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Load Bearing Wall - Beam size

Tristan's Avatar

Join Date: Jan 2013
Posts: 4

01-15-13, 10:25 AM   #1  
Load Bearing Wall - Beam size

I am knocking out an inside wall (with a doorway in it) that is load bearing. However, I'm having trouble finding the right answer to what size beam I will need to put in. I looked at the building code, but can't understand the size table. My job seems pretty straight forward- It is on my main floor (1 1/2 level house) the span of the beam will be 10' , there is no wall on the floor above it. So it is just supporting the upper level floor. The room above it is a spare bedroom, my beam will be supporting about 8'9'' of the floor joists in the room. I am fairly certain the 3 2X10's will be more than sufficient to carry the weight. With 2 2X6's on either side of it to support. Any thoughts would be appreciated!

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czizzi's Avatar
Forum Topic Moderator

Join Date: Jul 2007
Posts: 6,968

01-15-13, 06:33 PM   #2  
If it is load bearing, you will need a permit to remove and the authorities in charge will be able to advise. However, I am confused, you description does not sound like a load bearing wall to me. The wall is acting more as a floor stiffener in your case.

BridgeMan45's Avatar

Join Date: Oct 2011
Posts: 3,196

01-16-13, 12:02 PM   #3  
Three 2 x 10s, properly connected and supported by decent columns down to the foundation, have a combined section modulus (S) of 64.17 cu. in. Enough to resist an applied bending moment of 70,587 in.-lb. (5882 ft.-lb.). Which works out to resisting a total uniform load of about 470 lb. per linear foot of beam, based on M = w x L squared, divided by 8. If your total applied load is greater than that, you need a stronger beam--three 2 x 12s have an S of 94.92 cu. in. (almost 50% stronger).

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