Pluses and Minuses of Unvented and Vented Attics

Your attic has a huge impact on the level of comfort you experience inside your home or business building.  For most of the last 100 years, most buildings had vented attics.  The theory behind having a vented attic is that air movement inside the attic would keep the attic cooler, thereby reducing heat transfer into the living spaces below.  Another benefit of a lot of air movement is reduction in mold and mildew formation in the attic which may get transferred into the conditioned space and cause health concerns for occupants.  The types of vents used in attics are typically gable vents, soffit vents and roof ridge vents.  Some attics even have mechanical vents placed strategically on the roof surface for even more ventilation.

Problems arise with vented attics if they are not sealed properly from the heated, or cooled, spaces below them.  In the winter, hot air penetrates through the ceiling and attic floor and causes a freeze thaw cycle that leads to ice dams.  Ice dams can cause substantial roof damage and interior damage.  Another issue is condensation which forms from warm air meeting the cold attic surfaces which can cause mold and mildew.  In the summer, hot air can penetrate the living spaces and lead to higher energy bills and overworking the HVAC system.

If you want to keep your attic unvented, then securely sealing the attic from the living spaces with spray foam insulation will eliminate these problems effectively and permanently.  If you never intend to turn your attic into living space, this is your best option.

The trend towards turning an attic into an unvented space has been growing steam for the past 25 years or so.  This is especially true in desert climates where thermal barriers are extremely important for energy savings and indoor comfort.  By creating an envelope of spray foam insulation in an attic, all air movement is halted and a thermal barrier is established.  Any air handling equipment located in the attic can function at insulated temperatures instead of outside temperatures creating less wear and tear on the system’s components.  Completely sealing the horizontal, vertical and inverted surfaces of an attic with spray foam is the best defense against air infiltration and heat transfer.  If you intend to convert your attic space into bedrooms or other living spaces some time in the future, give us a call so that we can discuss your options for insulating your attic and making those future spaces more comfortable.

Metal Building Insulation with Spray Foam
What is Commercial Building Spray Foam Insulation?