Driving me crazy!

[dub3media]

Just working on a deck at the moment which is 1400 from the ground and have dug the holes for the Posts H5 Rs 125x125, and the posts are ready to be concreted.

The deck is 4 m along the house and 5m out towards the grass bank.

Im so confused as to the bearer spans etc.

My bearers are 2 2x 140x45 H3.2
My Joists are 140x45
My decking is 20mm and spacings are 450's

My question is how far apart can the posts span in the row and what distance can posts be from a new row of posts.

How do you determine the floor load of a deck?

I have also seen some pics of the joist being covered in black plastic, is this necceassary, never seen it anywhere else.

I tried downloading the software that is mentioned on this forum but the link must be dead.

Some help would be nice as I am wanting to concrete the posts in tomorrow but reading more and more, gets me more confused and worried i havnt got the rights spacings.

I have the posts 1700 apart and 1700 from the next row. Is this right?

So three lines of posts 1700 apart.

I want to canterliver the josts, what distance can you do this, I heard rule of thumb is a third of the total length is this correct.

Also the first row of posts I have decided to check and out the post 20mm either side and fix my one bearer either side and coach bolt it with washer and nut on one side, as you will see in the pic these posts are the highest from the ground which is a concrete pad below, but for the other posts which basically sit close to the ground i am just going to skew nail the dbearer into the post with one z nail either side of the bearer into the post?

Is this ok or should I bolt all bearers to post?

[Paul2012]

When i recently built my deck i went off the Mitre 10(Hardware) " How to build a deck" brochure, for post spacing , it said to dig posts 1.8 out from the house and then 1.5 across.
I would think 1.7 would be fine.


In regard to skew nailing the bearers to the posts personally i would not do this i would spend the time and notch out all the posts and bolt the bearers.
Paul

[Barry_White]

It appears that Mitre 10 NZ doesn't have a link to their plans but here is the link to the Aust. Mitre 10 Build a Deck plans http://www.mitre10.com.au/DIY-Central/Mitre-Plans/_category/Build-It/_name/Build-a-deck/

[dub3media]

thanks guys good advice and yeah paul have decided to notch out the posts, for a 15x125 post is 25mm both sides ok ? one bearer either side?

[Paul2012]

You might need to wait for further advice from some of the senior members of this forum as i have only built the one deck.... But from what i have researched for decks over 1 metre you need to fully house the bearer so you would need a notch of 45 mm.if you are using 140 x 45...

I have not seen too many designs where the bearer would be on either side as in this case you wouldnt be able to notch out this much either side as there would be hardly anything in the middle.... Personally I would use one bearer per post and fully house it 45 mm


cheers paul

[Skew ChiDAMN!!]

have you looked at using Joist Hangers? (www.multinail.com/pdfs/JoistHangers.pdf)

[dub3media]

Yeah using joist hangers against the house ledger, Double bearer one either side housed into post, then joist over bearer butting into ledger with joist hangers. Someone told me not to but Joist into the ledger board rather to have them on top, but I got height issues? is this a major?

[Brickie]

How do you determine the floor load of a deck?



Friends x grog x BBQ + food = load

[brynk]

gday dub3media

joist hangers if installed properly will be fine as they are rated to accept residential floor loads. the thing to consider as well is the frequency and size of the fixings you use on your whaling plate (ledger). pryda fb4590's for your joist hangers with 10 nails will match the strength of the dyna's.

i would suggest 1 x M8 (10mm dia.) x 100mm dyna for 2 joists - this will exceed your requirements by roughly 4 times the design load but the size down will not be long enough to be practical - be sure to drill into the brick itself 55mm deep, no closer to any edge than 1/2 the brick's height. the specs also say do not get closer than 100mm to a corner of the wall you are fixing to.

if you're not familiar with setting dyna's - be sure to hammer them in with the nut on the thread, the nut should be wound onto the thread so a small piece of the nut itself extends past the top of the thread - when you strike it with a hammer the nut will protect the thread from damage. use a suitable washer & drill the hole in the whaler 10-20% larger to allow for movement, to protect your brickwork from cracking.

r's brynk

[brynk]

looking at your photos i see the whaler is already on; looks stout! :U

[dub3media]

Yeah brynk I was going to fix the ledger to the block wall but then because of the height issue with the retaining wall and the size of the deck that was extentending out to the grass had to fix it into the floor joists, (end grain) I asked my boss at work about this and he said it would be fine, used 150mm coach screws drilled a pillot hole just into the floor joist to stop them from splitting, feels solid !

[dub3media]

dont know if you can see from the pic but there is an overhang of 200mm from the cladding to the block wall, couldnt pack it out that much