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StructuralEng
StructuralEng, Consultant
Category: Structural Engineering
Satisfied Customers: 7325
Experience:  Structural Engineer
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I want span 21' floor joist with no beam below and no

Customer Question

I want span 21' floor joist with no beam below and no bearing walls above, want to keep the height of joist to minimum, what can I use in wood material?
Submitted: 2 years ago.
Category: Structural Engineering
Expert:  StructuralEng replied 2 years ago.

Hello. I can help

Expert:  StructuralEng replied 2 years ago.

Will they support any ceramic tile or other brittle floor finish?

Customer: replied 2 years ago.
3/4 toung and grouve ply and carpet
Expert:  StructuralEng replied 2 years ago.

Thank you. Give me a few minutes to run numbers

Expert:  StructuralEng replied 2 years ago.

3.5" x 9.5" 2.2E LVL at 12" on center is the most shallow you can go

Expert:  StructuralEng replied 2 years ago.

You do run the risk of walking induced vibration problems going that soft on such long floor joists, but they work for strength and deflection

Customer: replied 2 years ago.
can we do 16" on canter?
Expert:  StructuralEng replied 2 years ago.

It just barely works at 16" on center. It's right at the deflection limit and is more likely to be a problem for vibrations

Expert:  StructuralEng replied 2 years ago.

Hello. Do you have any other questions for me on this topic? If you could rate my answer, I would appreciate it.