# Tear-Off vs Overlay

> Tear-off removes the existing roof covering down to the deck; an overlay (recover) installs a new covering over the old one where codes permit.

- URL: https://roof.wiki/tear-off-vs-overlay/
- Topic: Installation & Methods
- Also known as: recover; re-cover; layover; roof overlay; shingle-over
- Regions: North America, Global
- First published: 2026-11-02 · Last reviewed: 2026-11-02
- Cite as: "Tear-Off vs Overlay." roof.wiki. https://roof.wiki/tear-off-vs-overlay/

## Key facts

- **US code section:** IRC R908 (Reroofing)
- **Common US limit:** Tear-off required if two or more coverings exist
- **Coverings that cannot be overlaid (2018 IRC):** Slate, clay, cement, asbestos-cement tile

When a roof is replaced, the old covering can either be removed completely (a **tear-off**) or left in place with the new roof installed over it (an **overlay**, also called a **recover** or "layover"). Codes in many places limit when an overlay is allowed, because extra layers add weight, hide deck damage and can make the new roof less flat and less durable.

## Code limits in the United States

The International Residential Code (IRC), adopted with local amendments across much of the US, treats overlays in section R908 (Reroofing). In the 2018 edition, section R908.3.1.1 does not permit a recover, so tear-off is required, when:

- the existing roof or roof covering is water-soaked or has deteriorated so that it is not an adequate base;
- the existing covering is slate, clay, cement or asbestos-cement tile; or
- the roof already has two or more applications of any type of roof covering.

In practice this usually means one existing layer of asphalt shingles may be covered once, giving two layers in total. Local rules can be stricter. The City of Norman, Oklahoma, for example, does not allow a recover over any existing asphalt shingle layer, while Bloomington, Minnesota, applying a code based on the 2018 IRC, allows a total of two layers before tear-off is needed.

## Overlay technique

Where an overlay is permitted, Canadian guidance describes a "butt-up" or nesting method for strip shingles: old ridge caps are removed, edges are trimmed and fitted with new metal edging, and each new shingle is pushed up against the butts of the old course so the new roof lies flat. Nails must be long enough to pass through both layers into the deck.

## Pros and cons

| | Tear-off | Overlay |
|---|---|---|
| Deck inspection | Full | Not possible |
| Flashing renewal | Straightforward | Often compromised |
| Weight | Lower | Higher |
| Cost and waste | Higher | Lower |

Many manufacturers' warranties and high-wind programmes favour or require a tear-off. A tear-off also allows the deck to be re-nailed and sealed. Overlays are mainly used for asphalt shingles and for some low-slope and metal recover systems designed for that purpose.

## Sources

1. Can you put new shingles over old shingles under IRC 2021? — Jaspector. https://www.jaspector.com/codes/irc-2021/ch09-roof-assemblies/reroofing-code-existing-shingles/
2. Roofing FAQs — City of Norman, Oklahoma. https://www.normanok.gov/sites/default/files/documents/2023-07/roofing_faqs.pdf
3. Reroofing — City of Bloomington, Minnesota. https://www.bloomingtonmn.gov/sites/default/files/2023-08/Reroofing.pdf
4. Canadian Roofing Reference Manual: 9.1.3 Overlaying an Existing Roof — Canadian Roofing Contractors Association. https://roofingcanada.com/docs/canadian-roofing-reference-manual/chapter-9-steep-slope-roofing/9-1-asphalt-shingles/9-1-3-overlaying-an-existing-roof/
5. Reroofing (2018 IRC R908) — City of Gillette, Wyoming. https://gillettewy.gov/files/assets/public/v/1/development-services/documents/reroofing-2018.pdf