Span of floor joists

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Old 12-20-07, 08:25 PM
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Span of floor joists

How far can floor joists span without support? I'm looking at a 30' by 30' room and would prefer not to have an entire load bearding wall. Would a few support posts adequately provide the necessary support? Bedrooms and a bathroom will be above it.
 
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Old 12-21-07, 04:50 AM
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BT:

You need to consult a structural engineer. "Standard" framing comes in lengths up to 16', so that's out. (Longer lengths are available but they won't pass code unsupported.)

My company manufacturers floor trusses, but a 28' span is the max for our product.

If this is new construction, an LVL beam (post supported) may pass to hold standard floor joists, but again, you need to consult an engineer as well as checking code specifications for your area.
 
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Old 12-21-07, 08:49 AM
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George,

How do the cost and quality of floor trusses compare to one framing it out himself? I might be able to get away with 28'.
 
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Old 12-21-07, 11:55 AM
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Floor trusses engineered for a specific span and installed according to directions will be warranteed for the job.

They will cost more (material wise) than standard framing.

A local manufacturer may be able to span 30'.
 
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Old 12-21-07, 03:14 PM
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BTGrady - Are you building or renovating? I used I joists to span 24' in a garage. The joists were sized by a local lumber supplier. I installed them myself - literally. They were surprisingly light and easy to install.
 
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Old 12-21-07, 05:46 PM
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cwbuff, I am building. There is a lumber yard in town that I can ask.


George, do you know of any truss manufacturers in Arkansas?
 
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Old 12-22-07, 05:15 AM
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CW:

I -joists may be the answer - or LVL's. Height would be a consideration to span 30'

Meanwhile, here's a link to a listing of truss manufacturers.


http://www.thomasnet.com/arkansas/fl...8320502-1.html
 
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Old 12-22-07, 10:02 AM
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Height is a definite consideration. I had to go with 14" I joists when the original plans called for 2X8's supported mid span by a built up girder/posts. I ended up with unobstructed car bays and a very stiff floor for my workshop.
 
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