Calculate the price of a deck - Mother of all posting!!

Sorry Adrian but there are some serious flaws to your plan.

-90x45 treated pine CANNOT be used as a bearer nor wil it span 1500mm as one.
-Bearer span/ post spacing depends entirely on the size of the bearer - they do not have to be 1500mm apart to be solid.
-Bearers should be rebated into a post, not sit on top
-It is not recommended to use green hardwood for joists as it can season and shrink at different rates and cause an uneven decking surface.
-The BCA states joists must be 450mm apart NOT 500mm - all decking in Australia is designed for that span
- 5mm is too wide for a gap between decking boards - a 3mm gap achieved by using standard decking nails is sufficient.
- Decks under the building code must be a minimum of 300mm above the ground

A few other points of interest:
-hardwood decking has to be pre-drilled regardless of whether your using a nail gun
-you can get the 'twist' nails to suit a coil type nail gun
- fixing decking with screws is a much better method, they hold better, alow the deck to be sanded if need be as the screw sits just below the surface and the decking boards can be removed easily if need be.

I know its an old post, I hope any who have read it have checked the BCA to see its inaccuracies

Duke, what do you mean that the joist should be rebated onto the bearers? What does that mean?
All the decks I've seen have the joist sitting on the bearers.
Thanks.

In relation to the post/bearer/joist size and spacing.

On the deck I built recently, the posts were 1.4M apart in both directions.

I then used 140x70 (laminated 2x 140x35) TP for the bearers. These were 9m long and laminating them allowed me to stagger the join.

Joists were 90X45 TP and 40cm apart.

Decking was hardwood 70X19, and I screwed it down. 3mm gap between.

Everyones different. But I'm comfortable with the decisions I made.

I said the bearer should be rebated into the post

90x70 would have been sufficient for that bearer span.
400mm is closer than neccesary for the joist spacing, not a problem just means you probably had a joist or two extra.

-90x45 treated pine CANNOT be used as a bearer nor wil it span 1500mm as one. AB -AGREED - MUST BE HARDWOOD
-Bearer span/ post spacing depends entirely on the size of the bearer - they do not have to be 1500mm apart to be solid. AB - JUST MAKE SURE YOU DO NOT GET A SPRING
-Bearers should be rebated into a post, not sit on top AB - AGREED, UNLESS THEY ARE CONCRETE POSTS
-It is not recommended to use green hardwood for joists as it can season and shrink at different rates and cause an uneven decking surface. AGREED
-The BCA states joists must be 450mm apart NOT 500mm - all decking in Australia is designed for that span
- 5mm is too wide for a gap between decking boards - a 3mm gap achieved by using standard decking nails is sufficient. THAT WORKS TOO, I FOUND THE SCREWDRIVER EASIER, FASTER AND DIFFERENT SCREWDRIVERS CAN HELP REDUCE HALF BOARDS
- Decks under the building code must be a minimum of 300mm above the ground AGREED

A few other points of interest:
-hardwood decking has to be pre-drilled regardless of whether your using a nail gun ALL DECKING SHOULD BE PREDRILLED, ESPECIALLY PINE.
-you can get the 'twist' nails to suit a coil type nail gun YAY!!!
- fixing decking with screws is a much better method, they hold better, alow the deck to be sanded if need be as the screw sits just below the surface and the decking boards can be removed easily if need be. TRUE, WILL TAKE A LITTLE LONGER IF NO CORDLESS DRILL.

I know its an old post, I hope any who have read it have checked the BCA to see its inaccuracies

Thanks Luke, have made a few adjusments.

Also note some councils require a permit for large decks.

For a bearer span of 1500mm I would normally recommend 90 x 70 GL8 treated pine. If hardwood were to be used I would recommend kiln-dried over green.

Wow, this is informative & helpful. Council has approved our plans to build deck and pergola. The deck will be 50sqm - so, I'm glad that you started this thread Adrian

Will show it to DH cos' this is one of the next project due to start soon

To Adrian / Luke & all other experts in the field of decks...

Firstly a fantastic & very informative post AB.

It's finally my turn to build a deck! Have had a few rough guestimates on a cost to do the whole job & they are very SCARY

Got chatting with a mate recently about it & it just so happens that he has built a deck or 2 in his time .... big saving on labour. Now to the materials.

He has given me a list of timber I will need. Now it all looks Greek to me so hopefully someone can decipher it for a novice like myself. It was sent as a txt...

Redried treated pine
140x45 1/6.0 11/5.4
31/3.6 2/2.4
90x90 7/2.4
90x45 10/6.0 2/5.4
2/4.8 2/4.2
70x35 4/4.8 2/4.2
100x100 1/6.0
140x19 Merbeau deck
600 Lineal mts
90x19 Merbeau deck
160 Lineal mts

OK, what sort of $$$ would I expect to pay for all of this? Obviously this is just for the timber... nails, cement, etc will be extra.

Any help will be appreciated... Also any comments / improvents are a great help too.

Cheers,
Mike.

IN round figures Mike its about $6900. Thats an aweful lot of timber, must be a massive deck. I quoted it using 140x25 merbau decking, its not available in 19mm thick at that width from memory.
There doesn't seem to be any bearer size material there - let me know if you need any help with spans/sizes etc.

Hi,
I'm pretty sure there is merbau 140x19. My friend bought it not long ago. Firthy, what is the size of the deck you want to cover?

Thanks Luke.

As I said, the measurements all look Greek to me so not sure if everything I need is there. Just had one quote from a timber yard & he came up with $7500, so I guess it's around the mark.



Above is where I plan to lay the deck.... Yes, you're right, it is huge!

Any suggestions / changes will be appreciative.

Cheers,
Mike.[/url]

Question:

I am planning a truly enourmous deck that will be raised 2.56m above the ground (the height of our basement). Under the deck will be a number of water tanks which have a diameter of 1.86m. Clearly I need to be sure that I can span the 1.86m (lets say 2m) without needing a post in the middle as you can't put a post through a water tank!

Where would I find out about what specification of timber and fixings I would need to achieve this?

Also considering the posts will be 2.56m above the ground, how deep would I need to sink them into the ground, and is there some special specification of concrete needed to hold them in?

I presume also the posts are going to have to be cross-braced?

I really hope someone has some expertees in raised decks...!

Thanks

Simon

There is 140x19, isn't that much cheaper than the 140x22 or 140x25

I worked out $6823, thats a timber yard quote with 140x25 decking.
Don't forget you'll be up for about $500 at least to coat the deck plus all you fixings. I'd suggest looking at some composite decking, especially if the majority of the deck is uncovered. It is dearer but you will never need to coat it.
http://www.monarchdeck.com/advantage.php

The 2 metre span is easily achievable and its not actually that high, I've quoted one 6 metres off the ground. Is the deck going to be attached or freestanding??? If its attached I'd recommend pouring 450mmx450mmx450mm footings with 300mm post anchors inside them. A post can easily be replaced in the future if its in a stirrup.
Your joists will need to be 140x45 treated and bearers 140x70 for those spans. Cross bracing the posts is a good idea.

Hi Luke, thanks for the answer. I was going to attach the deck to the house, but previous advice given on this thread suggests that should not be done?

What do you reckon?

SImon

An attached deck is much more stable as it has the house to keep it rigid - important when high off the ground.

Dynamic - check with your engineer first - re attached or not - most engineers like to know what "extra" forces are going to affect the building when they design it, or at least know about that they need to consider.
Duke no offence - just a bit of past experience.
Steve

Thanks both of you - I'll check with my engineer.

Simon