timber decking

[XT4V]

Hi all

I am new to these forums, and first of all, from an outsider perspective, I think it is a great forum to post, especially with all the experienced builders/tradesmen/members who post.

I am currently building a property in Mulgrave, Victoria which is nearing its completion stages.

I have some nice bi folds which I want to finish off with a timber deck out the back.

I have done a search, but couldn’t find the answer to the following questions. Before I ring the council and waste their time, I thought some of you may know the answers:

1) Do I need a building permit to erect the decking? It will be approx 5m x 4m and the FFL will be approx 250 off the ground
2) Is there a minimum requirement between ground and bearer?
3) With regards to stumps, what do people use? Timber or concrete?
4) What is the maximum overhang a timber deck strip can hang over the edge of the joist at the end of the decking (if this makes sense)?

Thanks for your help 

[ThePope]

1) Do I need a building permit to erect the decking? It will be approx 5m x 4m and the FFL will be approx 250 off the ground

Depends on your local council, some do require, some don't. Here in Canberra it's not required for anything 1 metre or less above ground level. Personally I'd never bother arsing about with permits for a standard timber deck but if you're worried about it then check with the council.

2) Is there a minimum requirement between ground and bearer?

No, bearers for the deck can be at or even below ground level as long as you use suitable timber. You also may need to make allowance for any drainage issues that may be present under the deck.

3) With regards to stumps, what do people use? Timber or concrete?

Being a carpenter I'd have to say timber, far easier to work with than damn concrete

4) What is the maximum overhang a timber deck strip can hang over the edge of the joist at the end of the decking (if this makes sense)?

Max overhang...how much would you like, will it likely be walked on or have pots plants on ect ?
I wouldn't want to see anymore than 100mm or so.

[XT4V]

thanks for the reply.

What did you mean by drainage under the decking? What needs to be looked at, slope away to make rainfall exit?

The decking will be right over a stormwater pit, so I am thinking to maybe dig a fall to the pit so all water runs in there.

I will also put down the black plastic to stop grass/weeds which will also help the water fall into the trap/pit if this makes sense?

[ThePope]

I only mentioned drainage because your height is very close to ground level and you seemed to be hinting you wanted to go lower than 250 "Is there a minimum requirement between ground and bearer?"

If your deck framing is on or inground you don't want to be trapping water under there and creating a swamp. Soil type, slope of land ect will determine how much of a problem it may be. So it's just something to bear in mind when you build it.

[XT4V]

another question that has come to mind, if I have a peice of deck surface say 3m in length, where is the best spot to join 2 peices together to get a long span (i.e. 6m), is it best to join over a joist (e.g. 1 peice of deck has 22mm of joist to hang on, and the other has the same?)

appreciate the advice, and sorry if these questoins sound very newbie like

if this doesnt make sense, I will draw some pics in ms-paint lol!

[ThePope]

yes, yes, yes....
must join you're decking boards (deck surface) on the middle of a joist.

I have a pdf file that gives a good rundown on deck building, if you like I'll email it.

and yes they are 'newbie like' but that's quite alright

[XT4V]

yes, yes, yes....
must join you're decking boards (deck surface) on the middle of a joist.

I have a pdf file that gives a good rundown on deck building, if you like I'll email it.

and yes they are 'newbie like' but that's quite alright

excellent. if you could email it to [email protected]

[ThePope]

on it's way...

[XT4V]

thanks heaps

One small question that comes to mind, how to make sure that all posts are at the same height? Do you dig different depth holes, or do you just trim the tops with a saw?

[julianx]

cut the tops off
I generally use gavanised concrete stirups, they are a galvanised steel braket that gets concreted into the ground then the posts are bolted to them. they keep the timber off the ground. With fear of contradicting the pope I,m fairly sure you must have 150mm between ground and the bottom of the sub floor framing, you do up here in qld, I could be wrong for other states. A good way to increase the gap is to use joist hangers so the joists are fixed to the side of the bearers instead of the top there by increasing the gap by the depth of the joist.
If you are digging post holes near a stormwater pit remember to be mindful of pipes.

[ThePope]

Yeah you're right on the clearance, not entirely sure it applies to external decks though. Anyway, having some clearance is always better than none which I should have said originally.

[XT4V]

Thanks again guys

I might go the joist hangers, it will probably make it a lot easier. Will that mean that the bearers take some of the load off the joists as they are the same level?

If I were to go the stirups, how deep do the footings for them need to be? I am guessing 400 minimum? Also, will 300x300 be sufficient width/length for each stirup

[Pulse]

About the overhang, up to 25% of span is allowed, therefore 2m between joists gives up to 50cm overhang. Steel posts are another alternative but wood is better for your first go.

Cheers
Pulse

[boban]

About the overhang, up to 25% of span is allowed, therefore 2m between joists gives up to 50cm overhang. Steel posts are another alternative but wood is better for your first go.

Cheers
Pulse

I dont know of any 19-25mm timber decking that can overhang by 500mm. You may thinking of cantilevering joists not decking. It would be like a diving board.

[XT4V]

thanks for the reply.

What did you mean by drainage under the decking? What needs to be looked at, slope away to make rainfall exit?

The decking will be right over a stormwater pit, so I am thinking to maybe dig a fall to the pit so all water runs in there.

I will also put down the black plastic to stop grass/weeds which will also help the water fall into the trap/pit if this makes sense?

any advice on this?