Can you shingle over architectural shingles?
What code says
The International Residential Code allows a recover only over a single existing layer that is not water-soaked or deteriorated. A roof that already has two layers must be torn off. Georgia adopts the IRC with state amendments, and local rules can be stricter.
Why architectural shingles make a poor base
- Uneven surface: the laminated tabs vary in thickness, so new shingles lie over ridges and hollows instead of a flat plane.
- Weak sealing: sealant strips cannot bond fully across those humps, which invites wind damage.
- Nailing problems: nails can land over hollow spots and sit crooked or loose.
- Looks: the old pattern shows through as a wavy, lumpy roof.
- Heat: two layers can hold more heat, which does the new shingles no favors in a Georgia summer.
What you would give up
Overlaying skips the deck inspection and the chance to replace rotten sheathing, new drip edge, fresh underlayment, leak barrier in the valleys, and new flashing. It also doubles the shingle weight on the framing and doubles the tear-off cost when the roof is finally replaced. Manufacturer warranty terms may be reduced on recovers.
Insurance and resale
Some insurers and buyers' inspectors flag second layers, and a future storm claim may involve tearing off both.
The bottom line
The savings from skipping tear-off are real but short term. For most Georgia homes, removing the old roof to the deck is the better investment. See roofing over existing shingles and OSB vs plywood roof decking.