This sounds so familiar... Here's a story about my 1961 house that is built on concrete slabs.
About 18 months ago, we noticed a bit of the hardwood floor was bubbling up. We ignored it. About 6 months ago, our water pressure started to drop and then disappeared altogether. The plumber came and told us that our well pump (which was relatively new) wasn't working. They pulled the pump and the PVC bushing around it was cracked, so it had been running nonstop trying to keep pressure up. Plumbers fixed the crack, put the pump back in, it still wasn't working... They pulled it again and replaced it.
I mentioned to the plumber that the floor was bubbling up and he told me that what likely happened is that the supply line was leaking under the slab (where they put them in the 1960s), probably causing the floor to bubble and the well pump to turn on and off frequently, increasing torque on the bushing, which caused it to crack and subsequently burn out the motor. He referred me to a contracting group that could help with the problem under the slab.
Fast forward to June of this year. Contractors begin to pull up the wooden floor, only to find there's asbestos-laden linoleum under it. An asbestos remediation firm came and removed the entire wooden floor and the asbestos. (Note: the wooden floor was parquet, of a formerly-standard size that no longer is made, meaning to replace it and match the rest of the house, we would have to find somebody to cut each tiny little board.)
Early July, contractors jackhammer into the slab and cannot find a leak. While investigating, we discover that the septic tank is full and backed up, likely from some landscapers running over the septic field with a bobcat about 3 yrs ago. It had been slowly draining and we had it serviced 18 months ago, but it was again full and plumbers began to speculate that sewage was standing in the lines under the house and that an old septic line was leaking -- not the supply line. Nobody can figure out what to do because the original plans to the house are missing, the plans to an addition are missing, and nobody knows where the supply lines or septic really run, in spite of the fact they had snaked cameras through them 4 times.
Meanwhile, we have a huge hole with ragged pieces of rebar and concrete everywhere in our family room. My 2 and 4 yr old daughters learn to walk around it carefully because it's impossible to get to the kitchen without walking through the family room.
Plumbers come back 4 weeks later with a plan to replace the supply lines and the septic lines. We have to take a break to get insurance approval and take out a HELOC to cover costs that insurance won't cover. This takes a while.
Ten weeks after the first hole in the slab, they start digging to replace the septic/supply lines and they mistakenly break into the air ducts running under the slab (the fancy new thing to do in 1961). Surprise: the air ducts are made of a fibrous material that sort of looks like cardboard but might contain asbestos.
Today, the asbestos remediation people came and took a sample. The HVAC repair people (took 4 companies to find somebody to attempt to repair the 'cardboard' ducts) put a camera in them and found that the vibrations from the jackhammer used to cut the slab (likely) had caused many other collapses in the air ducts in the same room. The only saving grace here is that it appears that the 'cardboard' ducts only were used in that room and that they are metal in the rest of the house (please please please). Now, the demolition team has to come back and remove most of the rest of the slab in that room and in the kitchen in order to replace the 'cardboard' ducts that are collapsed; all prior to doing final repairs on the supply and septic lines running under the slab. When that's done, we'll have to repair the slab, get new floors, new kitchen countertops, and hope that we can move back in.
We've been in a hotel with our two daughters on-and-off for the past 3 months. I really hope we're in the house by Christmas.
Please be very careful if you purchase an old house.
Here are some pictures: http://imgur.com/a/JxiKl
FYI, ours is an old Westinghouse Total Electric Model Home (pdf): http://www.ncmodernist.org/westinghousehousebroch.pdf
p.s. That was way more than I intended to write here.
p.p.s. Total bill, to date is > $50k. Insurance is covering 95% of it. Amica is wonderful.