Deck/carport

[Willo]

Hi,

(retyping this as some sort of log-out error???)

I'm desiging a deck/carport for the back of my house. It's 2m high, 6m long and 5.5m wide. There will be two rows of posts (5 in each row set 1.5m apart) that will be 2.5 from the house and then 5.5m.

1. I've read the span tables and would appreciate confirmation of the following:
Posts- 100x100 (what timber rating? F14?)
Ledger- 100x50 (what timber rating? f14?)
Bearers- 150 x 75 f14
joists- 150 x 50 f14 (450 centers, continuos spans of 2.5m, 3m)

2. With the joists, do I need 5.5 m lengths, or can I join two pieces above the bearers?

3. Can I bolt the ledger straight through the existing "foreverboard" into the house joist, or should I cut it away? Will bolts every 500 be sufficient?

4. Any suggestions to waterproof under the deck so the rain keeps off the car?

5. If two of the outer posts extend 2.5m above the deck to hold a shade sail, will the footings of 300x300x450 be sufficient?

6. I want to use second hand timber- so how can I assess the grade is f14 etc?

Hope you can help.

Cheers,
Willo

[ThePope]

You're building a carport and the top of which will be a timber deck, is that correct ?

Post a sketch of what you're doing with measurements on it if you can.

[mic-d]

Hi,
5. If two of the outer posts extend 2.5m above the deck to hold a shade sail, will the footings of 300x300x450 be sufficient?
Willo

Hi, When I did my sails (13sqm), the instructions suggested a footing depth of 400x400x800. For 25sqm sails a footing of 400x400x1200 was recommended.
Naturally, when I did mine I overengineered them and went the larger size. When the dingo guy arrived, he only had a 600mm auger so I ended up with a couple of bloody big holes you could have buried someone in. The sails are still there tho'
I would also fit a piece of concrete rebar through the bottom of the post for a bit of extra holding power as an engineer suggested to me.

Cheers
Michael

[ThePope]

did you use steel or timber posts for the sail Michael.
Willo wants to use timber but I'm not too sure that's suitable for sails...

[mic-d]

did you use steel or timber posts for the sail Michael.
Willo wants to use timber but I'm not too sure that's suitable for sails...

I used gal steel posts. Recommended was 100x100 or 100mm diameter and 4mm wall thickness. When came time to buy them, the shade sail place talked me into 90mm diameter and 3mm wall and they turned out to be right, that's still a bloody sturdy post. As for timber, minimum post size recommended was 125mm diameter treated pine post. So a 125x125 f14 hardwood post might be OK.
Cheers
Michael

[Willo]

Hi,

Thanks- I've attached a sketch.

Yes, the deck is above (and forms) the carport and the sail (16sqm) will be above the deck. So the car willd drive under the deck into the 3m gap between the rows of posts. I was planning on timber posts- but would steel be better in the circumstances?

Cheers,
Willo

[ThePope]

1. I've read the span tables and would appreciate confirmation of the following:
Posts- 100x100 (what timber rating? F14?)
Ledger- 100x50 (what timber rating? f14?)

You're after second hand timber, I assume hardwood, so just about anything you get is going to be F14 or better. Softwood will hover around F7 mark.

2. With the joists, do I need 5.5 m lengths, or can I join two pieces above the bearers?

Always easier to work with full length timber where possible, a join is ok but full length is best.

3. Can I bolt the ledger straight through the existing "foreverboard" into the house joist, or should I cut it away? Will bolts every 500 be sufficient?

Bolts every 500 is fine, not need to cut away your cladding. Doing so would introduce water problems anyway.

4. Any suggestions to waterproof under the deck so the rain keeps off the car?

You could try screwing steel roofing or laserlite ect underneath the joists, but don't expect it to be fully waterproof.

5. If two of the outer posts extend 2.5m above the deck to hold a shade sail, will the footings of 300x300x450 be sufficient? I was planning on timber posts- but would steel be better in the circumstances?

Those sails place huge loads on whatever they're attached to, ask whoever is supplying the sail and see what they recommend for posts and footings.

[Willo]

Thanks again!

Leaving the sail issue to one side, can you please confirm that you think these dimmensions would be suitable for the deck as described:

Posts- 100x100 f14
Ledger- 100x50 f14
Bearers- 150 x 75 f14
joists- 150 x 50 f14 (450 centers, continuous spans of 2.5m, 3m)

Also- I thought I would get the concrete for the footings delivered- but am worried about setting the posts (and getting them square etc) quickly enough... What do you think is the best process for this?

Lastly, with the stairs against the existing wall, do I need an additional post against the wall to support the closest stringer, or is there a nifty way to attach it safely to the ledger?

Cheers,
Willo

[ThePope]

Yes all those timber sizes are fine.

If it were mine I'd be setting steel post shoes into the concrete and then bolting the timber posts to those.
Setup a few timber profiles/pegs outside the work area and use string lines to position the shoes.
Pour your footings and push the shoe into the concrete, hold the shoes in place with timber offcuts placed across the footing and under the shoe's base. Juggle the shoes around so they line up with the string line.
Do all the setting out, string lines ect before you concrete of course.

Change your ledger from 100x50 to 150x50 and attach joists to that using joists hangers, stair stringers are cut over the deck as drawn. As long as that ledger is fixed well to the house wall it will support the stairs without a post, but if you can get bolts/coach screws through the stringer into the house wall then do that also.