Bathroom-exhaust-fan-too-small, if the gap is really small; as in the drywall basically touches the sides of the fan housing, you're done. just put the fans face trim on, and enjoy. if you really want to, you could run a bead of silicone caulk around the housing.. Cool house inspired ideas - creative ideas for your dream home, new in the box - never been opened. bathroom exhaust fan. too small for what i had planned. 7 1/4 x 7 1/2