On 2005-11-11, Jim wrote:

I am in the process of deciding if I should just vent the fan into
the attic or cut a hole/holes in the soffit and have the ducting
terminate at this opening. One other option is to install a pvc T
fitting in an existing plumbing vent and have it vent through the
roof. Is the last method acceptable in most areas as far as the
building codes?

None of these methods is really acceptable. Venting into the attic is
right out, you need to remove the moisture from the house. I'm sure
venting into a plumbing vent is forbidden, you could conceivably get
sewer gases coming out the fan vent. Venting through the soffit is
allowed, but it is not really a good idea, because some of the
moisture will migrate back upwards, condense on the soffit, etc.

The two good options are (1) vent through the roof and (2) vent
through the sidewall, at least 3' below the soffit and at least 4'
horizontally from any operable windows.

Cheers, Wayne