The first sign of a poorly insulated roof is often the house temperature. If your attic feels much hotter than the outside air, the ventilation system may not be working as it should. In a healthy attic, the temperature should stay within about ten to fifteen degrees of what you feel outside. When it’s hotter than that, heat builds up under the roof deck and seeps into the living space, forcing your air conditioner to work harder.

Moisture is another common indicator. Look for damp insulation, water stains on rafters, or a musty smell that lingers after humid days. You might also notice condensation on attic windows or the underside of the roof. Over time, trapped moisture can lead to mold, mildew, and wood rot.

From the outside, you might see shingles that curl, blister, or lose granules sooner than expected. When heat collects under the roof, it accelerates aging. Even in the Southeast, occasional winter freezes can cause small ice dams along the eaves when warm attic air melts snow unevenly. These issues all point to one problem: poor airflow.