Building Homes or Extensions/retro post & beam

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Expert: Ted Barnhill (Principal, Design45 LLC) - 9/7/2007


Question
I am retro post & beaming our home to give us an upstairs bedroom.
My post & beams are 8x8, I am planning on using 4x7x12 floor joist w/ full inch &1/4 hemlock flooring,
How far can I space my floor joist on center?
 thanks, Ron


Answer
I would generally suggest running your structural scheme by an engineer before proceeding.  Not only can you be certain that your assumptions are correct, but you may find that you were overbuilding, and can actually reduce in some areas.  

As for floor sheathing spans, you can find charts in the Residential Building Code (Table R503.1 in IRC2006, but this may not be in effect in your location).  You are probably in the 48" to 60" range, depending on the Fb of your lumber and other factors; ask your lumberyard for these specs or, again, talk with a local engineer.  Good luck!

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Ted Barnhill (Principal, Design45 LLC)

Expertise

I can answer questions about architectural design, how to work with a designer, and best construction practices for most trades. I specialize in cold-climate design (I'm in Minnesota), older home renovation, and energy-efficient/sustainable design.

Experience

As a Principal of Design45, I design and detail new homes and remodels. I am formally trained in architecture, but have also been a contractor and have experience with many trades. I strive to provide beautiful, durable, and efficient homes for clients and communities of all types and budgets.

Education/Credentials
Undergraduate work at Princeton University (Mathematics), Master's work at the University of Minnesota (Architecture)

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