replacing main support beam
Hi I have recently seen a brownstone that I like a lot and I want to make an offer, however, I did some amateurish sleuthing in the basement and found that the main support beam is eroded about a foot away from the foundation and doesn’t make contact. It is being supported by a metal…
Hi
I have recently seen a brownstone that I like a lot and I want to make an offer, however, I did some amateurish sleuthing in the basement and found that the main support beam is eroded about a foot away from the foundation and doesn’t make contact. It is being supported by a metal pressure pole from the floor to the beam. I know very little about this stuff, but I am assuming the entire beam will need to be replaced. How much does replacing the main support beam cost?
Thanks!
Thanks for the comments!
I’m 5:57. I am not an engineer, but I am a contractor who’s replacing the beam in my own house right now. I am going to stick to discussing my house because I have seen my house and have not seen the OP’s.
My house weighs about 300,000lbs. It’s a three-floor brownstone.
And right now the back of my house is on lallycolumns because the main beam has been totally eroded by termites.
Here’s the way my house works, structurally. All my load-bearing walls are resting right on that beam, so that the load of the upper floors is being borne by the beam and the party walls, not the outside walls.
To simplify your beam: The beam bears the 300,000 (or whatever) pounds and transfers that load to your foundation and into the ground.
Your foundation is built for this kind of (compressive) load.
A pipe jack or lallycolumn, or a few, will take that load (say, in my case, roughly half of the 300,000 pounds), and take it to the floor. My basement has a thin concrete pad for a floor. So if I just left the column(s) there as a band-aid fix, I would eventually find that my floor will fail and then the pipe jack would, obviously, fail as well.
It would make sense, if I were going to have my house on jacks for awhile, to distribute the load by putting the columns on planks instead of directly on the floor (to lessen the stilletto heel effect).
I am sure that the party walls are taking some load in my house. But since the beam is rotten, doesn’t it make more sense to just think about it in terms of the beam carrying the entire load?
The structural engineer I am working with is looking at it that way, and I am glad. I want to live in a slightly overengineered house with some redundancy built into it.
8:46, why be a maverick about such a huge amount of weight and such a serious investment?
OK so the consensus here is that nobody here really knows without actually having seen the house… everybody’s an expert, right?
Get an engineer to look at the beam and they should be able to tell you what the deal is.
The word that jumps out at me in your post is “ERODED”. What is causing the “erosion”??? Termites? Bad carpentry? Global warming and rising tides?
Whether the entire beam needs to be replaced will depend on the condition of the rest of the beam (also pay attention to the joists). Beam repairs can be major and they can be minor, but just be careful the repairs won’t require disturbing other systems in the house. That is pretty much always major and expensive.
Are you kidding me? What does the house weigh?!? This depends on the number of floors! Is this 2, 3 or 4 stories? I think the point is that since it’s a brownstone, there are load bearing walls so all this weight isn’t being dropped on 1 little post. The upper floors are being transferred down through the walls, so it’s only the stability of the floor above the basement that’s in question. Duh.
8:46 wrote: “….but disagree with 5:57.A house does not weigh 300,000 tons (this is a gross exaggeration)”
The thing is, 5:57 wrote “300,000 POUNDS” which is right in the ballpark for the typical townhouse.
John Ife
Anon 5:31 has some good points, but disagree with 5:57. A house does not weigh 300,000 tons (this is a gross exaggeration), and even if it did, all this weight is not being directly transferred through this one beam down through the “stilletto” heel post. If the post is only 1 foot from the foundation wall it may or may not need to be braced, but it definitely doesn’t sound like thousands of $’s worth of work, maybe only a thousand since there’s already a post and you may want to have it additionally supported or fixed if it wasn’t correctly done. If the post is sitting on a flange or a plate (sure hope it is!), and the floor is concrete, it may not be a big deal. Do yourself a favor and go through this with your inspector since you should be having the house inspected anyway.
YES. Barring that, get a qualified inspector. it’l cost you ~$750 but given that you’re first time buyers, it could save you significantly more than that. Not that a bad structure is necessarily something you should be afraid of, just aware of as you go into a deal.
Thanks again for the advice! To divert on a tangent: would it be best to have a structural engineer take a look at the beam before making an offer (We’re first time buyers).
Having similar concerns as 5:31. Think of it this way: your house is something in the ballpark of 300,000 pounds.
Sure, the steel is strong, but if what’s *under* the steel (which, btw, is acting like a stilletto heel right now, taking all that weight and pushing it into an extremely small footprint) is not, then who cares?
Do yourself a favor. Talk to a structural engineer who knows brownstones.