Doesn't my attic need ventilation? Attics were traditionally vented to remove excess moisture and reduce heat build-up. Modern research suggests that venting attics may actually make the situation worse and greatly add to our energy costs. Because hot air rises, vented attics create a “chimney” effect that continuously pulls moist air from crawl spaces and basements into the attic, contributing to a greater moisture load. Further, during the night the colder air cools the roof which causes condensation to form. And to make matters worse, radiant heat during the day heats up the roof and easily passes into the attic generating excessive temperatures which then pass into the living space below.
We can solve all of these moisture and heat build-up problems by applying spray foam directly to the underside of the roof deck and sealing off the attic from the outside environment. By sealing off the top of the house we eliminate the “chimney” effect that would otherwise occur. We further prevent the hot moist air by day and the cold air at night from continuously venting in and out of the attic; stopping moist air from entering the attic all together is the best way to control moisture related problems. Moreover, spray foam also seals off the roof sheathing, rafters and other exposed wood sources, thereby preventing condensation and rot from ever occurring.
A “conditioned” attic also greatly reduces our cooling loads during the summer and heating loads during the winter. By foaming the underside of the roof deck, thermal radiation, the primary source of heat transfer to an attic, is prevented. Attic temperatures stay cooler and more consistent during the summer, and during the winter heat loss through the attic is mitigated. Additionally, since spray foam is an excellent thermal barrier, ice damming during the winter is prevented since heat is not easily transferred to the roof causing snow to melt.
A “conditioned” or unvented attic also reduces the stress load on an HVAC system and any ductwork which may be located inside an attic. A vented attic exposes heated or air-conditioned air in ductwork to extreme opposite temperatures, reducing the efficiency by as much as 10%.
* In a test conducted at Oak Ridge National Laboratory, funded by the US Department of Energy, a vented attic with fiberglass on the floor was found to have an attic temperature of 108° when the exterior temperature was 110° and the interior temperature 70°; the unvented attic with spray foam applied to the underside of the roof had an attic temperature of less than 78°.
For more information you can email Juan directly at Juan@AllFoamTech.com or call 239-599-3277