Roof overlay vs tear-off (2026):
cost, code limits in Washington and which to choose
HOW MUCH DOES A ROOF TEAR-OFF COST?
HomeGuide puts tearing off an asphalt shingle roof at $1 to $3 per square foot, on top of the new roof, or $3 to $6 per square foot for tear-off and replacement together. An overlay skips the tear-off, so it's cheaper and faster, but HomeGuide says it shortens the roof's lifespan. Washington's residential code doesn't allow an overlay over two or more existing layers, or over a water-soaked or deteriorated roof.
Overlay vs tear-off, side by side
| Overlay (roof-over) | Tear-off and replace | |
|---|---|---|
| What happens | New roofing goes on top of the existing roof | Old roofing is removed down to the decking, then a new roof goes on |
| Cost | Less expensive | More expensive |
| Time | Faster and easier | Takes longer |
| Lifespan | Shorter | Longer |
| Structure | Extra weight; the roofer can't examine the decking | Decking can be inspected and repaired |
| Flashing | May be compromised | Replaced with the new roof |
An overlay leaves any rotten decking hidden under the new roof. If you're unsure what's under your shingles, a tear-off is the only way to see. Our guide on how to read a roofing estimate explains the decking line.
When an overlay isn't allowed in Washington
Washington adopts the 2021 International Residential Code (IRC), with state amendments, for houses (WAC 51-51-003). IRC section R908.3.1.1 says a roof recover is not permitted where:
- The existing roof is water-soaked or has deteriorated so it's not an adequate base for more roofing.
- The existing roof covering is slate, clay, cement or asbestos-cement tile.
- The existing roof already has two or more layers of any type of roofing.
IRC R908.4 adds that a new roof over wood shingles or shakes that creates a combustible concealed space needs the whole existing surface covered with gypsum board, mineral fiber, glass fiber or another approved material first. For Seattle permits, SDCI says re-roofing one- and two-family homes doesn't need a permit if no changes are made to the building envelope other than adding or replacing insulation.
Tear-off cost by roof type
| Roof | Tear-off only, per sq ft | Tear-off and replace, per sq ft |
|---|---|---|
| 3-tab asphalt shingles | $1–$3 | $3–$5 |
| Architectural shingles | $1–$3 | $4–$6 |
| Metal | $1–$3 | $5–$16 |
| Wood shakes | $1–$2 | $7–$15 |
| Tile | $2–$5 | $7–$25 |
| Slate or stone | $2–$5 | $10–$30 |
| Flat | $1–$2 | $3–$11 |
Example: tear-off on an average Seattle roof
| Step | Amount |
|---|---|
| 1,800 sq ft roof (Angi's Seattle average) × $1–$3 tear-off (HomeGuide, asphalt) | $1,800–$5,400 |
| With Seattle's 10.55% sales tax | $1,990–$5,970 |
An overlay saves roughly this amount up front. Whether that's worth a shorter roof life and no look at the decking depends on your roof's condition and how long you'll stay. To price the full job, use our roof replacement cost calculator.
Before you sign
- Ask how many layers your roof has now. With two or more, an overlay isn't allowed under IRC R908.3.1.1.
- If a roofer proposes an overlay, ask how they checked the decking for rot and soft spots.
- Ask whether the flashing will be replaced or reused.
- Look the roofer up on L&I's Verify a Contractor tool. For jobs of $1,000 or more on a home, the contractor must give you a written disclosure statement before work starts (RCW 18.27.114).
Frequently asked questions
How much does a roof tear-off cost?
HomeGuide lists $1 to $3 per square foot to tear off asphalt shingles, and $2 to $5 for tile or slate. For a 1,800 sq ft roof, that's about $1,800 to $5,400 for asphalt, before tax.
Can you put a new roof over an old one in Washington?
Sometimes. Washington uses the 2021 International Residential Code, which doesn't allow a roof recover over two or more existing layers, over slate or tile, or over a water-soaked or deteriorated roof.
Is a roof overlay a good idea?
HomeGuide says an overlay is cheaper and faster but shortens the roof's lifespan, adds weight, may compromise flashing and stops the roofer from examining the structure.
How many layers of shingles are allowed?
HomeGuide says most states allow a maximum of two. Under the code Washington uses, a recover isn't allowed if the roof already has two or more layers.
Do I need a permit to re-roof in Seattle?
SDCI says re-roofing one- and two-family homes doesn't need a permit if no changes are made to the building envelope other than adding or replacing insulation. Other cities have their own rules; see roof permit rules by city.
Need a repair instead of a new roof? See roof repair cost by type of repair, or roof leak repair cost if water is already coming in.
Sources
- HomeGuide — Average Cost to Tear Off and Replace a Roof (November 7, 2025)
- International Code Council — 2021 IRC, Chapter 9 Roof Assemblies (R908.3.1.1, R908.4)
- WAC 51-51-003 — Washington adoption of the International Residential Code
- Seattle SDCI — Re-Roof Permit
- Angi — Roof replacement cost in Seattle, WA (updated Aug 4, 2026)
- Washington Department of Revenue; RCW 18.27.114; L&I — Hiring a contractor
All sources accessed October 15, 2026.
This guide summarizes published cost estimates and code provisions. It is not legal advice and not a quote; local amendments and permit rules vary. Get written estimates from licensed, bonded and insured roofers before deciding. See our disclosure and disclaimer.