I found Chris from this forum, and it's a very professional job that Chris did for us. I feel I must give something back in terms of a review, as well as our lesson learned. Bottom-line is, trust this professional.
We had a squirrel in our attic. (It would turn out that 3 of our 6 roof vents were chewed open.) We called around for advice and quotes. We made a mistake - in hindsight - of hiring a roofer to replace all the roof vents with metal ones. We put a radio in the attic and played it loud for the whole day, banged around, and did most everything that we thought useful to ensure that there's nothing inside when the roofer replaced the roof vents.
That turned out to be a mistake. Overnight, the squirrel came back, and chewed a new hole around the rubber fitting of one of the pumbling exhaust pipes.
It was then that we realized we had to call in the professional. We called Chris. He's professional and courteous, and put us at ease from the start. He told us that it must be a nest inside that had the squirrel come back and work so hard to regain entry. He assured us that he would fix everything, and we would not have to hire any roofer. He would also provide us with a year's warranty.
Chris showed up 2 days later. He climbed up onto the roof, did a thorough inspection, replaced the rubber fittings of the other exhaust piples with sheet metal, and left a one-way trap door around the hole. He came back 2 weeks later to remove the trap door, and sealed the hole. Job well done!
What we learned from this experience is that we should have called a professional from the very beginning, rather than mugging around... Luckily, we found Chris who fixed the issue at the end.
Trust this guy. He knows the stuff. We have just recommended Chris to somebody who has the same problem.
Thanks Chris!