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floor joist spacing and size

9.5K views 35 replies 8 participants last post by  ProWallGuy  
#1 ·
My brother just bought a house that was built in the late 1800s and is compleetly remodeling it. The second story floor joist were sagging about 3 inches in the center of a 14'x18' room and the inspector told him he would have to install 2x10s on 8 inch centers. I'm thinking this is a little overkill but this isn't my line of work so I wanted to ask others who might know. What is the typical size limber used for this span(14') and what spacing is used. There is going to be a bathroom on this floor if that makes a difference.

I'm just a remodeler (flooring, painting, some finish work, exc.) so This is a little out of my league but I would think 2x10s on 12" or 2x12s on 16" centers would be plenty.
 
#3 ·
mikesewell said:
Show the inspector the span tables in your code book.
He did that but his code book is from 1998. The inspector told him his book was out of date and the code had changed but didn't offer proof from a more current book. My brother isn't a contractor so he didn't want to invest in all new and current books(I don't have them either because I don't do work on that scale). I guess what I'm asking is does this sound right or should he invest in a newer book and prove the inspector wrong. The savings in lumber would pay for the book if he was right. Also, does anyone have a link to where he could purchase code books? Thanks for any help you have to offer.

The house is in macon georgia.
 
#4 ·
That one would be new to me. How ever over 13' 7" I believe for No.2 or better is 12" on center. Select lumber you probably could go 16" on center.

Try google for the code books but expext to pay around seventy dollars. Make sure he gets the ICBO book.
 
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#6 ·
Rusty Nails said:
He IS tearing out the old ones, right?

He has already taken out the old ones and the roof is being supported by jacks. He will be putting in new ones this weekend. I'll see if i can get a newer code book from one of the GCs at a job I'm currently working to look at. Thanks for the examples.
 
#8 ·
mighty anvil said:
For dimensioned lumber (2x8 thru 2x12) @ 16" o.c. (not 12" o.c. which is not a good idea when trying to limit bounce) for ALL floors the following methods give the same results:
Say what?? Have you ever walked on a 12" o.c. floor let alone a 8" o.c. I have never had bounce with those oc's
 
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#10 ·
mighty anvil said:
It is always better, in terms of bounce avoidance, to go to a deeper joist rather than to go to a closer spacing. It should only be done when a deeper joist is not possible.

I have had plans that spanned 2x12's 20 feet and those had to be 12" oc I don't think there was any bounce. My deck out back is 24" oc and that mofo has some bounce.
 
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#19 ·
You gave me. You ever heard of google or do you work for awc?
Your the one trying to convince me you get less bounce with 16" oc. I am still not convinced. Considering even the 2x6 floors I built were L480
 
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#22 ·
Mighty Anvil riddle me this what do you do when you have a 25-26 ft building height and you need a min of a 6/12 roof pitch for snow load?

psst 2x6 crawler


Also it's not more money and time it's about more room. And the 8"oc (first floor)is about a piont load that carry's up to roof girder.
 
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#23 ·
NO 2x6 12"oc beam run every 4-5 feet. Also local code doesn't allow for 2x8 joists to be used unless it's a variance. 2x10 or bigger

Even tgi's oc's were shrunk to 16 oc instead on 19.2. I have even put them 12" oc. One of the local B.I.'s is a couple credits short from being a Engineer. Talk about a hard ass. But he has never failed my work. Unlike alot of framer's I know that want to maim him.
 
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#25 · (Edited)
mighty anvil said:
I have no idea what you are talking about and I suspect you don't either. Just give it a rest.

No you don't. And you don't build over here. I haven't done a 2x8 floor in years let alone a 2x6 unless there are height restriction.

I know it is easy being smart with cut and paste but you should give it a rest.

And actually since the state upped the R values for housing all joist are to be 2x10 or bigger and all wall studs are to be 2X6 vaulted rafter 2x12.


Do you want to play some more? I have a crate of old blue prints I can send you for review then you can call the architect's and engineers and tell them how smart you are and they don't know chit.
 
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