Builderz Blog – Insulation & Ventilation


We are doing an insulation and ventilation upgrade in Mansfield. When I went into the attic to block the existing gable vents (more on that later) I was amazed at the amount of moisure on the rafters and the plywood. This happens when the amount of air escaping into  the attic from the living area is more than the ventilation system can handle and when your home is under insulated.

I’m sure we have all heard the term relative humidity in our local weather reports. The exact same conditions apply to our attics. The warmer the air, the more moisture it can carry, conversely the colder the air the less moisture the air can handle. When we are heating our home and 70 degree air is escaping into our 30 degree attic the amount of moisture transferred can result in condensation and in some extreme cases it is raining in the attic!

There is a cure, first insulate your ceiling properly, the Massachusetts Energy code calls for a minimum of R-38. The home we were working on had R-11 at the most.

The second part of the equation is ventilation to keep what warm air that does infiltrate the attic moving. In the old days we would put vents on each end of the house and say good enough. Not so anymore, one factor that few people realize is tree count and location. Trees will stop the air flow into and out of gable vents, also with the newer homes, 20 years or less are so much tighter that they require more venting; that is why the Massachusetts Building code requires venting from the soffit and ridge. This system moves air from the bottom of your attic up and out the top of your roof.

I mentioned earlier about blocking the gable vents, we were installing the modern venting system I just described. Have you ever ridden in an S U V or a pick up truck with the rear window open and watched all the leaves and dust blow in? The same aero-dynamic occurs when you have both gable vents and the soffit/ridge vent system thus causing more cold air to rush in trapping the moisture in your attic.

So remember insulate and ventilate!

Anthony P. LaPuma

P.S. Would you like to know how you can have your project completed at virtually no cost to you? Get the details of our “CUSTOMER LOYALTY REFERRAL REBATE PROGRAM” by calling today!

, , ,

Comments are closed.

Powered by WordPress. Designed by Woo Themes