Pipe bursting or re/splip-lining to replace sewer main
We recently had a bit of backup of some plumbing in our 80yo house, we had a local company come out to repair it as it seemed the plug was in the mainline from the house to the city sewer. We elected to go ahead and have a camera ran through the line to determine what the ultimate cause was, during home inspection it was also videoed and we were warned of a couple of roots.
The camera runs the length of the line without find a single tree root or a sign of any tree roots...however it did find separation of the cement pipe sections to the point that running a faucet didn't result in water actually making it to the sewer...meaning any "low flow" is eroding around the sewer line and further destabilizing it.
As it turns out, it the plug itself was just before a major drain line for the kitchen and a few other areas was plugged just before hitting the soil stack...but perhaps we were lucky to detect the mainline coming apart before our options of repair become limited.
So, the question at hand is do we go with pipe bursting or another technique to repair the sewer line. Trenching is essentially out of the question, as its a 7-9' deep run directly through our front yard with a ~5' wall at the sidewalk edge. Anything that requires an open trench is going to be outrageously complex and expensive. The length to be repaired is ~45-50 feet.
The company that we had come out prefers pipe bursting, they would hand dig 2 access holes at each end of the line. The end near the edge of the house where the cast iron to concrete transition occurs and the end in the right-of-way where the transition to the city's line occurs.
I've seen a few neighbors having their lines repaired with slip-lining.
We want a one-time solution, if we are spending the funds it needs to be the "best" approach. The pipe bursting method is ~$4k, which seems in line with the $60-80/foot guidelines I've found online. Is pipe bursting the best option or is there something else we should consider?
Lastly, financially its not the best time to be writing this big check (do these things ever happen at the "right" time?)...but I feel like we are now playing with a ticking time bomb, if the line completely fails we would have to look at a maybe $15k open trench project.
Any feedback or suggestions is greatly appreciated.