Re: Bathroom Vent
Generally it's recommended that 1 CFM of exhaust for every square foot of bathroom. Also if the bathroom has a toilet and a tub/shower 50 CFM is recommended for each fixture. So basically an exhaust fan rated at a minimum of 100 CFM should be used in a regular bathroom.
Ensure the exhaust fan has at least 4 inch provision for ducting , the larger the better for longer runs.
I highly recommend using metal ducting and seal the joints with foil duct tape also cover with dust insulation... don't use the cheap white plastic flex duct.
Try and avoid hard 90 degree transitions .... make them as gradual as possible.
You're correct with sloping the duct ..... have it slope toward the gable vent.
Hope this helps.
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