Would you recommend replacing this lally column, which is located in the garage, supporting three bedrooms above?
There is heavy rust around the bottom, and it doesn't look like just on the surface. I used a hammer to tap the bottom of the column, and some rust came off immediately.... However, at this moment, I could not tell how thick the rust is.
Thanks so much for your comments!
This much rust damage is a concern. It's enough concern to make fixing this a high priority, take a look at it now, kind of concern.
I'd suggest calling a structural engineer to come out to take a look at this and have him recommend a solution. We have a very incomplete picture of the full situation, so anything any of us on the other side of the internet might suggest would be nothing more than random guesses. (We do have some engineers who hang out here, but with the info you've provided, even they would probably be just guessing.)
If it's going to be a few weeks before the SE can make it out, it may be worthwhile to get an adjustable lally column and set it up next to this one then screw it up into position, nice and snug.
It might be that the SE takes a look at the work you've done and decides that it's sufficient for a long-term fix, it might be that he recommends cutting this one out of the concrete and replacing it. In either case, it's his training, reputation, license and career on the line for the solution so he's going to guide you in the right direction.
Whatever he charges and whatever it costs to fix this will be cheaper than waiting for this to rust out and having the 3 bedrooms, their contents, and their occupants unexpectedly end up parked in the garage on top of the cars at 3am.
