Floor Joist Spans


  #1  
Old 01-05-08, 05:05 PM
J
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Floor Joist Spans

I am doing a total remodel of a 100+ year old house. This includes some new walls, and replacing or redoing all of the floors. This will be a rental when I am done, so I am trying to keep my costs down. That is why I am posting this question.

What can each of these joists safely span?
2"x8"?
2"x10"?
2"x12"?


What would you use for a 8' span if it will be under a bathroom?
 
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Old 01-05-08, 06:30 PM
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Check with your local Building Code office. Codes tend to vary from area to area. Any changes in structure will require a permit.
 
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Old 01-06-08, 07:00 AM
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You are only talking a little difference in price. I would go with larger rather than smaller, and I would go 12" centers if possible. That way, the extra load of a filled tub, tile, etc. can be carried. If it was just a regular room, a 2x8 would probably be fine.
 
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Old 01-09-08, 07:42 PM
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joist selection

Originally Posted by Jasonprox700
I am doing a total remodel of a 100+ year old house. This includes some new walls, and replacing or redoing all of the floors. This will be a rental when I am done, so I am trying to keep my costs down. That is why I am posting this question.

What can each of these joists safely span?
2"x8"?
2"x10"?
2"x12"?


What would you use for a 8' span if it will be under a bathroom?
you said the house is 100, but not if it was a single story, 2 story or more. each area/state has codes that must be adheared to. you could figure the live load on the house and that would tell you which to use. when in doubt, err on the side of safety. generally there should be a double(2) joist under the supporting sides of a tub. consider a large person and a tub full of water! that is a lot of weight. the spacing of the joists will also be a determining factor in the size of the joist.
 
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Old 01-14-08, 06:51 PM
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the American wood council has a VERY handy dandy span calculator found here:

http://www.awc.org/calculators/span/...rcalcstyle.asp

No. 2 grade Southern Pine is a good start for species and grade. code minimum deflection is typically L/360, but i would reccomend L/480. You should use 40 psf live load and 10 psf dead load for standard residential construction.
 
 

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