Bathroom Exhaust Fan - Soffit Clearance from Window

[Marissa Taylor]

I recently had a ceiling bathroom exhaust fan installed and it is time to install the vent duct. I don't want it to exhaust into the attic so would prefer to have it exit the house via under the soffit. (Cutting through the roof is a no-go and there is no other surface available.)

I plan to run the duct right to the soffit inside the same joists that the fan is in. This would place the soffit vent outside the bathroom window. There really isn't any clearance to put it anywhere else.

Are there any restrictions/codes that would prevent a soffit vent from being installed outside the bathroom window? Since I don't open the top half of the double hung window there is almost no possibility of the exhaust re-entering the house through the window.

Also what is a good product to use for the soffit vent? I want something white, mostly flush, and with a back draft flap although my Panasonic fan also includes another snap.

Thanks!

[Joe]

Why? It's done all the time very successfully. Would it be visible from the street?

What did city hall say when you asked them? They have the code books right at their desk.

There are many choices in vinyl and aluminum. Lumber yards, box stores come to mind. Look for possibolities in the dryer vent section. IIRC, the sizes are both 4".

Joe

[SteveBell]

Some areas, Dallas for instance, prohibit soffit openings within four feet of windows or doors. In case of a fire, this keeps flames from going directly into the attic. I hear that California prohibits soffit openings completely, at least in some areas, because of brush fires. I hear they allow them with special self-closing louvers.

Check with the code office.

[HeyBub]

I'll bet the reason your bathroom didn't COME with a vent is probably because it has a window! My house has two baths - one abuts the exterior wall and one in the center of the house. The center bath has an exhaust fan; the other has a window and no fan.

That said, since you'll probably not have both the window open and the fan on simultaneously, I can't see what difference it makes for ventilation purposes. Fire safety and appeasing the troglodytes in the city permit department are other considerations.

And, yes, there are self-closing soffit vents. Here's one: