Roof ventilation, in most instances, promotes air circulation throughout buildings contributing to healthy indoor environments and preventing material damage that can occur when warm, moist, air is trapped inside. Attic insulation is another component that creates comfort in controlling indoor conditions. More is not always better, more can be too much.
Recently, we have worked remediating building attics where excessive insulation has been installed in attic spaces, blocking attic ventilation, and preventing air circulation necessary for comfortable indoor living. Maine has had programs in place offering rebates and financial assistance for weatherization programs. The key, to making good use of the grants and low interest financing available, is hiring a reputable, qualified firm to complete improvements. Prior to hiring contractors to complete weatherization/winterization projects, ask for references, proof of insurance, proof of applicable certifications and check the Better Business Bureau for complaints. The following links provide basic information on attic ventilation published by energystar.gov and a reference manual published jointly by the U.S. Department of Housing and Urban Development and the U.S. Department of Health and Human Services.