so we hired another guy to fit a new liner, but it was beyond his abilities, so he took a loss on the deal and suggested we find someone w/ more experience. no money out of my pocket, so no biggie, but still a PITA as we still have a liner-less chimney and cold weather is fast approaching.
so i did some research and decided to DIY the flue-liner. but, of course, our flue was no ordinary flue, so i had to do my homework.
the total flue length from the basement to the top of the chimney is ~40'. that includes three (yes, 3!) ~90° dog-legs thru which the liner needs to be threaded. an appropriate length flue-liner costs upwards of $400 on the internet...that's just for materials, but i found one NOS/NIB on ebay with a BIN of $30...can you say "SOLD!"? i had to buy some assorted ductwork bits and stuff to get going, but we still saved alot of moolah.
when we started peeling the old flue liner out, we found a mess. it had deteriorated to the point where the metal would crumble to the touch. and it wasnt even installed correctly! there were actually two sections of flue-liner, but they werent even connected - with like a ~2' gap right in the middle of the chimney's length. our furnace is an older ~75% efficiency model, which crank out alot of moisture in their exhaust. literally gallons of condensation, getting dumped right into our brickwork FOR YEARS - this is BAD! and the old flue-cap wasnt sealed to keep moisture out, either. so we had moisture coming at us from all angles - no wonder the brickwork was crumbling before our eyes.
so, with all that in mind, we set out to install the new flue liner. i even got the ol' lady on the roof! we're happy now knowing that it's done RIGHT (even better than i would expect a typical contractor to do) and we managed to save a few shekels in the process.