Taking Out a Wall, Installing a Beam
LESLIE: On our way to Texas now. Steve, what are you working on?
STEVE: I’ve got about a 24-foot span that I’m wanting to take a wall out and was wondering how big a beam do I need to support that much weight. It’s a one-story house built in the 50s and it has a – it’s on a slab. It’s a foundation but it has a subfloor in it. Back then, they put 2x4s kind of into a black tar type of deal …
STEVE: … with plywood over the top of that.
TOM: So, there’s a slab foundation but then there’s wood on top of the floor? Is this wall that you want to take out a bearing wall?
TOM: Then I think you need a big honking beam there. Probably what you’re going to need is a steel I beam. And the specific answer to what size beam that you has to – that you need for that, is going to come from the span tables of a code book. And it’s not something that I can give you verbatim over the phone, but I will tell you that with that level of span, that’s an awfully long span and I can’t imagine that any wood beam or a wood beam with a metal flinch plate that’s like sandwiched in between is going to be strong enough for that.
The other important thing to consider here, Steve, is where that beam is bearing. The ends of that beam – whereas right now the wall may be supported by a continuous footing under that whole space, if now you’re going to point load all of that weight just on the two ends of the beam, then that area has to be strong enough to handle that because the weight’s going to come down the beam, go across, then be distributed down to the columns. So you have to have a substantial foundation to be able to support that.
So the specific answer is going to be determined by consulting the spanning tables in the code books. And if you don’t have one, you can get one at the local building department or you can consult an architect or engineer or even the manufacturers for these beams will be able to tell you what they’re rated for. But I don’t think you’ll be able to do it with a wood beam.
Steve, thanks so much for calling us at 888-MONEY-PIT.