Building Homes or Extensions/ceiling joist

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Expert: - 4/16/2010


Question
I have a 21 foot span in my addition and I was going to use 2x8 for the span im wanting to use the attic space for limited storage.the spacing will be on 16 centers

Answer
Wes, this is a great calculator that lets you change lumber type and grade, loads, and spans:
http://www.awc.org/calculators/span/reversecalc/reversecalc.asp

Your 2x8's are not in the ball park.  This page:
http://www.awc.org/calculators/span/calc/timbercalcstyle.asp?species=Southern+Pi...

gives the maximum span on 2x8.  I used #2 grade SYP (southern yellow pine_ one of the strongest framing lumbers available.  I used 20lb live loading which would be extremely light storage - like the Xmas lights and the empty suitcases.  

You will not get a building permit with the sizes you indicate.

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Dan Griffin

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I can answer almost all questions related to the total construction process. My expertise is in commercial construction, though I can field most any residential question. I have hands on experience in concrete, heavy equipment, masonry, all phases of carpentry, interior finishes, and I am fairly strong in mechanical and electrical.

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I have over 20 years experience as a commercial carpenter and commercial construction superintendent. I have another 20 years experience in facility management for a major school district.

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