Home Insulation - Mold in the Attic

Welcome to the 70th episode of “On the Job”! In this episode, Larry Janesky, owner and founder of Dr. Energy Saver, takes us to the attic of a colonial home in Newtown, CT to speak about mold in the attic. Mold problems are quite prevalent in many conventionally insulated, unconditioned attics in the northeast – and in virtually any area of the country where winters are cold and houses are heated.

In this particular home in Newtown, the problem is so widespread that it is possible to see the dark mold stains all over the wooden surfaces. Such a wide infestation may eventually cause wood decay and compromise the structural integrity of the roof, but it also raises serious health concerns for the family living in that home.

What causes mold problems in the attic? As Larry will show, the problem begins with lack of proper air sealing. Heated air – the air that you pay to heat your home – rises and leaks into the unconditioned attic through all types of gaps, such as holes around pipes and wires, canned lights, unsealed attic hatches, and bathroom fans that vent into the attic instead of the outside. During the winter, an unconditioned attic is usually just as cold as the outside, and so are the roof and wooden structures. When heated, humid air infiltrates the freezing cold attic, it will cool down and  per each degree it is cooled, relative humidity rises 2.2%, often bringing the RH levels in the attic up to 100%, at which point condensation occurs all over the cold surfaces.The wood will soak the moisture and create the perfect conditions for mold to develop.

In this particular attic, the condensation problem is so significant that the nails used to secure the roof shingles began to rust and drip all over the attic.  The only effective way to stop mold from developing in the attic is to properly seal all the gaps and holes. This will help to keep heated air in the conditioned areas from escaping into the cold attic.

As it happened in this home, most builders and the typical insulation contact or will not air seal the attic before installing the insulation. That is malpractice because even if R-values are up to recommendations, common attic insulation materials such as fiberglass bats, blown fiberglass or blown cellulose, will only prevent heat from the ceiling from transferring to the attic. It will not stop air flow. Air will leak right through the insulation.

An energy efficient attic is the most important component of an energy efficient home. If your home has mold in the attic or if your heating and cooling bills are too high or even if you worry that your attic is not properly insulated visit our website or give us a call to schedule a free evaluation and estimate.