# Overspanned?



## Keeyter (Sep 18, 2010)

Went to look at a second floor bathroom today. First thing that stood out was the in wall stand alone furnace. Home was built in 1919. HO want natural stone floors, walk in shower etc..... So I look at the second floor joists and they are 2x6 16OC spanned 14 Ft. There is also an attic above this second floor. 

Homeowners said the upstairs story at one point was a rental unit and before that they heard is was storage only. Back in the day did the builders overspan joists or rafters in this case and just use the area for storage or were the standards just lower. 

I am afraid we will be doing alot of Sisters (sometimes fun to do sisters), but with new cherry floors already....

Any thoughts


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## cleveman (Dec 28, 2007)

I've never done any sisters, so I can't comment on that. I've spanned 12' with 2x6's spaced every 12" and that was just fine. I put in blocking and it was good. If you want to span 14' with 16" spacing, I would just put them every 8" instead of sistering. This may actually be acceptable according to the span charts. If for some reason, you can't go 8" OC, then I would just sister by glueing and screwing on 3/4" plywood to each joist. And alternate the joints where the plywood sisters come together.

You're just engineering by the seat of your pants and you'll need an engineeer for a building permit, but we all know this will work if you don't need documentation.


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## ChrWright (Jul 17, 2007)

Keeyter said:


> Went to look at a second floor bathroom today. First thing that stood out was the in wall stand alone furnace. Home was built in 1919. HO want natural stone floors, walk in shower etc..... So I look at the second floor joists and they are 2x6 16OC spanned 14 Ft. There is also an attic above this second floor.
> 
> Homeowners said the upstairs story at one point was a rental unit and before that they heard is was storage only. Back in the day did the builders overspan joists or rafters in this case and just use the area for storage or were the standards just lower.
> 
> ...


It's definitely over-spanned and would not be sufficient even for ceramic tile:

http://www.johnbridge.com/vbulletin/deflecto.pl

That floor has to feel like a trampoline, and I don't think sisters would help. You would likely have to figure a way to cut the span somehow.


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## Keeyter (Sep 18, 2010)

The Ceiling below is Plaster Lathe and the bathroom is actually a part of a dormer if that changes things. Could add a beam somewhere but cost vs cost of opening a ceiling vs opening a floor...


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## superseal (Feb 4, 2009)

You need sisters and brothers, but preferably 2x10 or lvl's

And you ain't even near the ballpark for stone :no:


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## Keeyter (Sep 18, 2010)

superseal said:


> You need sisters and brothers, but preferably 2x10 or lvl's
> 
> And you ain't even near the ballpark for stone :no:


I know I would like 720 for stone, but I have what I have

I cant seem to find span tables for Brothers and sisters, whats the rule on doubling 2x or using ply.. Are there tables that I am missing


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## cleveman (Dec 28, 2007)

You can go 12' at 12" OC for standard framing.

Can you dig that?

But you want to go 14'? So double up your joists and go 14' at 8" oc. That shoould do you for stone. If it doesn't. then forget stone. It will do you for tile.


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## LEVELBEST (Dec 28, 2006)

cleveman said:


> I've never done any sisters, so I can't comment on that. .


I have, twice! Back in my younger, single days! As far as your question....I'll let a framer answer it, they wouldn't know anything about the other "doing sisters" part anyways. :w00t::w00t:


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## Keeyter (Sep 18, 2010)

cleveman said:


> You can go 12' at 12" OC for standard framing.
> 
> Can you dig that?
> 
> But you want to go 14'? So double up your joists and go 14' at 8" oc. That shoould do you for stone. If it doesn't. then forget stone. It will do you for tile.


It don't bother me what it ends up 14" or 2", the plumber may not like it but if its Structurally sound fine by me.

The Span as it is now if 14' from Inside to Inside of the outer wall and the second floor supporting beam. The beam splits the house in half, there could be option to add a beam (The bathroom is over another bathroom and kitchen) taking the span to little less than seven. The ceiling attached to the underside of the joist is plaster/lathe with new Sheetrock over it. My guess is that puts dead load over 10. Obviously sistering with 2x will be a challenge as well depending on how much electrical is in the way.

My biggest problem will be the inspector, is he going to make me sister the complete second story or can i get away with doing just the bathroom affected area. Does this span with live/dead loads dared be called in spec? The span tables I have dont show 8OC, do you have the data for that regarding deflection?


