now supporting more floor.

Try this for a program for workiong out spans

http://www.woodworkforums.com/showthread.php?t=55014

[silentC]

Yes, the spans I gave were for a bearer spacing of 1800, but given the tight space between the pool and the retaining wall, he's not likely to exceed that. Possibly on the downhill side though - however I'd suggest a much deeper bearer for that portion of the deck.