Roof overlay vs tear-off: which one can your roof take?
"And no down sides to an overlay if done right?"
One commenter in a roofing thread asked that. An overlay has trade-offs, and your roof has to qualify for one. One roofer quotes new shingles over the old ones, and another says it's a full tear off and new roof. An overlay can be cheaper but is not always the best choice1, and tearing off typically gives a longer roof life1. Below: the checks that decide whether an overlay is allowed, what it can hide, and what to get in writing.
Quick answer:
- Ask both roofers whether your roof qualifies for an overlay, and have them say why or why not.
- Find out how many layers of shingles are on the roof now: two or more layers means all of them come off2.
- Request both options in writing, with the work, materials, timeline, cost breakdown and warranty details3 listed.
- Read the shingle maker's overlay instructions before you agree to an overlay, because an asphalt-shingle overlay must follow them1.
On this page
Today you control one thing: ask each roofer to put in writing what they found on your roof and what they would do about the wood underneath.
What the two quotes mean
An overlay puts new shingles over the existing layer. A tear-off removes the old covering first, so the roof deck (the wood under the shingles, also called sheathing) is bare and can be seen. With a tear-off, defects in the deck are revealed and can be repaired before the new roof goes on1.
It's natural to wonder whether ripping it all off is really needed. Another reply in a roofing thread put it bluntly: "I've never met a roofer who didn't think you needed a tear off." You don't have to settle that on trust. Settle it with local rules and written details.
Can your roof take an overlay?
Only if it passes your local building department's checks, so ask them what applies at your address. These examples come from one Michigan city:
- Condition: a pre-inspection checks that the current layer of shingles is in good condition2.
- Layers: only two layers of shingles in total are allowed2, and when a roof already has two or more layers, all of them must be removed to keep the roof weather-resistant and its structure supported2.
- Dryness: the existing surface must be completely dry2 so moisture isn't trapped under the new layer.
If your roof fails one of these, the overlay quote may not be an option. Ask the roofer who offers it to show how they checked.
Wondering whether the job also needs a permit where you live? Do you need a permit to replace a roof.
What an overlay can hide
The wood underneath. An overlay leaves the deck covered, so a damaged spot stays out of sight, while deck defects are revealed when the roof is torn off1. Wetness is part of the reason the surface must be dry: trapped moisture can quickly deteriorate both the new covering and the existing sheathing2.
Two practical asks follow. Ask the overlay roofer how they checked the deck. Ask the tear-off roofer for photos of any damaged wood, since nobody knows the amount until the old roof is off. You can send this:
Please write into the quote a price per sheet for replacing any damaged decking. Please send photos of each damaged spot and get my OK in writing before replacing it.
If the wood underneath is already rotted, what does that mean? What roof rot means and what to get in writing.
Does an overlay hurt the warranty?
That depends on the shingle maker's overlay terms, so read them in writing before you choose. An asphalt-shingle overlay must follow the manufacturer's installation instructions for overlays1. Ask each roofer which shingle they would use and for the warranty details of that exact option.
You may also run into the "25% rule." It comes from Florida: a building-code provision limits how much of a roof section can be repaired, replaced or recovered in 12 months unless the entire roofing system or section is replaced4.
Checklist to compare both quotes
Put these in front of both roofers before you compare prices, and keep the photos and dates together:
- Whether the job is a full tear-off or an overlay, and why that fits your roof.
- A written explanation of the work, a materials list, a timeline, a cost breakdown and the warranty details3.
- How many layers are on now, and whether the covering was found dry and in good condition.
- How damaged decking is handled and priced.
- A photo of every problem the roofer says needs fixing.
Want to see what a full replacement quote should list, line by line? What is included in a roof replacement.
Quick questions
Does an overlay need a permit?
Ask. In one Michigan city, this type of work requires a permit2. Ask each roofer whether the permit is in the quote and who pulls it. One reply in a roofing thread asked the question to put to them at the end: "Was a permit pulled and was it signed off? Did you pay?"
Does a second layer add weight?
Roofing materials are heavy, so multiple layers can affect how much winter snow a roof can hold1. If snow piles up where you live, raise it with the roofer and your building department.
What does a full tear-off job include?
It varies by roofer, so read the quote. As one example, the FORTIFIED high-wind re-roofing checklist calls for removing all existing roofing material and replacing any damaged wood5. It's a good reason to ask how damaged wood is handled in yours.
What if the two roofers disagree about the deck?
Ask each one to point to the problem in photos. If the answers still differ, a written quote from a different company on the same terms can help you decide.
Sources
2. City of Oak Park, MI: Roofing Guidelines for Residential Properties
3. North Carolina Department of Insurance: Avoiding predatory roofing scams
5. IBHS FORTIFIED: FORTIFIED Home Re-Roofing Checklist
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