Roofing · Compare
Tear-off vs recover (overlay): which commercial reroof to spec
Recover is cheaper and keeps the building closed, but code and a moisture survey decide whether it is even legal.
Short answer
Run the disqualifiers first, then price it: if the roof already carries two coverings, or a moisture survey finds widespread wet insulation, or the deck is failing, the code and the condition force a tear-off. Only when the roof is a single sound, dry layer over a sound deck is recover genuinely on the table, and then it usually wins on price by roughly a quarter. The single biggest deciding factor is the condition of the existing roof, which you confirm with a moisture survey and core cuts, not by looking at the surface.
Tear-off vs Recover (overlay): side by side
| Factor | Tear-off | Recover (overlay) |
|---|---|---|
| What stays / what goes | Strips everything above the deck; only the deck stays and gets inspected | Old membrane, insulation, and deck all stay; new membrane goes over the top |
| Upfront cost | Higher; tear-off and disposal add roughly 1-3 dollars/sq ft on top of the new system | Lower, usually about a quarter less; skips demolition, dumpsters, and tipping fees |
| Service life | Full reset, commonly 20-30 years for a maintained membrane on an inspected deck | A defined stretch of added life on an already-sound roof, not a full reset |
| Code / standard (IBC) | Called replacement; the path required once two coverings already exist | Barred over water-soaked or deteriorated roof, and no more than two coverings total |
| Deck / hidden condition | Only chance in ~30 years to inspect and photograph the bare deck | Leaves deck and insulation buried; wet substrate keeps rotting the deck |
| Wind attachment | New fasteners land in a freshly inspected deck; pullout is known | Fasteners must reach through old roof to the deck; pullout must be tested, not assumed |
| Building operations | Opens deck in sections over occupied space; needs strict daily dry-in | Building stays closed through the job; old roof is the temporary roof |
| Warranty | Manufacturer warrants the whole assembly, deck up | Needs written manufacturer approval up front; often tighter or shorter terms |
| Disposal | Real tonnage; plan dumpsters, chutes, and any recycling route | Little to none beyond cut-out wet board |
Which should you pick?
Choose Tear-off when
- The roof already carries two coverings; the IBC bars a third, so tear-off is required
- A moisture survey finds widespread wet insulation or the deck is rusted, rotted, or failing
- You want the full service-life reset, a fully warrantable assembly, and the one look at the bare deck
- Life-cycle math per year of service favors the reset even though it loses the bid-day number
Choose Recover (overlay) when
- The roof is a single sound, dry layer over a sound deck, confirmed by survey and cores
- Lowest upfront cost matters and you can spend it on a roof with real remaining base life
- A critical or low-leak-tolerance building needs to stay closed through the work
- Any limited wet areas can be cut out and replaced with dry insulation before overlay, and the manufacturer approves the recover in writing
Bottom line
It depends on the existing roof's condition and layer count, in that order. The disqualifiers are absolute: two existing coverings, widespread wet insulation, or a failing deck each force a tear-off no matter how attractive the recover price looks. Only when the roof clears all of them is recover legitimately on the table, and then you weigh its lower cost against the tear-off's full reset of life and warranty using cost per year of service bought, letting the building's importance and leak tolerance break a close call. The cheap recover over a roof that needed the strip is the expensive mistake: you pay for the recover, then pay for the tear-off a few years early once the trapped water finishes the deck.
FAQ
Is a roof recover cheaper than a tear-off?
Yes, usually by roughly a quarter, because a recover skips the demolition, dumpsters, and disposal fees that add about 1 to 3 dollars per square foot to a tear-off. But a tear-off resets the full service life and warranty on an inspected deck, so it often wins the cost-per-year math. Price the years the recover actually buys, not just the invoice.
When is a roof recover not allowed?
A recover is barred when the existing roof will not serve as a sound base. The IBC prohibits it over water-soaked or deteriorated roofing, and it allows no more than two coverings total, so a roof already carrying two forces a tear-off. Wet insulation and a rusted or rotted deck also take it off the table. Limited wet areas can be cut out and replaced first; widespread saturation means strip it.
Do you need a moisture survey before choosing?
Yes. A moisture survey by infrared or nuclear scan, confirmed with core cuts, is what tells you whether a recover is even legal, because the code bars recovering over wet insulation. It maps trapped water you cannot see from the surface, and the cores set the wet-versus-dry threshold. Skip it and you recover over damage that turns into an early tear-off with a rotted deck on top.