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Discussion Starter #1
The common 'clear span' my I-Joists claim is 19'8" on 16" O.C. - I have seen 18'6" to 20' be the normal rating depending on manufacture. These clear spans consist of no support below them, so although that is the max clear span, does the floor above feel spongy or sag any or are there supposed to be a certain series of tests they rate the I-Joist on that includes a solid floor up to that point?
 

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Tileguy
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6,050 Posts
There are several brands of engineered joists and each make dozens of styles for any span and load requirements you may need.

I have found that I-joists are usually spec'd at L480 for residential. You need to determine your requirement then consult the manufacturer for their recommendation. They'l need to know what the use of the floor will entail and type of flooring planned, etc.

Jaz
 

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Remodel and New Build GC
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9,461 Posts
Deflection or L rateing is a measure some times referred to as just floor performance. Every floor has some deflection... what feels spongy to one person may be satisfactory to another.

As a manufactured/tested product, you will find detailed charts as to TJ's L rateing for various spans /spacing /loads.

I believe code standards are L360 minimum.... but you can design what you want. I think Jazz probably wants L480 for tile (not sure) but you might want to firm the floor right up to L720 (whih is pretty much a good/great floor performance
 
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