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## greg24k (May 19, 2007)

14' span you should have a minimum 2x8 DF lumber 16"OC... 2x6 what you have there now even at 12"OC the max span can be only 12" #2 DF lumber at 30lb LL for second floor.


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## cleveman (Dec 28, 2007)

Can you explain more about what is underneath? Sounds like if you have some supporting walls underneath, the situation may be taken care of.

Regarding the span charts, I would approach it this way:

Whatever you gain by going from 16" to 12" spacing (say 4' of span) you can gain the same amount by going from 12" to 8" spacing. Make sense?


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## Keeyter (Sep 18, 2010)

cleveman said:


> Can you explain more about what is underneath? Sounds like if you have some supporting walls underneath, the situation may be taken care of.
> 
> Regarding the span charts, I would approach it this way:
> 
> Whatever you gain by going from 16" to 12" spacing (say 4' of span) you can gain the same amount by going from 12" to 8" spacing. Make sense?



I add a drawing tomorrow


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## Bweikel (Feb 20, 2011)

If you are gonna sister or even add joist I think I would go with LVL your local lumber yard should have specs on the LVL joist. Maybe look on the i level web site.

That stones alot of weight I would over do it.


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## ChrWright (Jul 17, 2007)

Beyond a certain span, you will get diminishing returns on additional stiffness by sistering or reducing the spacing.

I think you'll find 2x6s won't be anywhere close to solid enough for even ceramic tile. Cutting the span will likely be your most efficient option.


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## Keeyter (Sep 18, 2010)

Thanks for the replies, I appreciate everyone's insight. My biggest hurdle is going to be the inspector, I have worked with him before and he is still at Woodstock. The problem is somedays he is a medicated and a joy to work with, others...Not so much. I am curious if any of you have had an inspector make you correct the entire floor. 

Basically what I mean is the area where the bathroom is only takes about 15% of the second floor area. From every number, reference, and research that I have done, and all of your input. I think the entire second floor joists are over spanned. I am nervous he will make me correct the entire story and all the joists. Have any of you had problems like this, is it common for most inspectors to what the whole floor done or just the area (bathroom in this case) that I touch.


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## Bweikel (Feb 20, 2011)

Keeyter said:


> Thanks for the replies, I appreciate everyone's insight. My biggest hurdle is going to be the inspector, I have worked with him before and he is still at Woodstock. The problem is somedays he is a medicated and a joy to work with, others...Not so much. I am curious if any of you have had an inspector make you correct the entire floor.
> 
> Basically what I mean is the area where the bathroom is only takes about 15% of the second floor area. From every number, reference, and research that I have done, and all of your input. I think the entire second floor joists are over spanned. I am nervous he will make me correct the entire story and all the joists. Have any of you had problems like this, is it common for most inspectors to what the whole floor done or just the area (bathroom in this case) that I touch.


If you haven't done any framing I would stop now and bring in a engineer to put his stamp on something. This could get ugly with out something on paper.


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## Keeyter (Sep 18, 2010)

Bweikel said:


> If you haven't done any framing I would stop now and bring in a engineer to put his stamp on something. This could get ugly with out something on paper.


Still in the estimate phase, just getting the ducks in a row so the homeowners don't have any surprises down the road.


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## Bweikel (Feb 20, 2011)

Keeyter said:


> Still in the estimate phase, just getting the ducks in a row so the homeowners don't have any surprises down the road.


I would bring in a engineer so you can accurately price the job not mention cover yourself of liability.

I would explain to the homeowner the situation in how adding any weight to a insufficient floor system could be dangerous and bringing in an engineer will waive liability of the ho and you for going forward with something that is clearly not structurally sound for the proposed situation.


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## cleveman (Dec 28, 2007)

I had a house (1 1/2 story work of the devil) where one half of the upstairs was framed with 2x6's 2' oc and the other half was just an attic framed with 2x4's spanning 24' believe it or not.

I ripped out the attic part and put a beam and hung 2x6's every 1' on the beam. The other area I put a beam underneath and added 2x6's to the 24" spacing, so they were 1' oc as well. So I was spanning 12' with 1' oc 2x6's. I put in some solid wood blocking i the middle of the span as well, denshield on the sheathing, then tile. No problems. Very solid floor.

I re-did the attic area with 2x6's because I wanted the floors to match up. My span chart shows you can span 12' with 2x6's 12" oc. Heck, you can span a certain distance with 2x4's at different spacing as well.

We put a rover on mars.


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