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 :D

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] :D

[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? :D

[ThePope]

Yeah, sounds reasonable if you want to grade the surface into your pit.

"Will that mean that the bearers take some of the load off the joists as they are the same level?"
Not entirely sure what you're asking here.

And the footing size you mentioned is fine.

[Pulse]

Sorry Boban, Talking about joist cantilever not decking overhang, my mistake

about the drainage make sure it drains away from the house. Weed mat would be better than black plastic. Cover the mat with gravel and slope towards drainage pit and away from the house.

As far as the bearers taking some load off the joists, obviously the one decking board on the bearer is supported by the bearer only but that makes no difference to the design at all.

Cheers
Pulse

[XT4V]

thanks for the advice on all above questions. now that is all out the way, I have a few design questions I need answered by you blokes

With the decking I am going to build, I am thinking of using the following:


90 x 90 treated pine stumps
90 x 45 hardwood bearers (is f14 suitable, do I need to treat it with something to prevent rot?)
90 x 35 hardwood joists (same as above, does it need to be treated?)
Not sure what size, but merbau reeded ad deckingFew questions:
1. With the 90 x 45 bearers, what stump spacing is required? From memory, it will be 1200?

2. Will joist span of 450 centre to centre be sufficient?

3. What nails should I use for nailing the decking material to joists?

4. What nails should I use for nailing bearers to stumps, and joists to bearers (NB: I will be using joist hangers).

[kobes]

on it's way...
Hi ThePope
Could you possibly send me the pdf that you have sent to untamed -([email protected])?
I am also in a similar predicament with my deck, and am a very, very much a 'newbie!!.

It will be 36m2 with 3x1 steps at differing locations.
The deck will be partially laid over an existing concrete surface and attached to the brickwork (Bottom course) on the house. The concrete is sheltered by the house - will I be able to attach joists and bearers directly to the bricks and concrete, without great issues?

I am using 1.8mx200mm dia round posts at 1m spacings around the far garden edge, with recessed diagonally laid 60mm blackbutt boards.
Ground clearance should not be major concern, however drainage will be. The ground slopes toward the house and is heavy clay. I have two stormwater drains on the lower/house edge which I intend to 'channel' water too, over weed-matting...

- this is probably the biggest task I have ever undertaken in home reno, so am treading gently and leading up slowly to Build day (Wife and her Mum are giving me heaps for all the delays!! lol!)

If anyone can advise the best place to shop for appropriate Joists, bearers, posts, boards, - in fact the whole thing, this would help greatly - I live in Greystanes NSW.

I have read this thread and siphoned off great info to help so far, but anyone who feels that they can advise further will find me forever grateful.
Cheers

[ThePope]

untamed...
the deck is 5x4m isn't it, which direction do the bearers run and does the deck attach to the house on one or more sides.

[ThePope]

will I be able to attach joists and bearers directly to the bricks and concrete, without great issues?

Is usually a simple affair, but you need pay attention to how water runs off the concrete (patio I guess) and not trap it when you lay the deck framing on top.

[XT4V]

it is about 4.5 (length ways, the way the deck boards run) x 3.5

The deck will connect to the house by the way of 2 ledgers. One of the two ledgers will act as a beam/bearer, the other will be a connection point for the other beam(s). Can I use joist hangers to connect up bearers to a ledger?

If the above didnt make sense, I will need to draw it up and post a scanned image.

[ThePope]

ok this is the way I'd do it,

90x90 posts, fine
90x45 bearers, change to 150x50 hwd
90x38 joists, change to 100x50 hwd

100x50 ledger bolted to one wall (4500mm)
just the one bearer in the middle, posts at both ends and three in the middle
as you're so close to ground paint your bearers and joists with creosote or similar
all nails galvanised and for decking use 50mm gal twist/deformed shank

"Can I use joist hangers to connect up bearers to a ledger?"
I wouldn't, so whack a post under

[XT4V]

sweet, thanks for the plans and advice.

I dont think its possible to run posts under the beams at the second ledger wall due to a stormwater pipe running the lenght of that wall. That and the fact that I dont want to be mashing up concrete footings.

Will it be structurally sound to mount the bearers to a second ledger, or is it too dodgy?

[XT4V]

I have drawn a plan in mspaint. I used a span table for F17 hardwood which will still allow me to get away with 90x45 bearers for added ground clearance (http://www.pryda.com.au/uploads/mbst%20f17.pdf). I hope I have understood this table correctly, otherwise my deck plan is way out of wack :cool:

can you please review my deck plan and give feedback on it? I know you have advised not to use a second ledger, but its a very tight situation :( I havent drawn in the joists, but they will be hung with joist hangers and with 450mm centre spacing.

by the way, correct size of deck in pic. 4.8 x 3.0

[aussieglen]

:) [quote=untamed]
With the decking I am going to build, I am thinking of using the following:

Few questions:

3. What nails should I use for nailing the decking material to joists?


I have just completed 2 decks (front and back) with teated pine 90 x 22 boards ( grooved face up) and have used "Stealth Decking Fastners" throughout (see link http://deckone.com/ ). They are not cheap but you dont need to nail the boards in the usual way thus punching :( and splitting :eek: is not an issue. I found them to be superior to nailing and the finished job without nail heads is more pleasing. :)

Hope this helps
Aussieglen

[barrysumpter]

This is the method I used for hard wood Merbu decking that split when using a nail gun:

"The standard strong suggestion is to predrill holes and use the twisted shank Gal nails."

http://www.woodworkforums.ubeaut.com...read.php?t=961

However, if you are using Soft Wood Treated Pine then you may be able to use a gun with the twisted shank gal nails.

