Deck building calculator / help for prices

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KennyM

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#114484 21-Feb-2013 10:17

Hey,

Basically wanting to extend/replace the existing deck, but need to be able to get a estimate on how much timber is required so I can get a price to do it.

The price im after doesnt allow for the steps or perhaps a ramp, but just the general gist of the main deck, I can work out the rest when its all underway

Foundation is for the 'new deck', but the top decking itself is for the whole area, as will be replacing the top of exisiting deck, new foundation heights will meet old ones.

I have calculated:
26piles
10bearers (2.4meters long each)
90meters of Joinsts
350meters of decking.

I can work out concrete, joist hangers etc from this so needs to be kinda accuate, but i expect im going to be a bit short on decking due to steps etc, just need estimates at the moment.

More than happy to supply any other information that could/is needed to help work this out. But I just dont know what else to put in here.

Notes: The deck comes 1300 off the house, there is another room that comes out 1800 to the edge of the deck.
Not quoting laybour/time as ill be doing it myself, how long it takes me doesnt really matter.

Edit: The picture is turning square and im not sure how to fix it, Orginal is pretty much to scale - https://lh5.googleusercontent.com/-LN8njefLbU4/USU6SL6kocI/AAAAAAAAAW4/sjaMHoYLIcQ/s1149/new+deck+2.jpg

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#766870 21-Feb-2013 10:21

Assume you have a council permit to build this deck?
Also assume you will add this extra sqm to your house insurance policy?

These two very important items above may increase the cost per sqm for your deck !
(cool deck by the way)

NonprayingMantis

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#766873 21-Feb-2013 10:31

what are you actually asking for?

It looks like you have calculated the amounts of timber already

If you are doing it yourself then I wouldn't worry about calculating how many nails, hangars etc you will need ahead fo time. just get a rough idea, buy a bunch and then when you run out buy some more.

coincidentally I have just finished a project that is a remarkably similar size and shape to yours, It also involved extending out an old deck and replacing the old decking plansk with new ones

26 piles seems a little excessive given the size you are working with how high off the ground is the deck planned to be? if the piles are low like mine (see below) then 1/2 bag of concrete per pile is fine

I used:
9 piles 60cm long (30cm in the ground, 30cm above the ground for the bearer to hang off) I could hang the bearers off existing deck on one side and retaining wall on the other)
4 bearers (6m long) 200x50 H4 rough sawn
10 joists (~4m long) H3.2
400 linear m of clear decking (the best quality pine stuff)

total cost from bunnings for the timber above without any fixings was around $2k including delivery.

hangars, bolts, screws (screws are much better for decking IMO) etc came to roughly $350 IIRC

Stain (yet to be applied - need to wait for decking to weather for 6 weeks) is around $300 for 2 coats

NonprayingMantis

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#766874 21-Feb-2013 10:32

Gooseybhai: Assume you have a council permit to build this deck?
Also assume you will add this extra sqm to your house insurance policy?

These two very important items above may increase the cost per sqm for your deck !
(cool deck by the way)

AFAIk you don't need a permit for a new deck unless it is more than 1.5m off the ground

KennyM

221 posts

Master Geek
+1 received by user: 10

#766892 21-Feb-2013 11:12

NonprayingMantis: what are you actually asking for?

It looks like you have calculated the amounts of timber already

Sorry I should have been a bit more clear, I worked it out, but wasnt sure if it worked it out correctly.
I worked the piles out to be 1200 apart from each other.
I am going to screw it down, as ive been seeing a lot of decks latly with nails coming back up (the existing deck is starting to do this too)

Had planned on the piles being H5 and everything else being H4, but need to double check thats right.

I hadnt thought about insurance, that is a good point and will look into it.
Had thought about the permit, its about 500 off the ground, and instead of having any drop offs anywhere, will just do steps down the 2 edges.

NonprayingMantis

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#766911 21-Feb-2013 11:26

KennyM:
NonprayingMantis: what are you actually asking for?

It looks like you have calculated the amounts of timber already

Sorry I should have been a bit more clear, I worked it out, but wasnt sure if it worked it out correctly.
I worked the piles out to be 1200 apart from each other.
I am going to screw it down, as ive been seeing a lot of decks latly with nails coming back up (the existing deck is starting to do this too)

Had planned on the piles being H5 and everything else being H4, but need to double check thats right.

I hadnt thought about insurance, that is a good point and will look into it.
Had thought about the permit, its about 500 off the ground, and instead of having any drop offs anywhere, will just do steps down the 2 edges.

looking at your plan I can't see how you need 26 piles if they are 1.2m apart.

looks like the total area of the new deck is about 18-19sqm
If you can hang the bearers off the old deck, then you don't need that many piles

so, for example, on the left hand side of the drawing where you have 2.6m long, you can use only 2 piles in there spaced at 1.2m (with a bit of an overhang, which is fine), then your total width is 8.2m means you need 7 going accross. 7 x 2 = 14. add in a couple more for the 'dog leg' part on the top right and you can do it with around 16 piles.

