A roof overlay puts a new layer of shingles over the existing layer, while a tear off strips the old roofing down to the deck before the new roof goes on. For most roofs our crews recommend the tear off, because it lets the roofer see and fix the wood underneath, and an overlay is only a reasonable option in a narrow set of cases that the shingle manufacturer and your local building rules both have to allow.
That is our crews' view, and it is not a universal rule. Some roofs do get overlaid, some manufacturers and cities allow it under conditions, and the right answer depends on what is under your shingles today. This page walks through the trade-offs in plain terms so you can ask better questions. We do not list prices here, and anything about code or warranty should be confirmed with the source named at the end.
Key takeaways
- An overlay is a second layer of roofing over the first. A tear off removes the old layer (and usually the old underlayment) so the new roof starts on a clean deck.
- The biggest difference is visibility. You cannot inspect, repair or replace deck boards you cannot see.
- An overlay adds weight and can carry forward the problems of the first layer: curled edges, bumps, old fastener holes, trapped moisture.
- Requirements about how many layers are allowed, and whether an overlay is permitted at all, vary by city and county and by shingle manufacturer. Ask your building department or roofer, and ask to see the manufacturer's wording.
- Our crews' practice is to tear off. We say so plainly, and we also tell you what an overlay would and would not give you.
What is the difference between a roof overlay and a tear off?
Overlay (also called a reroof over existing shingles, or a second layer) means new shingles are installed on top of the old shingles. The old roof stays in place and becomes part of the new roof system. Prep work usually involves nailing down or trimming anything that is loose, setting new edge metal and flashing where needed, and then installing the new layer.
Tear off (also called a full removal or strip) means the old shingles, old underlayment, and often old nails and edge metal are removed down to the bare deck. The deck is checked, damaged boards are replaced, and a new roof system is built from the deck up: underlayment, accessories, flashing and shingles.
Both are legitimate roofing terms and both appear on estimates. The trouble is that a one-line estimate can hide which one you are getting. Ask your roofer to write "tear off to deck" or "overlay" explicitly, and to say what happens to the old underlayment.
One more bit of vocabulary: in Oklahoma you may also hear "overlay" used for the deck. On some older homes the roof deck is made of spaced boards, and a crew may lay sheet material such as OSB over the old boards before the roof goes on. That is a deck overlay, which is a different thing from a shingle overlay. Our owner's field notes mention a small house addition where the plan was to add OSB over the current wood decking system. It is a normal part of a redeck, and you can read how it works in our explanation of what a redeck roof is.
How do an overlay and a tear off compare?
The table describes general tendencies. Individual roofs, products and local rules differ, so treat it as a starting point for questions.
| Topic | Overlay | Tear off |
|---|---|---|
| What happens to the old roof | Stays in place under the new layer | Removed down to the deck |
| Deck inspection | Deck stays covered; problems are hard to see | Deck is exposed and can be inspected and repaired |
| Hidden damage | Can be sealed in and found later | Found and addressed before the new roof goes on |
| Added weight | Adds the weight of a second layer to the structure | No added layer; weight is roughly like for like |
| Surface smoothness | Old bumps, curls and ridges can telegraph through | New roof sits on a flat, prepared base |
| Effort and mess on the day | Usually less labor and less debris hauling | More labor, more debris, more day-of disruption |
| Cost relationship | Usually lower up front; no dollar figures here | Usually higher up front; ask for an itemized estimate |
| Manufacturer warranty | May be limited or not offered on an overlay; check each manufacturer | Standard path for the manufacturer's warranty programs |
| Code and permit rules | Layer limits and overlay rules vary by city and county | Layer limits are rarely an issue because the old layer is gone |
| Repair or sale later | Next owner or next roofer faces two layers to remove | One layer to remove at the next replacement |
| Best suited to | A sound, flat, single-layer roof in good shape, where rules allow it | Most roofs, and any roof with doubts about the deck |
"Usually lower" and "usually higher" describe how the two options tend to relate, not what they cost.
What hidden damage can an overlay cover up?
This is the heart of the question. Shingles are the visible part of a roof, but the deck underneath is what holds everything up. Over many years of Oklahoma heat cycles, wind and storm weather, several things can happen out of sight:
- Soft or deteriorated deck boards. Moisture from a slow leak or from poor attic ventilation can weaken wood. You often cannot tell from above.
- Gaps and spacing. Older homes may have spaced board decking, where the shingle nails have little to bite into between boards. Nailing a new layer over that is a poor foundation.
- Old fastener holes. Every previous roof leaves nail holes in the deck. Our owner has posted a photo and a comment about the old and new decking in one frame, noting that there are hundreds of holes when the roof comes off. It is a good reminder that a deck has a history, and you only see the whole story when the old roof is removed.
With an overlay, all of this stays covered. If the problem is minor, nothing happens. If it is not, the new roof can end up hiding a developing issue until it becomes a leak, and then a repair means removing two layers to reach it.
How does the extra weight and a second layer affect the roof?
A second layer of shingles adds weight to the roof structure. Most roofs are built to carry some amount of roofing load, and building rules limit how many layers may be on a house, but the numbers and the rules vary, and we do not state them here. Ask your building department or roofer what applies where you live.
