Rounded Deck Framing Question

bruceerice

We're building a deck 24'X12' that has a rounded outside edge. The deck is about 6' off the ground and one side is against the house with the edge that is away from the house rounded at about 18" over the 24' span.

We are thinking about how to frame the outside edge. We feel confident that we can get the right support under the joists, but at the end of the joists do you think we should use some limber material like multiple layers of siding to make the curve.... any ideas?
thanks

neolitic

If you mean it deflects 18"
at the center of a 24' span,
you should be able to bend
a 2X that much with ease.
You could probably find one
at a box store already that crooked.

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BuiltByMAC

Cut your joist ends to follow the curve,
block between joist ends,
install 1x fascia over blocking and ends,
run your decking long over the fascia and mark decking ends w/ a jig that slides along the fascia,
Cut decking to match curve.

What are you doing for handrail?

Mac

neolitic

Mac, Your fir wouldn't make that
kind of bend?
I've done some a bit tighter than
18" in 24' with a YP 2X12 and it
worked pretty easy.
Tight ones I laminate a couple of 1X's.

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DecksEtc

I've done the framing as explained and then got myself a couple of sheets of 1/2" PT plywood and ripped it down to the right width. I laminated the plywood with a marine adhesive. 3 layers of the plywood got me up to the necessary 1 1/2" for the rim joist. My radius was quite a bit tighter than your 18" over 24' so that was my best option.

redwood

You don't specify what species of material you want to use for your rim joist/fascia. We usually use 2x12 redwood and I think that we could bend it to that radius. If not, we rip it into 2 pieces and glue it up.

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Quinn

18" in 24'? I would like to see a picture. Just doesn't seem like much of a bend.

BuiltByMAC

Probably...I was just bringing another option to the table.

Mac

neolitic

Just wondering.
Treated fir is a truly an
alien species to me.

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Stone Mountain

We have done several curved decks with a maximum curve or 2' out over 16'. This seems to be the natural limit of 2x pressure treated. In some instances, with a smaller radius, we've used flexible plywood (marvelous stuff) and then covered it with 1x6 verticals, radiused the deck boards to the curves, and then cut a 1/2 x 4 for a bullnose.

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bruceerice

My first time to use the site and thank you for all the valuable information. The floor joists for the deck are 2X12 so we are going to try to use 2X12. The tip about cutting the blocks should work well and I will find out soon if we can bend one to match the curve.

We are using those Simons deck clips DBT1Z that allow you to set the treads without screws. It's a a redwood deck and we just re-finished a deck that we installed about 4 years ago with the deck clips and they are still working well. The only problem is that they are expensive.
Thanks again

ScipioAfricanus

Another thing you can do is if the back side of the radius will not be seen I have run saw kerfs on the back side of a 2x for this kind application. I would say about every 6 in. maybe 1/2" to 5/8" deep. It really helps to make the bens a little easier.

Andy.

woodworkbykirk

sounds good to me!!!, did that on a deck 3 years ago this time of yea. it was interesting making it bend since the lumberyard keeps all its pt plywood outside, it was soaked then frozen soo..

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DecksEtc

This might be a little late but I was able to dig up a picture to show how I do this:

Attached Images

 

BreyerConstruct

Terry,

Have you been back to visit that deck? I'm wondering how the exposed end grain of the plywood has held up... I've considered this option, but haven't tried it this way yet.

Thanks,
~Matt

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DecksEtc

That was a progress pic Matt. I actually sealed the cut edges with preservative and then it was covered with 2x6 decking. Also, I faced it with 1x10 clear cedar.

BreyerConstruct

Sounds nice.

It's honestly prolly as good or better than slicing the back off of a 2x10, which just creates as many places for bugs & moisture to get into...

~Matt

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DecksEtc

Well there's nothing getting between those layers. Each layer of 1/2" ply was screwed to each joist and there is more than enough PL in between the layers - trust me

BreyerConstruct

Was the plywood difficult to bend for this curve? Did you use any moisture to soften the wood? Any significant creaks & cracks?

Sorry, always looking for w better way... and would like to try this out.
~Matt

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DecksEtc

The ply was pretty wet (just like any other PT we buy ) so I picked it up, took it to the site, ripped it down and put in on the same day. The total length of the rim joist on both sides was about 10'6" - which is why that piece of blocking is there. Once the first piece was PL'd and screwed to the joists, I just attached the following layers a joist at a time. I needed clamps when I got close to the ends and I staggered where vertical seams were.

I basically just figured this out as I went along. The inspector never questioned anything about it and it's held up perfectly.