Contractor Talk - Professional Construction and Remodeling Forum banner

1 - 20 of 47 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
I am re-decking with composite. This new layout has boards on diagonal. MFG requires joists at 12" min so I am dropping new joists in between existing.

The original deck is about 8 yrs old and all the PT has found its shrinkage. The new joists though have not. How would you hang these to get the truest surface over time? Hang new joists high and hope they shrink down to true or start true and hope the new doesn't pull down over time?

I'll be the first to admit exterior work is not my thing so any thoughts are appreciated.

Will
 

·
Registered
Joined
·
16,392 Posts
I find joist shrink anything from 1/8" to 1/2" sometimes 3/4". If it wS all from new I would set them all at the same height. I don't nail my joists until I have got the decking down as if there's a joist that shrinks a lot then I put composite wedges under the joist in the hanger. But that's Prob not gonna work in your situation. If you can leave the joist out for a week or 2 before installing then that's your best bet.
 

·
Deck Parts Retailer
Joined
·
3,108 Posts
I am re-decking with composite. This new layout has boards on diagonal. MFG requires joists at 12" min so I am dropping new joists in between existing.

The original deck is about 8 yrs old and all the PT has found its shrinkage. The new joists though have not. How would you hang these to get the truest surface over time? Hang new joists high and hope they shrink down to true or start true and hope the new doesn't pull down over time?

I'll be the first to admit exterior work is not my thing so any thoughts are appreciated.

Will
If you like to go to court, do as the customer wishes because they think the old frame is perfect and want to be cheap. Avoid such bs at all costs.

Draft a disclaimer that leaves you harmless for waviness of the new floor surface, also works to eliminate these issues.

Should you plane the new joists down to match the old, the new will shrink and create the same problem you first had in reverse.
 

·
always building
Joined
·
1,814 Posts
the only way is to sticker them, strap them, let them dry, install..... or do all new. I find that if you educate your client they will make the right choice. If however they are only thinking in terms of saving nickels over quality... its probably best to move on to your next job:thumbsup:
 

·
Box Builder
Joined
·
6,315 Posts
I have a slightly similar issue with a deck job coming up. Reskin an old portion of framing and add a new portion. I'm either going to set it 1/4-1/8 high or put the stock on stickers for a week. In your situation could you drop the joists into the hangers and screw the toenails in while you deck the framing or just leave the joists loose. Unscrew the joists after you deck. Let the deck sit for a month or two and then come back and toenail and shim the joists if needed in the hangers. Might be a bit squeaky until you get everything fastened off, but beats wavy.
 

·
Registered
Joined
·
753 Posts
If the customer wants you to use existing framing, I would just set the added joists in level and go with that.
It is what it is....
He will be fine with it.
He made the compromise and decision.
It's a cost and time factor thing to him, probably.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #9
Thanks all for comments. Owner wants deck to be and stay true. So all existing joists were pulled, flipped, trued and reinstalled at the required 12" on center. Additional joists that are needed are air drying before install. This should work out well.

Thanks again,
Will
 

·
Registered
Joined
·
16,392 Posts
Thanks all for comments. Owner wants deck to be and stay true. So all existing joists were pulled, flipped, trued and reinstalled at the required 12" on center. Additional joists that are needed are air drying before install. This should work out well.

Thanks again,
Will

for what joists cost should have put all new in when you pulled the old.
 

·
GC/carpenter
Joined
·
40,936 Posts
I am re-decking with composite. This new layout has boards on diagonal. MFG requires joists at 12" min so I am dropping new joists in between existing.

The original deck is about 8 yrs old and all the PT has found its shrinkage. The new joists though have not. How would you hang these to get the truest surface over time? Hang new joists high and hope they shrink down to true or start true and hope the new doesn't pull down over time?

I'll be the first to admit exterior work is not my thing so any thoughts are appreciated.

Will
I've told customers I will use old joists and then give them all new anyway and tell them no charge. They love it, I do this all the time. What is it, an extra 3 or 400 bucks? My average deck is about 25 - $30,000.00. It's really an irrelevant amount when you think about what headache it prevents.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #15
BCC... I used the old basically at your recommendation. You were 100% correct on the shrinkage of new boards. It's all over the place and I can't wait to nail off the joists as you do. Old boards aren't going to move....
 

·
Registered
Joined
·
16,392 Posts
BCC... I used the old basically at your recommendation. You were 100% correct on the shrinkage of new boards. It's all over the place and I can't wait to nail off the joists as you do. Old boards aren't going to move....

floating the new joist is handy because they will shrink no doubt and no matter how much they shrink it won't affect the flatness of the deck. I got a bunch to go around on my deck and shim. Some are no longer sitting in the hanger by almost 1/4-3/8". It's annoying having to do it like that but you know 100% you gonna have a dead flat surface.
 

·
Registered
Joined
·
16,392 Posts
BCC... I used the old basically at your recommendation. You were 100% correct on the shrinkage of new boards. It's all over the place and I can't wait to nail off the joists as you do. Old boards aren't going to move....

Here's an example. These 2 joists started off almost the same exact width before install. Left them floating until after install and went around and shimmed the gaps with composite shims. The one on the left shrunk a lot and the one on the right hardly any at all. If I didn't leave them floating 1 of 2 things would have happened.

1. Fasteners would have broke or pulled out when board shrunk

2. They would have held but pulled down decking with them

Either way over time the deck board would drop down to the lowest joist and looked wavy.

ImageUploadedByContractorTalk1433937762.039730.jpg
 

·
Talking Head
Joined
·
5,388 Posts
I've gone around a few weeks after framing and put hot dipped washers under some of the joists after they shrunk. It's pretty wild how much width they lose.
 
1 - 20 of 47 Posts
Top