The short answer
A tear-off removes everything down to the decking so the deck can be inspected and repaired. A roof-over installs new shingles on top of the old layer, saving perhaps 20 to 25 percent today while hiding deck damage, trapping heat and typically shortening the new roof's life by several years. We recommend tear-off in nearly all cases.
Side by side
| Factor | Roof-over (layover) | Full tear-off |
|---|---|---|
| Upfront cost | About 20 to 25 percent less | Baseline |
| Decking inspection | Impossible | Full inspection and repair |
| Heat retention | Traps heat, ages shingles faster | Normal |
| Added weight | Significant | None |
| Expected life of new roof | Often several years shorter | Full rated life |
| Manufacturer warranty | Often limited or void | Full |
| Future replacement cost | Higher, two layers to remove | Normal |
Choose Roof-over (layover) if
- There is exactly one existing layer and it lies flat
- The decking is known to be sound from recent work
- You are selling imminently and disclosing it
- Budget genuinely does not allow tear-off and the alternative is leaving a failing roof
Choose Full tear-off if
- You want to know what condition your decking is in, which you cannot otherwise
- There is already more than one layer, which makes a third generally non compliant
- The existing shingles are curled, cupped or uneven
- You want full manufacturer warranty coverage
- You are staying in the house
What this looks like in the Hill Country
In this climate the heat argument carries real weight. Two layers of asphalt hold substantially more heat than one, and attic temperatures of 130 to 150 degrees in a Hill Country summer already age shingles from below. A layover accelerates exactly the failure mode that is most common here.
