Bathroom Fan - No Vent

westgoin

We are attempting to replace a bathroom fan in a first floor bathroom (full bath) in a two story home. After removing the original fan motor and inspecting the fan housing we found there is no duct system connected and that the fan is venting directly into the space between the floors. While this is the least used bath of the home, I am very concerns about venting moisture directly between the floors! The fan may have originally vented to the side of the home, but previous owners constructed an addition that would blocked the venting area and do not appear to have compensated for venting. To complicate matters, we are sure the fan was installed with the original construction and is attached directly to the cieling beam with no easy access to remove without significant damage to the ceiling. There appears to be no logical path to vent to the exterior of the home without encountering major structural elements.

Any ideas out there on how to figure out a venting path? Does anyone know of any replacement fans that might have a recirculation feature for hard to vent areas that might work as well?

Michael Thomas

For starters:

IRC M1506.2 Recirculation of air. Exhaust air from bathrooms and toilet rooms shall not be recirculated within a residence or to another dwelling unit and shall be exhausted directly to the outdoors. Exhaust air from bathrooms and toilet rooms shall not discharge into an attic, crawl space or other areas inside the building.

Hard to give advice on routing duct without being there.

westgoin

We realize the vent has to be in accordance with code. If the venting was disconnected during the room addition as we suspect, it seems that the problem should have been caught in the local inspections, but that doesn't seem to be the case. May need to call in a professional on this one!

Michael Thomas

Generically speaking, one option is to use a remote fan that pulls air from the bathroom rather than pushing it out, that way your don' t have to be concerned with mounting a fan assembly anywhere in the bathroom, you just have a small grill over the end of the duct, and mount the fan in the attic or at the exterior:



Fantech is one manufacturer of such products.

Chemist1961

WG,
You mention the fan being mounted to a ceiling beam. I assume you mean a joist. Usually when you remove the grille of the fan you will see a set of screws or nails going sideways through the box into the floor joist in the ceiling above. Depending on the age and brand, if your fan motor is bad you may find a replaceemnt motor to fit., however this does not solve the vent problem.
I often run 2" rigid central vac pipe in walls in finished homes. While your vent pipe is larger, the principal is the same and I have a main floor half bath in my home with the same issue as you.
You need to try to determine your joist pattern in the ceiling and the look for walls in the bath which have your plumbing in them as an option. You will have a vent stack going up and a drain pipe or several dropping down. If you locate these they will be a start in finding a pathway for proper ventilation with hopefully minimal cutting. If you are really lucky you may have a pipe chase where several pipes and heat ducts run in a hollow wall pocket perhaps with your bathtub plumbing. Examine the room and walls /adjoining closets and post back more info ie bulkheads, etc.