This is a pretty common scenario I bet and how many others have been through this.
Cut a long story short we have a busted sewer pipe under the house slab/footings somewhere.
We had a conventional plumber come out a while ago, there was a blockage etc about 2m away that he fixed and created better flow but when he inserted an inflatable bag and we let her rip there was still water coming out from under the house slab (we dug a hole).
So that's where he stopped and said we'd have to bust up all the concrete. To the house wall is a 2' wide 1' thick concrete slab the previous owner poured (buggered of I know why). Plumber reckons bust that up from around the pipes then if needed tunnel under the house a bit!
Anyway, that's the history however talking to others apparently there's specialist pipe relining mobs around.
Yeah, like only 3 I could find, 2 did not return calls and of those 2 one when I rang them said they dont do pipes under 100mm dia. As these aren't sewer per se but sink/shower looks like 90mm.
That left only 1 company, out of all those plumbers etc, one company that I had to hunt down that might be able to help without busting up slabs and tunneling under houses.
They claim to be able to reline anything down to 30mm dia.
What a monopoly eh, first charge is like $275 for a camera inspection to see if they can do the job then a minimum $1500 to reline the damaged section.
http://www.nuflowtech.com.au/index.php
Man, are we in the wrong job. I get people want palms cut/dumped and stumps ground out for $100! I bet their investment into equipment is nowhere near the same as ours and their risks way lower. I foolishly did a phone quote yesterday where a guy wanted a palm cut down at his business rental premises, failed to show for the quote so I rang him, told him $220, he scoffed and said he'd have to think about it.