Tear-Off vs Overlay (Re-Roof)

When it's time for a new roof, you have two options: tear off the existing roof down to the deck and start fresh, or install new shingles over the old ones (overlay). Most homeowners ask about the price difference; what they should ask about is the long-term cost difference. **Tear-off.** Strip existing shingles, underlayment, sometimes flashing down to bare deck. Inspect deck for rot/damage. Install new ice-and-water shield, drip edge, underlayment, and shingles. Adds $1.00-$1.75 per sq ft per layer of existing material. **Overlay.** Install new shingles directly over the existing first layer. Faster, cheaper upfront ($2-$4 per sq ft less than tear-off). Allowed by most codes for one additional layer (never more than two total). Why overlay is usually a mistake: - New shingles can't bond properly to the irregular old surface - Combined weight stresses the deck and rafters - Voids most manufacturer warranties (you can't warranty a roof you didn't inspect the deck on) - Hides deck rot, ventilation problems, and flashing issues until they become emergencies - Reduces new roof life by 2-5 years on average The exceptions where overlay is reasonable: short-term ownership (you're selling within 3 years), perfectly flat existing layer in good condition, or budget that genuinely can't stretch to tear-off. Even then, walk the homeowner through the trade-off clearly. For estimating: SatelliteQuotes (and any quality estimating tool) lets you make tear-off a configurable per-square add-on with clear pricing. Always show both options on quotes when relevant — the price gap usually makes the right answer obvious once it's spelled out.