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Can You Put New Shingles Over Old Shingles?

When the International Residential Code allows a roof recover, when it doesn't, and what to ask your contractor before skipping a tear-off.

Updated
Reading time2 min
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Key takeaways

  • The 2021 IRC can allow a new covering over an existing roof, called a recover.
  • It's not allowed over two or more existing layers, or a water-soaked or deteriorated roof.
  • Local rules and shingle instructions can be stricter, so check them first.

Sometimes. The 2021 International Residential Code (IRC) calls this a roof recover. A roof replacement removes the existing layers down to the deck.

When a recover isn't allowed

IRC Section R908.3.1.1 says a recover isn't permitted where:

  1. The existing roof or covering is water-soaked, or has deteriorated so that it's no longer an adequate base.
  2. The existing covering is slate, clay, cement or asbestos-cement tile.
  3. The existing roof has two or more applications of any type of roof covering.

So if your roof already has two layers, the code requires a tear-off before new roofing goes on.

Check what applies to you

The IRC is a model code, and your local version may differ. Ask your building department about its rules and permits, and read the new shingle's instructions and warranty terms.

What to ask before skipping a tear-off

A recover leaves the deck hidden, so ask your contractor:

  • How many layers are on the roof now, and how did you check?
  • How did you check the deck and any soft spots?
  • What happens to the flashing, drip edge and vents?
  • Does the shingle's warranty cover installation over an old roof?
  • Is a permit needed, and who gets it?
  • What would a full tear-off add to the price?

Get the answers in writing, along with the number of squares in the quote.

Decide: recover or tear off?

What you find Under the 2021 IRC
Two or more existing layers No recover
Water-soaked or deteriorated roof No recover
Slate, clay, cement or asbestos-cement tile No recover
One sound layer A recover may be allowed, so check local rules

Asbestos-cement materials need extra care. Don't cut, break or remove them yourself, and ask a qualified professional.

Frequently asked questions

Can I have three layers of shingles?

Not under the 2021 IRC's recover rule. A recover isn't allowed where the roof already has two or more applications of roof covering.

What is a roof recover?

It's a new roof covering installed over an existing one, without removing the old layer first.

Is a tear-off always required?

No. The model code allows a recover if none of the exceptions apply and local rules permit it. Your local rules or product instructions may be stricter.

Sources

We use primary sources where we can: building codes, federal rules and manufacturer documents. Read our editorial standards.