Piles ideally should be H5, but H4 is ok too.
anything that is not touching the ground can be H3.2

if it's 500mm off the ground then you don;t need any council permission. just go ahead and do it.

Bung

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#766932 21-Feb-2013 11:45

AFAIK the building code now requires piles to be H5. anything clear of ground can be H3.2 but sometimes there isn't much difference in price to go H4 for joists and bearers.

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wallop

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#766946 21-Feb-2013 12:15

I presume you are going to use stainless screws. Make sure you shop around for them, I priced mine at Placemakers and nearly had a heart attack. Went to Carters and got 1000 screws for less than the Placemakers 500 screw price so saved over half the price. The last lot I needed I got direct from the supplier for about another third - half off the Carters price. That was a fluke though, the guy who served me asked what discount I normally got from Carters and I was'nt sure so he gave me a good discount.

wallop

367 posts

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#766954 21-Feb-2013 12:19

And where are you and what decking are you using? If you are in Christchurch Hardie and Thompson have finger jointed kwila for a good price and all lengths are 5.3m (I think thats the size).

NonprayingMantis

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#767002 21-Feb-2013 13:04

wallop: I presume you are going to use stainless screws. Make sure you shop around for them, I priced mine at Placemakers and nearly had a heart attack. Went to Carters and got 1000 screws for less than the Placemakers 500 screw price so saved over half the price. The last lot I needed I got direct from the supplier for about another third - half off the Carters price. That was a fluke though, the guy who served me asked what discount I normally got from Carters and I was'nt sure so he gave me a good discount.

Bunnings do 1000 stainless steel screws for around $120

Jaxson

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#767021 21-Feb-2013 13:35

If you have time then do shop around. I got a whole heap of products from these guys for instance back when I installed a shade sail. I got 18 bits through them for less than 2 at Mega, including postage to my door.

http://clamp-products.co.nz/

Not saying they'll do screws etc, but just letting you know in general.

Little

83 posts

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#767033 21-Feb-2013 13:44

NonprayingMantis:
wallop: I presume you are going to use stainless screws. Make sure you shop around for them, I priced mine at Placemakers and nearly had a heart attack. Went to Carters and got 1000 screws for less than the Placemakers 500 screw price so saved over half the price. The last lot I needed I got direct from the supplier for about another third - half off the Carters price. That was a fluke though, the guy who served me asked what discount I normally got from Carters and I was'nt sure so he gave me a good discount.

Bunnings do 1000 stainless steel screws for around $120

Just bought 2000 from these guys:

http://www.trademe.co.nz/building-renovation/building-supplies/fixing-fastening/screws-bolts/auction-563304967.htm

1000 @ $69

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Niel

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#767302 21-Feb-2013 20:26

Depending on where you are, Anzor is a great supplier of stainless steel fittings/fasteners.

Our deck is nailed down every 600mm, been great for a year and nothing pulling up.

A company in Auckland called Chemical Packers makes a timber stain that is like water but contains pigments and resin that last a long time, not dies which last 6 months. Applies very easy as it is runny. Also listed on TradeMe. The guy formulated it because he could not find anything on the market that actually lasts. Highly recommended.

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jonherries

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#767317 21-Feb-2013 21:02

On the Australian "The Block" in the last series, they had some sort of clip in system so no nails and screws. Not sure what the product is but the finished article was impressive.

Jon

Edit: sp

Wilko

62 posts

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#767319 21-Feb-2013 21:08

If any part of the deck is over 1 metre above ground level, a building consent is required. Also, a deck that is more than 2 metres wide from the house requires bracing to the sub-structure, which has to be calculated by someone who knows how to do the calculations!
Even though a permit may not be required, the structure still has to comply with the Building Act. Usually you need to use NZS 3604 as the guide for pile spacing, and bearer and joist sizes and spacing. If there is greater than 1 metre from any of the deck edges to the ground, an approved handrail must be included.
I think that both Placemakers and Mitre 10 have pamphlets which help with building a simple deck, with suggested sizes of joists and bearers. That may give you an idea of how to go about planning and building what you want.
Also, there may be resource consent issues if the additional area of the deck takes the total site coverage over that allowed by the Council's district plan. If you are on a cross-leased section, there may be requirements for obtaining the other people's approval and the plan of the deck may have to be added to the Survey Title (which means lawyers!!).

mattwnz

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#767344 21-Feb-2013 22:10

Best to check with the council anyway to see if a consent is required. Some TAs have their own rules. I think the NZ building cose also has the rules for decks, and that is free on the dept of building website. NZS3604 will have the calculations you need in terms of piles and bearer spacing and sizing, and bracing. Free access at your library to this.

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