No Vent In Attic

Problems when roof has no overhang.

No vent in attic.

Without baffles blinders that prevent outside air from crossing over the vent a ridge vent may create almost no ventilation at all. For proper ventilation it isn t enough for air to simply get into your attic. The design of many older houses omits eaves which maximizes the amount of sunlight. Too often mechanical ventilation ducts from bathrooms kitchens or laundry rooms deposit warm moist air into the attic instead of outside the building envelope.

This creates a natural air flow by drawing in the air from outside pushing it up and out through the vent at the top of the house. A combination of air sealing and insulating the attic floor while providing ventilation considerably reduces the potential for condensation as warm moist air is less likely to enter the space and condense on cold surfaces. Typically you would have a gable vent on each end of the attic. This negative pressure causes the vent to open and let in enough air to relieve the pressure.

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. Studor vents are a very popular kind of air admittance valve that works really well. Gable vents may circulate air through only a small percentage of your attic. If you re wondering how studor vents work after the toilet is flushed the water flows down the drain resulting in negative pressure.

This is called passive ventilation. Static roof line vents are effective for ventilation but generally aren t recommended due to issues with leaks.