decking questions

[wjwren]

I wanted slabs but mrs over ruled so it's decking.

What thickness of decking board is recommended.
Softwood ok or hardwood
Best way to connect joists together? decking is 5.9m x 3.5.
Do I need joist hangers? Watched few videos on youtube some use them some dont.
Lastly what do I preserve it with - stain or oil and what is the best.

thanks

[Evanivitch]

Step 1 - Buy composite.

[wjwren]

id love to put too expensive.

[chockymonster]

wjwren said:

I wanted slabs but mrs over ruled so it's decking.

What thickness of decking board is recommended.
Softwood ok or hardwood
Best way to connect joists together? decking is 5.9m x 3.5.
Do I need joist hangers? Watched few videos on youtube some use them some dont.
Lastly what do I preserve it with - stain or oil and what is the best.

thanks

I'm using softwood, I'd have loved to use composite but 48 sq metres of deck board makes it a tad on the pricy side!
What do you mean by connecting joists? I'm using 6x2 c24 timber that's 6 metres long, you could use 4 metre joists or 6m, depends which way you lay them.

I have a ledger board at one end of my run, that will have joist hangers on it and I'm going to use owatrol products to keep it looking nice.

[wjwren]

ive heard owatrol are meant to be very good. Il have to see if I can get hold of 6 metre runs as the local place only did them up to 4.8, or il change the run direction.

[chockymonster]

wjwren said:

ive heard owatrol are meant to be very good. Il have to see if I can get hold of 6 metre runs as the local place only did them up to 4.8, or il change the run direction.

I've just had my timber delivered by Chiltern Timber.
8 3m 6x6 posts, 14 2x10 5.4m lengths and 35 2x6 6m lengths.
Pricing was cheaper than all of my local merchants.

[Davel]

Just in the process of replacing our old decking, which came with the house. It's pretty rotten and, shock horror, so is the frame underneath.

So we're looking at composite this time - but we need to cover about 150 sq.m.

Ouch!

[V8RX7]

You could use joist hangars but my carpenter tends to just sink two 6.0x100mm screws through the one into the end of the other.

It held up fine for the 8yrs we were there.

[wjwren]

it will be going up against the house so what is the best way to attach it to the house?
thanks

[V8RX7]

wjwren said:

it will be going up against the house so what is the best way to attach it to the house?
thanks

The best way (IMO) is to bolt a timber to the wall (with DPC between) and fix to that.

[AlmostUseful]

I bolted the ledger plate to the wall and then used joist hangers, I only did a few, and I found them pretty crap to be honest, so reinforced them with a load of 5" nails.

There were plenty of other places I could use joist hangers too, but I just used a 75mm screw to locate it and then put 5 or 6 of the 5" nails into it the joint to secure it.

[wolfracesonic]

For my 7''x 2'' deck joists I bolted a 9''x2'' ledger to the wall, packed off with some washers to allow water drain away; then fixed a 2''x 2'' to the bottom of it using polyurethane adhesive and heavy duty screws, sat the joists on that, then fixed noggins in between them to stop any twist, everything screwed to each other.

Edited by wolfracesonic on Thursday 30th June 08:00

[33q]

wolfracesonic said:

For my 7''x 2'' deck joists I bolted a 9''x2'' ledger to the wall, packed off with some washers to allow water drain away; then fixed a 2''x 2'' to the bottom of it using polyurethane adhesive and heavy duty screws, sat the joists on that, then fixed noggins in between them to stop any twist, everything screwed to each other.

Edited by wolfracesonic on Thursday 30th June 08:00

The trouble with this is that you get a nice flat surface for water to sit on and cause rot.

Better to attach a wall plate set off from the house ( like the washers idea, or use plastic packers, the ones that are U shaped). Build the deck frame just screwing through and then attach the deck to the wall plate

[wjwren]

So are joist hangers worth it or not!

What size or spec screws are recommended for joists?

Edited by wjwren on Thursday 30th June 10:08

[V8RX7]

wjwren said:

So are joist hangers worth it or not!

What size or spec screws are recommended for joists?

Internally - yes, mostly to stop squeaks.

Externally - I don't see the point most homes joists are held on 3x 6" nails - they do the job.

[wjwren]

How many screws for 20 sqm of decking - had quote off local merchant below. Surely I wont need 1200 screws?! Is 28mm thickness acceptable? Also 100mm on the joists or is 150mm recommended?
Comes to £480 inc the vat.
thanks

[chockymonster]

wjwren said:

How many screws for 20 sqm of decking - had quote off local merchant below. Surely I wont need 1200 screws?! Is 28mm thickness acceptable? Also 100mm on the joists or is 150mm recommended?
Comes to £480 inc the vat.
thanks

I'm only using screws on the deck boards, everything else is either coach bolts or sheradised twist nails.
As for deck boards screws, 230 sq foot of boards should be around 800 screws if you're going at 90 degrees to the joists, but it's never a problem having too many!

Just out of interest, how high off the ground is the deck going to be?

[WindyMills]

2no fixings at 450c/c, for a length of 3.5 = 16 fixings per run.
Approx 50no 120mm wide board = 800 fixings.
Plus any other trim, joints, etc. 1000 seems fine.

Total 26 joists, assume 2 fixings and both ends, = 104
Plus fixings to posts, poleplates, etc. 200 seems fine.

[wjwren]

It will be approx 6" off the floor

[sandman77]

wjwren said:

Also 100mm on the joists or is 150mm recommended?

What length are the joists? Anything over 3.5m and I would go with 150mm. It will stop the deck feeling springy.