Attic Ventilation Accomplished

Ideally we should have one square foot of Free Vent Area (FVA) per 150 square feet of attic floor space.  Half of this (FVA) should be provided by the ridge vents on the roof and the other half provided by soffit vents.  In the first two pictures you can see dark brown strips which are continuous vents.  Unfortunately, because of the large  gables on this house, there is insufficient linear feet of soffit to get the required number of vents.  Making the soffit vents larger could achieve the desired FVA, but we would not have the proper distribution of air flow around the house to properly cool the attic.  The third picture shows the solution to the problem.  An attic fan installed in the garage ceiling blows air into the attic space, enclosed by the knee walls, to pressurize that area.  Gaps in the insulation in the rafters at the soffits creates an air space which allows the air to flow up the rafters between the radiant barrier and the insulation and out the ridge vents.  The fan will operate off a thermostat and provides more air than would passively be provided by the correct soffit FVA.   Problem solved!