Expert: Ted Barnhill (Principal, Design45 LLC) - 7/9/2008

Question
I would like to extend my kitchen which is about 35 feet long on the exterior wall size. I want to remove the existing exterior wall and create a opening with as little posts as possible. It will be replaced with a beam of some type I would guess. Ideally no posts at all. Above the kitchen/load bear wall is a family room and a bath room and of cause the roof. I am not looking at real numbers but before consulting an architect I would like to know if my idea is at all possible and what kind of material for the beam is recommended? Steal/wood. Oh my ceiling height is only 7' 8" so the beam can't take up to much space.

Answer
Steen,

You have an extraordinarily unique kitchen - 35 feet long and 7'-8" high!  

35 feet is a long span.  Unfortunately, it will not be possible to replace 35' of bearing wall with a clear-span beam as shallow as you you'd like.  Roughly speaking, for that span a laminated wood beam might be 3' deep, and a steel beam about 2' deep.  If you use at least one mid-span column, these depths can be halved.  In either case, it may be possible to insert the beam flush with the top of your ceiling joists, so that the exposed portion of the beam (below the ceiling) is perhaps 10"-12" less than the beam depth.  For example, with a mid-span column and an 18" flush wood beam, the bottom of the beam might be about 8" below the ceiling, or 7'-0".

For equal bearing capacity, a steel beam will be less deep than a comparable wood beam, but may create other challenges (wiring, bearing conditions, cost) that you and your designer must weigh.

I hope this helps - feel free to post a follow-up question if anything is unclear.  -Ted