Leakage in Attic After
Wind-Driven Rain

Possible cause: Leaky or inadequate shingle underlayment or deteriorated
flashing

Leakage in Attic After
Ice Build-Up

Possible cause: Inadequate shingle underlayment allows water from ice dams
to leak into attic

Blistering and/or Peeling of
Interior and/or Exterior paint

Possible cause: Excessive temperature or high humidity due to poor attic
ventilation

Stains on Interior Ceilings and Walls
or Mold and Mildew Growth

Possible cause: Inadequate or faulty shingle underlayment allowing leakage
or inadequate

Exterior Decay,
Sheathing, and/or Siding

Possible cause: Poor attic ventilation

Missing, Cracked,
or Curled Shingles

Possible cause: Shingles have reached the end of their useful life

Dark, “Dirty-Looking” Areas 
On Your Roof

Possible cause: Loss of granules due to age of shingles

Excessive
Energy Costs

Possible cause: Insufficient attic ventilation causes heating/cooling
system to run excessively

In warm weather, inadequate ventilation will trap hot air in the attic,
causing air conditioning systems to work harder, or leaving your home’s
interior hotter and less comfortable. Attic Ventilation: In both hot and
cold weather, insufficient attic ventilation may cause moisture in the
attic to become trapped and condense on the rafters. This condensed
moisture can drip down onto the insulation and reduce its effectiveness.
Excessive energy costs can result.