# Can a load bearing beam be offset from lapping joists?

I'm replacing a section of 4'' load bearing wall by a large 8''x8'' steel beam, and due to the size of the beam it would stick out to one side too much if I were to install it exactly centered with the current wall. I would need to offset it by about 3 inches to keep one side of the beam flush with the remaining section of wall. The joists above are lapped. Is this possible or the beam has to be absolutely centered with the existing wall?

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What is directly above the wall? If there's another wall above it transferring point to point load, you would be changing the angle of force involved, which should be structurally reviewed by an engineer. – The Evil Greebo Oct 7 '11 at 14:29
@TheEvilGreebo: Above the current wall I have another wall. But is it load-bearing that I don't know. I would say that it's not, because the roof rafters are parallel to these 2 walls. But yeah it looks like I might have to hire an engineer. – md1337 Oct 7 '11 at 18:22

## 1 Answer

You've essentially got a column buckling problem here. Factors affecting the maximum load include the geometry of the beam cross section, its material properties, and the manner which its ends are constrained. You can read up on it here.

What makes it more complicated is a possible eccentric loading condition, as The Evil Greebo points out. Now you have to worry about compressive stress and normal stress. This eBook does a good job describing the loading conditions and resulting stress under the "Maximum Stress" section.

Since the current exact loading conditions are unknown, and in addition you're changing the location the load is applied in, I think it would seek professional engineering advice. (I would, and I'm a mechanical engineer - I just don't specialize in architecture.) Either that, or an experienced contractor may be able to give you a better answer. (Shirlock, where are you on this one, buddy?)

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...and I just realized you're most likely talking about a horizontal beam rather than a vertical column. In that case, you can strike most of what I just said. – Doresoom Oct 7 '11 at 15:24
It took me a while to figure out what you were talking about. Yes I had a horizontal beam in mind, not a post. There will be posts to hold that beam up tho. – md1337 Oct 7 '11 at 18:27