Attic Insulation Gaps and Goofs

Smart Inspector Science

By Tom Feiza, Mr. Fix-It, Inc. |

We have all inspected attics and noticed large gaps in the insulation covering the ceiling of the living space. Or maybe they were just small areas of uneven insulation. We make a note in our inspection report about gaps in insulation, but how did they get there?

Many homes are constructed with dropped soffits over the kitchen and bath. These dropped soffits filled in gaps above cabinets.

At some point, an insulation contractor or carpenter spread a plastic Visqueen vapor barrier over the rough framing of the ceiling and exterior walls to stop airflow from the heated space. As they covered the ceiling, that dropped soffit framing was in the way. So what did they do? Who knows? (Illustration I011)

I011 - Heat and Air Bypass at Inside Soffit

An all-too-common fault

It’s very common to see this faulty installation: the dropped soffit is not blocked at the attic floor and not covered by the vapor barrier. These gaps in attic insulation create a huge potential problem, since heated air contains lots of moisture. (See Picture – Insulation Gap at Dropped Soffit)

Insulation at Dropped Soffit

When you notice gaps or disturbances in the insulation, lack of blocking to support the insulation, or lack of a continuous vapor barrier, check the roof sheathing for signs of condensation and moisture. Look at the insulation for black stains that result from filtering dirt out of the air flow.

Gaps at chimneys

Insulation Gap at Chimney

Air gaps are required at chimneys for fire safety but as we tighten homes the large gap and air leaks can cause ice dams and attic moisture issues. Today when insulation is added to any attic, proper fire- resistant air sealing must be completed around all penetrations from the heated space, including the chimney. In the picture, note the insulation and the black stains. The fiberglass insulation is a great dirt filter for the air flow from the basement to the attic. Talk about stack pressure!

Watch your step

When peering into an attic, keep in mind that gaps in the insulation could indicate the existence of a dropped soffit or a stairway. Watch for moisture issues. Making a report notation for gaps in the insulation, and the vapor barrier and proper air sealing. And if you ever crawl around an attic, remember: these gaps can be quite large, and there may be no framing to support you.

Weather Tight Corporation

Tom Feiza has been a professional home inspector since 1992 and has a degree in engineering. Through, he provides high-quality marketing materials that help professional home inspectors boost their business. Copyright © by Tom Feiza, Mr. Fix-It, Inc. Reproduced with permission.

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