Attic Ventilation – Ridge and Soffit Vents
DEAR TIM: Yesterday afternoon, I went up into my attic to retrieve an old book. It was so hot that I became dizzy and almost passed out. The 3 square metal vents in my roof were not clogged. The air was stagnant. Should I improve my attic ventilation? Is it necessary? F. B.
DEAR F. B.: You're lucky you made it out of your attic alive. Had you passed out, it's possible you might not be reading this column. Attic temperatures in non or poorly ventilated attics can soar to 160 degree Fahrenheit. This type of heat harms your body, books, and your house.
Attic ventilation awareness is at an all time high. This awareness, I believe, is a result of the energy savings breakthroughs the home building industry has and continues to experience. Your house, when it was built, probably had state of the art ventilation. Times have changed and so must your ventilation.
Ventilating an attic needs to be done on a continual basis. The temperature and dew point of the air inside your attic needs to be as close as possible to the air on the other side of your roof. Wide differences in either of these numbers can cost you money in repairs or higher heating and cooling bills.
Poor attic ventilation in colder climates can cause frost and condensation to form on the underside of your roof. It can rain inside your attic. I have personally witnessed this phenomena. In hot climates, elevated attic air temperatures cause your air conditioner to work longer and harder. Asphalt shingles, roof boards, and insulation can be damaged by elevated temperatures.
Your photos reveal two major problems. First, you have no lower undereave or soffit ventilation. Secondly, based upon this lack of lower ventilation and the size of your attic (1,025 square feet), you need an additional 17 roof vents to satisfy most current minimum code requirements.
You need flow through ventilation for your attic spaces. Outside air enters your attic space at the bottom edge of your roof. It is exhausted near the top of your roof. These ventilating systems use wind and thermal convection to continually exchange the air in your attic with outside air. On breezy days, wind blowing across the top of your roof creates a partial vacuum which sucks air out of your attic. On days with no wind, hot air, which builds up in your attic, simply floats out of hidden vents located at the top of your roof.
Many continuous ventilation systems are available that are virtually invisible. Upper roof ventilation products can hide beneath your cap shingles. Lower roof ventilation can be achieved either behind or above your gutters. If your roof needs to be replaced soon, your roofer can remove your three metal pot vents, repair the holes, and install these newer continuous ventilation materials. When installed properly, most of these ventilating systems meet or exceed minimum building code requirements and recommendations.
