Bathroom Vent Leaving Building

Hello All,

I have a building where there is a bad moisture problem. There is mold/mildew that grows on the ceilings/windows in the winter time. There are two causes for this; 1. Wet Basement (foundation may need to be excavated, and/or interior footer drains installed), and 2. No vent in the bathrooms. I had a plumbing/heating company give me an estimate to install bathroom vents. It is a ranch home with a very small attic space. The guy gave told me he would run the vents out so that they came out of the bottom of the soffit.

Question: Will running the vents out of the bottom of the soffit cause the moisture to over time soften and rot the soffit out? Would it be a better idea to run the vent out the roof?

TIA,
Molo

I know my bathroom is vented this way. I think I have even seen it as an option on exhaust fan boxes. Seems like it's fine as long as your soffit is not blocked up with insulation etc.

Do it right, either run it out the roof, or the sidewall. Running it into the soffit is a hack - you want the moisture out of the house, not stuck anywhere in it.