Even for the second story bathroom you can access the attic to vent the moisture outside.
Venting attic with no soffit access.
The total venting space should equal 1 150 of the floor space.
In an attic without soffit vents you can add insulation in the corners and the wedges between the slope of the roof and the floor of the attic which serves as the ceiling for the room below.
Place all the roof vents on the same side of the roof.
If your roof peak runs parallel to the street put them on the backside where they ll be less prominent.
When hot air rises up through the soffit venting it then keeps rising all the way up to the ridge vent.
Mark the roof venting locations from the attic where you can see the rafters and avoid placing roofing vents over them.
Avoiding bends in the hose.
If the attic is insulated with fiberglass batts just pull back any that are blocking the flow of air.
The most common way to add ventilation to an attic is by installing air intakes in the soffits and putting an outlet at the gable of the house.
Now that we have that out of the way let s get to the heart of the matter venting a house with little to no eaves or soffits.
A soffit exhaust vent cover is installed in a straight line as much as possible from the bathroom exhaust fan.
The soffit vents are now installed but you still need to make sure there s no insulation blocking the new vents.
Unless your roofing system has insulation on the roofing deck and is designed without ventilation your furnace should not be heating your attic.
When the attic becomes part of the home to be heated and cooled open wall gable vents and roof vents are no longer feasible but the underside of the roof the sheathing and rafters can still get.
This creates a natural suction phenomenon where the ridge vent is sucking air out of the soffit vents creating a natural ventilation cycle.
A passive ventilation system should have air inlets at the base of the roof usually in the soffits and outlets in the peak or gables.
If you have an attic with no soffit vents but 2 unobstructed gable vents then you will probably be ok on ventilation.
How to vent a bathroom fan through soffit.
Normal vented air likes to enter the attic lower down near the bottom third of the attic and as it passes through it will exit higher up near the top third of the attic space.