[n0c7]

I need to install a bathroom fan and duct in my basement. The vent is already roughed in so I just need to attach ducting from the vent to the fan.

What type of duct material works best for this? Rigid, semi-rigid, flexible, insulated, foil tape vs screws for connections? I've heard some people add a "P" trap dip for moisture. Not sure if this if necessary especially since the clearance is only the space in the joists.

 

[hvac benny]

Use rigid duct, 30 gauge, tape or screws, or both. I prefer using both, but as long as your connections are good, tape doesn't make much of a difference. Insulation is only needed if going through a cold zone, but since it's in the basement I'd assume the duct will be between floors. No p trap, I've never even heard of that.

 

[Beepster]

I know here in Minnesota we need to have insulated wrap 3' in from the rim joist. I just buy the flexi duct that is wrapped with insulation and pull it out and slide over solid pipe Benny recommended. No trap, if condensation, moisture needs to drain in or out. So no dips either.

B

 

[jagans]

Duct

I think you should use PVC pipe, 3 or 4 inch attached to fan with a fernco fitting, and slope it to drain outside with a street el facing down at its terminus outside. Foam around the pipe on the inside of your house to block air infiltration, seal around the outside with sealant, and make sure the fan has a flapper valve. I just fixed two fans with corrugated aluminum flex, hot moist air was condensing inside and dripping from the ceiling. You dont trap fans. How would they work?

 

[rtoni]

I think you should use PVC pipe, 3 or 4 inch attached to fan with a fernco fitting, and slope it to drain outside with a street el facing down at its terminus outside. Foam around the pipe on the inside of your house to block air infiltration, seal around the outside with sealant, and make sure the fan has a flapper valve. I just fixed two fans with corrugated aluminum flex, hot moist air was condensing inside and dripping from the ceiling. You dont trap fans. How would they work?

jagans - i looked at the 4" fernco to do this on my fan - it seems like it's "somewhat" too large (inside diameter) to properly clamp / tighten around the outside of the plastic fan fitting. Is this (the standard 4" fernco) what you used? thanks for any add'l information