Expert: Bruce E. Johnson - 12/12/2008

Question
I am redesigning a residential house, and I want to open the floorplan on the main floor. This requires the removal of a wall that is a bearing wall for the parallel roof ridge above (and a single floor). Steel is the way to go, but I don't know the proper sizing. I'm fine with a post somewhere, but I'd rather not have two, which would be the case to keep a wood beam under 10 inches in depth. I am assuming a live load of 100psf, which might be overkill. With residential, it might be 60psf. I need clarification on that.

The span of the building (at the intended location of the beam) is 33' (x 28'), however there are existing vertical members that will remain to support a portion of the span, so at most, I need to span 18'. With a second post, I could reduce that to 11', but I'd rather not put in that second post in the near middle of the room.

Is a W8x18 a sufficient beam for an 18' span supporting one floor and roof above? Or is there a different size?

Thanks!

Answer
Hi Charlie, I'm not an engineer so all I can do is point in the right direction.  http://store.steelframingalliancestore.com/restbeandcot.html
When you search steel beam span tables on the internet the above website comes up.  Download the pdf file and you should be able to figure out what size beam you can use in your application.  At first blush I think the size beam you are suggesting is adequate.  Sincerly bruce e johnson