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Discussion Starter · #1 ·
I have a roof plan for a cut up roof but it is laid out on 24" centers. Do you guys frame rafters with 24" centers or 16" centers it is a 12/12 hip style roof with several of the common rafters at 28' long (10 of them) I will be using 2x12's to frame roof. Also do you put your ceiling joist on 24" also or 16"? Thanks for any help.
 

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I have a roof plan for a cut up roof but it is laid out on 24" centers. Do you guys frame rafters with 24" centers or 16" centers it is a 12/12 hip style roof with several of the common rafters at 28' long (10 of them) I will be using 2x12's to frame roof. Also do you put your ceiling joist on 24" also or 16"? Thanks for any help.
What will your roofing material be?

Asphalt? Tile? Slate?
 

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rafters and joist

your ceiling joist should be same as rafters. remember your rafters and joist should be sitting on your wall studs. so if your wall studs are 24" on center than your joist and rafters can be also. if wall studs are 16" than so should your rafters and joist.
 

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24" requires clips or thicker plywood. It's nice for fat guys to get through the rafters easily.

16" is what I grew up with and prefer. No clips, the plywood lays stiffer.

Check with your surrounding stick framers. Find out what is "the standard" is, and then build above that.
 
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Discussion Starter · #8 ·
I will go with 16" just the homeowner noticed on the plan 24" centers and thought I was overbuilding. But I will go with 16" as most do. Thanks to all the replies I appreciate professional opinions helps give one a good direction.
 

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If the plans call for 24" oc then that is how you should install the rafters. I would assume you bid the job based on the plans and specifications. If so by putting the rafters on 16" oc you are costing yourself money in both time and materials, not to mention legally you must do a change order whether you intend to charge for the difference or not. Just a tip: You should make yourself familiar with all the specs and drawings before bidding and refer back to them constantly while bidding any job that has them. You should also review them on the job at least once daily.
 

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Discussion Starter · #11 ·
So even if wall studs are at 16" centers still build the roof with 24"centers? The rafters will not land ontop of wall studs but it will have double top plate.
 

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Why in the world are you asking virtual strangers?

As they say in cards, who dealt this mess? Is there an architect? How about an engineer? How about a responsible building inspector? What about your local building code?

Roofs are framed at 24" centers in virtually every part of this huge country, from the deep snow country, down throught the great plains, into the deserts and river bottoms, hurricane country, earthquake country, and more. This, all atop bearing walls framed at 16" centers.

Here, with huge snow loads (90 psf at ground), roof framing is routinely done at 24" centers, and the sheathing is 5/8" OSB. And everything built here has to exhibit the wet seal of a NY state PE or architect.

You need a local pro to advise. Not someone from here.
 

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Regardless of how it is done and the location it is done in the approved plans and specifications are what you need to follow. If you question the spacing of the rafters do so to the person who specified it. Then if the spacing is changed do a change order and adjust your bid accordingly. It does not matter what anybody here or anywhere else has to say about the spacing. You have the approved documents in your hand and those are what you need to follow.
 

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Contractor?

So even if wall studs are at 16" centers still build the roof with 24"centers? The rafters will not land ontop of wall studs but it will have double top plate.
(Is this your first time?):shifty:

Read your framing specifications.

I agree, if you need to ask, ask a locally recognized expert, like the local building inspector or permitting authorithy. Either 24 or 16 centers on rafters is typical, or common practice. I prefer 16 on studs and joists with rafters at 24, joists stack next to studs and rafters stack directly over studs, 24 o.c. rafters stack over studs every other rafter layout, or 48" o.c.

I always layout studs under rafters, but not always on the same o.c. spacings.
 

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If it is my choice, I will go with 16" 90 percent of the time.
You can span farther without purlins.
You don't have to use clips on sheeting. Although I will use 2 clips on a sheet so you get the proper spacing.
No 'lateral support " between the joists and rafters needed.
 

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Discussion Starter · #16 ·
Thanks for all your responses all of you have a good point I will have a 18'6" horizontial span for the rafters and I will be using a 2x12x28 to get the length I need on several of the rafters that will run from ridge to outside wall plate. most of the others will cut into hip/valleys. I would rateher overbuild and be safe as to meet code and possibly have sags, dips, etc. You guys ever had any problems using 24" with 5/8 and clips?
 

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24" requires clips or thicker plywood. It's nice for fat guys to get through the rafters easily.

16" is what I grew up with and prefer. No clips, the plywood lays stiffer.

Check with your surrounding stick framers. Find out what is "the standard" is, and then build above that.
I use clips on 16 oc also. At least on the ends. It helps with keeping the plywood evenly spaced.

to the guy who said if your walls are 16, then your rafters should be too, what about trusses?? Cmon dude!
 

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I will go with 16" just the homeowner noticed on the plan 24" centers and thought I was overbuilding. But I will go with 16" as most do. Thanks to all the replies I appreciate professional opinions helps give one a good direction.
It's a Regional thing. We never frame rafters 24" centers. If your plans are drawn by anArchitect, why are you nopt following them and puttinmg them 24" centers? The day I get plans with rafters 24" centsres, that's when I'll frame 24" centers. I did get a plans 24" centers a couple years ago on an adsdition. Clips suck.If you frame 24" centers all the time, they probably don't suck.

Bottom line for you is if it's on the set of plans drawn by an Architect you have to follow them and can't change them unless the Archy agrees and signs off on them. Also as you've been told framing 24" centers is no problem anywhere so far.
 
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