Weight is not the only concern. A second layer can also:
- Telegraph the old surface. Curled, cupped or bumpy shingles underneath can show through the new layer, which affects how the roof looks and may affect how it lays.
- Complicate flashing. Step flashing, chimney flashing and pipe boots work best at specific heights. Adding a layer changes the build-up around every penetration, and it can be hard to get a clean result.
Why does decking inspection matter so much?
Because the deck is what the whole roof stands on. In a tear off, once the old shingles and underlayment come off, the deck is visible and the crew can mark damaged boards, replace them, and fix any places where fasteners will not hold. In an overlay, that whole step is skipped.
The decking story in Oklahoma has a couple of local twists. Our crews see spaced decking on older homes, and the owner has noted that plywood has been so expensive at times that OSB is the usual replacement. When a roof estimate changes mid-project, the deck is frequently the reason. If you want to know why, read our guide on why a roof estimate changes. For a deeper look at the old paper layer itself, see our comparison of synthetic underlayment and felt.
If a roofer proposes an overlay, ask how they will evaluate the deck without removing the old roof. Sometimes the answer is an attic inspection from below and a look at the roof from the ground and the edges. That tells you something, but it is not the same as seeing every board.
What do manufacturers and building codes say about overlays?
Two sets of rules apply, and they are separate.
The shingle manufacturer. Manufacturers publish installation instructions and warranty terms. Some say little about overlays, some allow them under conditions, and some limit or exclude warranty coverage if the product is installed over an existing layer. The only reliable answer is the written instruction for the specific shingle on your estimate. Ask your roofer to show you the page.
Your city or county. Local building rules typically address how many layers of roofing a home may have and may set conditions about overlays. Requirements vary by city and county; ask your building department or roofer what applies at your address. We do not quote section numbers or layer limits on this page, because they differ and change. See our short answers on how many layers of shingles are allowed and whether you can put new shingles over old.
Which should you choose: overlay or tear off?
Here is a practical way to decide. This is the decision section most people need, so take it slowly.
- Count the layers you already have. If there are already two layers, an overlay is generally not on the table. Ask your roofer or building department to confirm for your address.
- Check the manufacturer first. Find out whether the shingle you want is allowed over an existing layer and whether the warranty applies. If the answer is unclear, treat that as a reason to lean toward a tear off.
- Look at the condition of the existing roof. If the shingles are curling, cupping, heavily granule-worn, or showing bumps and waves, an overlay is likely to inherit those problems.
- Think about the deck. Any sign of soft spots, sagging, past leaks, or attic moisture is a strong argument for tear off, because you want to see and repair the wood.
- Be honest about the budget. If an overlay costs less, ask for both options as separate itemized lines so you can see the difference and decide with facts.
Our crews' view: we recommend a tear off for nearly every roof we look at. The hundreds of holes under an old roof are a good reminder of what an overlay would leave sealed in. If you are looking at an overlay anyway, ask for the manufacturer's written allowance and a written statement of what the roofer will and will not warrant.
What are the common pitfalls with overlay vs tear off?
- Choosing on the lowest number without asking what it includes. An overlay quote and a tear off quote are not the same product. Compare scope, not totals.
- Assuming the manufacturer warranty carries over. Check whether an overlay changes the warranty. Do not assume.
- Assuming code is the same everywhere. Requirements vary by city and county. A neighbor's experience in a different town may not apply.
Frequently asked questions
Is a roof overlay cheaper than a tear off? Usually the up-front work is smaller, so the quote often is, too. But the comparison is incomplete without the longer view: hidden deck issues, possible warranty limits, and a more complicated removal later. Ask for both options itemized.
Can I put new shingles over old shingles? Sometimes, where the shingle manufacturer and your local building rules both allow it, and where the existing roof is flat, sound and a single layer. Many roofers, including our crews, prefer a tear off. See our short answer on putting new shingles over old.
How many layers of shingles can a roof have? Requirements vary by city and county. Ask your building department or roofer what applies at your address. We do not state a number here.
Does an overlay void my shingle warranty? It can limit or change it, depending on the manufacturer and the product. Read the warranty for the shingle you are buying, and ask your roofer to point to the relevant wording.
Why would a roofer recommend a tear off after hail damage? Because the deck, flashing and underlayment may also need attention, and a tear off shows the full picture. Whether storm damage is covered, and how, is a matter for your policy and your insurance agent. We do not predict coverage outcomes.
How can I tell what is under my shingles without going on the roof? You cannot see the deck from the ground, but you can look at the attic side for stains, daylight, damp insulation or dark wood, and you can note shingle condition from the ground. Please do not climb onto the roof. A roofer can inspect safely and explain what they see.
Can a roofer compare overlay and tear-off options in writing?
If you are weighing an overlay against a tear off, we can walk through the roof with you, explain what we see from the ground and the attic, and put both options on a written, itemized estimate so you can compare them. An inspection tells you about the roof; it does not predict your insurer's decision, and we will not tell you otherwise. Call Total Roof Protection OKC at 405-415-5841, and see our roofing services.