attic ventilation

At Pro Roofing & Siding, we love working in the Marietta region. Of course, we have also experienced the oven-like levels of southern heat during summer months. With average July high temperatures of 89 degrees and 217 days of sunshine a year (according to Sperling’s Best Places), Marietta homeowners are all too familiar with the effects of high temperatures and humidity. What you may not know, but we at Pro Roofing & Siding see every day, are the effects of our climate combined with poor attic ventilation.


Every summer brings news alerts against leaving family pets in closed cars, and rightfully so. Consider, though, that temperatures in a Marietta attic with poor ventilation can reach 150 degrees. That is not just sweltering, that is dangerously hot. If you store anything—keepsakes, clothes, holiday decorations—in your attic, those stifling temperatures can bake and destroy your possessions.

Other damage caused by no or little attic ventilation:

  • Damage to sheathing—The wood sheets under your shingles can de-laminate, or split apart into layers, from glue failure in the high heat
  • Damage to underlayment or water shield—Between sheathing and shingles is rolled roofing material that protects your whole roof system; baked in hot temperatures, it can degrade and lose its waterproofing
  • Damage to shingles—Between the sun’s infrared heat beating down on them and the conductive heat rising inside your hot attic, the asphalt in your shingles can break down, leading to early roof replacement


Worse, perhaps, than heat buildup in your attic from improper attic ventilation is the condensation that can form from high heat and high humidity. In summer, trapped moisture can lead not only to mold and mildew, but can ruin insulation, sheathing, and wood framing members such as joists and rafters. As the wood gets wetter, it becomes an attractive snack for carpenter ants and termites.


The ideal temperature for your attic should be the air temperature outside. This keeps the attic properly cool in winter and warm (not hot) in summer, so your home’s living space is completely isolated from it. Through proper insulation, the attic does not draw heat from your home in winter, and does not burden your central air conditioner in summer.

Reaching that ideal means properly installed ridge and soffit vents. Contact the professionals at Pro Roofing & Siding today so we can help provide adequate attic ventilation for your Marietta home.

Keep Your Roof Cool this Summer