joists and sub floor


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Old 08-12-08, 12:58 PM
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joists and sub floor

I am extending my second floor of a two story house over an existing open area to enlarge the gameroom. The existing second floor is built with 2x12 joists with 2x6 tongue and groove subfloor. The new room will be 12' x 15' and is well supported with a glu-lam beam and tied into the existing walls. My question is for the new floor that I am adding, which is a better way to go(sturdiest), continue with the 2x12 joists and 2x6 center-match #3 subfloor? or Use the engineered I-Joists and 7/8" OSB Decking? Thanks
 
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Old 08-12-08, 04:13 PM
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What is the joist spacing (existing & proposed)?

Are you running the 12' or 15' span?
 
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Old 08-12-08, 06:24 PM
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spacing

16" oc and the joists are running 12' span
 
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Old 08-13-08, 06:56 AM
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Assuming you have a simple span (i.e. "ballroom floor") with 40/10 loading...you shouldn't have deflection problems with 16"O.C. @ 12' with either 2X12 No.2 SYP or 11-7/8" PRI-20. If you are planning any heavy structures (arcade games, pinball machines, etc.) or walls (especially walls running along the joist length)...you might want to consider those added dead loads, although with the above joists you're pretty well oversized for that span.

While dimensional lumber strength is based solely on the wood's ability to resist bending, I-Joists have detailed specifications regarding attachments and subflooring that are important to their strength characteristics. Their ability to make longer spans with less material relies on these installation details. You may have already been here, but this is a great resource for PRIs (check out "APA Performance Rated I-Joists" .pdf)

http://www.apawood.org/level_c.cfm?c...ub_joi_libmain

Finally, make sure you carefully consider the load transfer to your glulam beam on the 15' run and how that load will be handled by the walls at the attachment points.

Good luck.
 
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Old 08-13-08, 07:00 AM
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Thanks

Thank you very much for your response
 
 

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