Two identical roofs, same shingle, same crew, same street. One lasts twenty four years and the other is done in fourteen. Nine times out of ten the difference is what is happening underneath.
Your attic is cooking the roof from the inside
A Georgia attic in July can run well past 130 degrees. Asphalt shingles are designed to take heat from above, from the sun, which is what they were tested for. What they handle poorly is being baked from both sides at once. The asphalt dries out faster, the mat gets brittle, granules let go, and the roof ages years ahead of schedule.
Most manufacturers know this well enough to tie their warranty to it. Install their shingle over an attic that is not properly ventilated and the warranty coverage gets a lot narrower.
Ventilation is two halves, and people only remember one
Everyone knows about the ridge vent. That is exhaust, the hot air leaving at the top. What gets forgotten is intake, the cool air coming in low at the soffit. You need both, and roughly in balance.
A ridge vent with blocked soffits does not move much air. It just sits there. We see it constantly: someone insulated the attic, packed the batts right out over the top plate, and sealed off every soffit vent in the house without realizing it. The roof gets a ridge vent, the homeowner is told they are ventilated, and the attic keeps cooking.
What good ventilation looks like
- Continuous ridge vent along the peak, cut to the right width
- Clear soffit intake all along the eaves, with baffles keeping insulation off the vents
- Intake area at least matching exhaust area, so the system actually pulls
- Bathroom and kitchen fans ducted outside, not dumped into the attic
- No mixing of ridge vent with powered fans or box vents on the same plane, which lets the system short circuit and pull air from the wrong direction
How to tell yours is wrong
Go into the attic on a hot afternoon. If it feels significantly hotter than outside and the air is dead still, you have a problem. In winter, look for frost or damp sheathing on the underside of the roof deck, which is moisture that had nowhere to go. Ice on a Georgia roof edge after a cold snap is another sign heat is escaping into the attic instead of out the ridge.
Fix it while the roof is off
The one time it is cheap to correct ventilation is during a replacement, when the deck is exposed and the eaves are accessible. We size the intake and exhaust to the actual attic on every roof we install. It is not an upsell, it is the difference between the roof you paid for lasting its full life or two thirds of it.
Written by the crew at GSP Exterior Works, a roofing, gutter and exterior contractor working across Forsyth, Cherokee, North Fulton, Gwinnett, Hall, Dawson and Paulding counties. Every roof we quote gets a free drone inspection first.