"Walter Cohen" wrote in message
...
Due to logistical reasons in my attic I need to route the new bathroom fan
exhaust duct up through the roof instead of out the side wall. It's also
a shorter run if I go vertically instead of horizontally.
I'll be buying 4" aluminum ducting so when I buy a hole saw to cut the
roof hole do I buy one that's 4" round, 4 1/4", or 4 1/2"?

Anything else I should do or watch out for?



I use a 4 1/4" hole saw in my angle drill at slow speed. You don't want to
go too fast with a puppy this big.