Building Homes or Extensions/Vented Soffits under 2nd floor room eaves
I recently purchased a 50 y.o. house near Pittsburgh. The master bedroom is located above the garage as is the attached bath. The bedroom room and bath extend about a foot out from the garage and the eaves have vented soffit.
I noticed that the previous owner had cut some 3" holes in the garage ceiling under the bathroom and near the garage doors. Since the bathroom floor was cold, I covered those holes. The pipes to the bathroom promptly froze and that's when I noticed that the soffit was vented.
That space (the bedroom floor joists) is filled with batt insulation but I could feel air blowing up from the soffit when I checked out the pipes.
Do these eaves need ventilated soffits? This isn't like an attic that you need to vent. The garage is slightly heated (enough to keep it in the 40s and 50s). There's no laundry or sink there as a source of moisture (although snow melting off the car certainly is a source.)
I think that these vents only contribute to my cold bedroom floors.
The soffits should be ventilated to prevent mold and to stop any wood from rotting. But, if the weather is below freezing, like it has been most of this winter, then you can cover the vents until the weather stays above freezing. Did blocking the holes in the garage ceiling help keep it warm? As far as the batt insulation, if it were just laid in there, then you will feel some cold air getting in between the floor joists and the side of the insulation. There is an inch paper flap on most batt insulation that should be stapled to the floor joists to close the gap and make it more air tight. You are trying to keep the bathroom floor from getting to cold in the winter? If you are looking to do that, there are several ways to do that.