Can You Put New Shingles Over Old Ones?
Often, yes, but only once. Model building codes allow a new asphalt shingle roof over one existing layer if the old roof is flat, dry and sound. A layover saves the tear-off cost, but it adds weight, hides deck damage and can shorten the warranty. Here is how to decide.
When a layover is not allowed
The International Residential Code (Section R908.3.1.1 in recent editions) requires tearing off the existing roof when any of these is true:
- The existing roof or deck is water-soaked or deteriorated to the point that it isn't a sound base.
- The existing covering is slate, clay, cement or asbestos-cement tile.
- The roof already has two or more layers of any roof covering.
- In the 2021 IRC and later, the house is in an area of moderate or severe hail exposure and the existing covering is asphalt shingles.
Local codes can be stricter. Some cities and HOAs ban layovers outright, so check the permit office before you price the job. Wood shakes are another case. Most shingle makers won't warrant a layover directly over shakes, so plan on a tear-off or new sheathing over them.
Layover vs tear-off at a glance
| Layover (recover) | Tear-off | |
|---|---|---|
| Cost | Saves roughly $1–$5 per sq ft of tear-off and disposal | Includes removal, dump fees and deck repairs |
| Deck inspection | Not possible, so rot stays hidden | Every sheet is exposed and bad wood is replaced |
| Added weight | ≈ 250–350 lb per square for architectural shingles | None |
| Flashing and drip edge | Often reused or covered, which is a common leak source | Replaced |
| Ice barrier and underlayment | Can't be installed under the old layer | Installed to code |
| Look | Old lumps and dips telegraph through | Flat |
| Warranty | Many manufacturer upgrade warranties exclude recovers | Full eligibility |
| Next reroof | Two layers must come off, so it costs more later | Normal |
What a layover actually saves
Run your own numbers with the roof replacement cost estimator, which has a tear-off option. Material quantities for a layover are the same as for a new roof, so use the shingle calculator. Area comes from the roof area calculator.
How to tell if your roof is a layover candidate
- Count the layers. Lift a shingle at the rake edge or look at the edge behind the gutter. Two stacked shingle edges mean a layover is already there, and you can't add another.
- Walk the deck (or have a roofer do it). Soft, spongy spots mean rot, and that means a tear-off.
- Check the attic for stains, daylight, mold or sagging between rafters.
- Look at the surface. Badly curled or cupped shingles won't give a flat base. Lightly worn, flat shingles can.
- Check code and warranty: the local permit office, any HOA, and the shingle maker's recover rules.
If you do a layover, do it right
- Use longer nails that go at least 3/4 inch into the deck, or through it. A 1-1/4 inch nail that works for a tear-off is often too short. See roofing nail size.
- Cut back or "butt and run" the first courses so the new shingles lie flat over the old tabs, following the manufacturer's recover instructions.
- Replace drip edge, pipe boots and step flashing rather than covering old metal.
- Pull up and replace the ridge cap, and keep ridge ventilation open.
For roofers: quoting it
Price both options side by side. Show the tear-off line separately, and note that hidden deck damage is only found with a tear-off. A layover is easy to sell on price but tends to bring callbacks. Write down the existing layer count and deck condition in the contract, and confirm the manufacturer warranty tier that applies to a recover before you promise it.
This guide summarizes model code (IRC) rules for asphalt shingles. It is not a substitute for your local code, your permit office or the manufacturer's installation instructions.
Frequently asked questions
Can you put new shingles over old shingles?
Usually once. Model codes allow a new asphalt shingle layer over a single sound, dry existing layer, but not over two existing layers, tile or slate, a water-damaged deck, or (under the 2021 IRC) in moderate or severe hail areas.
How many layers of shingles are allowed on a roof?
Two at most under the IRC: the original layer plus one recover. A roof that already has two layers must be torn off before reroofing.
How much does a layover save compared to a tear-off?
Typically the tear-off and disposal cost, about $1 to $5 per sq ft of roof, or roughly $2,000 to $10,000 on a 2,000 sq ft roof. Some of that is lost to new flashing and any hidden deck repairs.
Does a second layer of shingles void the warranty?
Not always, but many manufacturers limit or exclude their enhanced warranties on recovers. Check the specific product warranty before choosing a layover.
What size nails for a roof layover?
Long enough to penetrate at least 3/4 inch into the deck or go through it, usually 1-1/2 to 1-3/4 inch for a recover instead of 1-1/4 inch.
Last reviewed 2026-10-10. Results are estimates for planning; confirm quantities with your supplier and requirements with your local building code and the manufacturer's instructions.