The hammer head indents come out with time and weather changes with Merbu.
The splitting has only occured to 1 piece and was actually already there when the deck was built.
As I took great care in selecting each piece.

I've gone back over all nails only once since built.
And haven't noted the need to do so again since.

You may find heaps of other posts conserning how I built my deck.
I logged as much info on here as I could, for just this reason.

Search for: Sumpter Deck

I've also just picked up the follwoing at Bunnings:
Decks & Pergolas Construction Manual - 2nd Edition - by Allan Stains

And took a TAFE class for building Decks and Pergolas.



hth

[ThePope]

can you please review my deck plan...
from page 4 of your span tables:
Musclebeam F17 is not recommended for direct exposure to the weather or to humid inside conditions...

the engineered timber would cost you a small fortune anyway.

Ok, this is my final offer:)

Delete the 150x50 bearer and use either 90x90 TP or 100x75 hwd, sit on top of your posts and run some hoop iron strap around (blue). With either of those sizes you can reduce your posts by one, only need two in the middle.

90x45 TP or 100x50 hwd joists, using 35 or 38 you got much more chance of getting splits along the centre of the joist when you nail your decking on. As your deck is 3000 wide treated pine joists will be ok for that span (approx 1400mm)

Where you attach the bearer to the ledger get a length of 50x50 gal steel angle bolted on and the bearer can sit on that. Bolt it well around the ledger and bearer junction.

You can use standard F11 Hardwood or go for F7 Treated Pine, if it were mine I'd definately use treated pine.

[ThePope]

And took a TAFE class for building Decks and Pergolas.
hth

interesting, what sort of time span did the course run for.

[XT4V]

from page 4 of your span tables:
Musclebeam F17 is not recommended for direct exposure to the weather or to humid inside conditions...

the engineered timber would cost you a small fortune anyway.

Ok, this is my final offer:)

Delete the 150x50 bearer and use either 90x90 TP or 100x75 hwd, sit on top of your posts and run some hoop iron strap around (blue). With either of those sizes you can reduce your posts by one, only need two in the middle.

90x45 TP or 100x50 hwd joists, using 35 or 38 you got much more chance of getting splits along the centre of the joist when you nail your decking on. As your deck is 3000 wide treated pine joists will be ok for that span (approx 1400mm)

Where you attach the bearer to the ledger get a length of 50x50 gal steel angle bolted on and the bearer can sit on that. Bolt it well around the ledger and bearer junction.

You can use standard F11 Hardwood or go for F7 Treated Pine, if it were mine I'd definately use treated pine.

Awesome, thanks again bud. :D

What does the hoop iron do exactly? Also, where the bearer sits on the 50x50 gal steel angle, do I need to bolt the bearer to the angle, or can I just nail it from each side into the ledger?

[ThePope]

" What does the hoop iron do exactly?"
When that stormwater pit overflows it stops the whole shebang from floating away down the street :)

It just ties the bearer to the post nice and simply rather than relying solely on nails into the end grain of the posts.

"or can I just nail it from each side into the ledger?"
yep, that's fine

[XT4V]

" What does the hoop iron do exactly?"
When that stormwater pit overflows it stops the whole shebang from floating away down the street :)


hahha! good one :D

After careful consideration and good advice off you, I will steer clear off the hardwood and go with the treated pine, cheaper and easier to work with. I am starting to grade the area so I will probably commence work this weekend, just gotta order all the timbers through my cousin and get them delivered ;)

[ThePope]

the fee for this service...
plenty of pics, warts and and all

[XT4V]

no probs :)

I will go with 90x90 posts notched out for 140x45 TP bearers and 120x45 TP joists.

They say the 90x45 single span is 1300, so the deck might be a bit too springy for my liking. Better to go over-enginered than get disappointment from the handbreak (Mrs) lol! Shouldnt cost me too much more any how.

I am getting itchy to build this damn thing.

[XT4V]

Just wondering what I should be using to bolt the ledger to the brick wall? The bricks are hollow, not solid.

I have heard bad things about hollow bricks and dynabolts, and I dont want my deck to fall over when there is load on in :eek:

[ThePope]

They say the 90x45 single span is 1300
Latest timber framing code specifies 1400 for F7 but going up to 120 won't hurt.
Dynabolts can be difficult at times, so you have a choice of those, ramset plastic plugs or loxins.

read the pros and cons here:
http://www.woodworkforums.ubeaut.com.au/showthread.php?t=8017
http://www.woodworkforums.ubeaut.com.au/showthread.php?p=153805

ps: just noticed this has run to three pages, less talk more build required :)

[XT4V]

PROGRESS REPORT

This weekend, my old man and myself got to work with the shovels, picks and crow bars. I couldnt justify spending money on getting a little roo in to do the excavatoins, I would rather save the money for beer!

We excavated between 100-150mm of soil from the area and dug 8 stump holes approx 600 deep.

Cost so far: A few cuts and blisters :)

Getting the material delivered this week, so I will be doing a lot of work on the long weekend (friday/saturday/monday). Cant work Sunday due to Easter and family commitments.

Quick question: What are the legalities of running ag pipe to the stormwater pitt that is located under the deck? From memory, it is not allowed, but I am hoping I am wrong as I want to make the drainage under the deck unstopable!

[XT4V]

here is a long awaited update, nearly finished this friggen deck (yes I know I am a slow achiever, but its been on hold for a while).

I had the frame done a while ago and I layed half the deck boards over the weekend that just passed and will have it completed this weekend.

http://www.piranha.net.au/house/DSC00072.JPG

EDIT: yes it is close to the gound, but not much I could do with it :(

[ThePope]

doing well...

how the knees and fingers holding up :)

[XT4V]

cheers :)

knees, back & hands are all sore! knees the most though!! :mad: