Author Topic: 20x30 2-story  (Read 3350 times)

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rdzone

  • Guest
20x30 2-story
« on: March 20, 2006, 08:04:19 AM »
John,

I am still in the planning phase for building and I have been trying to find a local source for I joists.  I was looking and the the plans and I think you spec'd TJI 250 Pro joists (11 7/8")  for the first and Second floors.  I went to TJI's website and I don't see them listed.  Is there another joist I can use.  Locally they carry TJI's, but is there another TJI product I can subsitute?  I want to be able to single span for both floors. that way I can put the walls where my Wife wants them.

Would it be worth upgrading to a 14" or 16" joist to help eliminate bounce?  I looked at TJI brochure and wondered if a TJI 230 16" would be a good choice. I don't mind spending a little more now to help minimize future precieve problems later.  Any info would be greatly appreciated.  Thanks.

Chuck

jraabe

  • Guest
Re: 20x30 2-story
« Reply #1 on: March 21, 2006, 06:37:22 AM »
Chuck:

It appears you are right. TJI has changed their criteria, numbering system and span tables once again.

The framing plan for the engineered joists (p. 10 in your plan set) has as an alternative of a GPI-40 of the same size. The Georgia Pacific joists may be more available where you are and GP tends to stick with their product line longer than TJI. Your supplier can make substitutions if you have other products in your area.

For a low deflection (bounce) in the floor you want to use a span table for "improved performance" (L/480). The first floor live load is 40 psf and the upper 30.

According to the new TJI chart their new 230 joist will span 19' -2" - which is just barely enough. (Span is the unsupported length not the total length. With two plates of 5.5" the actual span of the floor joists are 19'-1") You will note that there is no question of strength with this span and that it exceeds the code required L/360 deflection. To be cautious, however and reduce any chance of complaints, I would go with the TJI-360 @16" for the main floor and the 230 joists on the upper. The 250 was a better fit, but apparently no longer being made.

TJI charts
GP Charts
« Last Edit: March 21, 2006, 06:50:10 AM by jraabe »


rdzone

  • Guest
Re: 20x30 2-story
« Reply #2 on: March 21, 2006, 07:15:30 AM »
John,

Thanks for the reply.  My local distributor only carries TJI, so I will go with your suggestions.  When I called them they wanted the specs from the plans when I told them TJI 250,  they said no such number and that they wouldn't substitue I needed to get the new specs from the designer.  Thanks again.


jraabe

  • Guest
Re: 20x30 2-story
« Reply #3 on: March 21, 2006, 09:39:23 AM »
Interesting, a rather helpful supplier  :D.

Good at CYA at any rate!

(Probably need to blame the lawyers on this one)

 

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