Re-Roof vs Roof-Over — When You Have to Strip in NAZ

"Roof-over" = installing new shingles over the existing layer

without stripping. Cheaper + faster, but not always legal in NAZ

+ not always advisable.

When roof-over is allowed

AZ IRC 2024 (adopted by both Yavapai + Coconino):

• Maximum 2 layers of asphalt shingle on residential roofs
• Existing shingles must be flat (not curling/cupping)
• Underlying deck must be sound (no soft spots)
• Existing flashing must be reusable

When roof-over is NOT allowed (always strip)

1. Tile roofs — tile is too heavy + too rigid for layering
2. Metal roofs — different fastener pattern + thermal expansion
3. Wood shake — fire-code requires strip + Class A
4. Roof already has 2 layers — can't add a 3rd
5. Visible deck damage — must inspect/repair underneath
6. Most Coconino County over 6,500 ft — county code requires

strip due to snow load

1. Flagstaff city limits — city code requires strip
2. Class 4 impact-resistant install — manufacturer requires

strip for warranty

1. Synthetic underlayment install — requires direct deck

contact

Cost difference

On a 2,200 sq ft NAZ home:

| Approach | Cost | Lifespan |

|----------|------|----------|

| Strip + new shingles | $14,800 | 22-26 years |

| Roof-over (2nd layer) | $11,400 | 16-20 years |

Roof-over saves $3,400 upfront but lasts 6+ years less. Math:

pays back at year 18 if your existing roof has 4+ years left.

Why most contractors prefer strip

1. Inspection of deck — catch rot/damage before it spreads
2. Proper underlayment — synthetic vs felt over old shingles
3. Better aesthetic — no double-thickness shadow lines
4. Warranty compliance — manufacturer warranties often require

strip

1. Snow shed — second layer creates ice-dam pockets at edges
2. Resale — single-layer roofs are valued higher in MLS data

Insurance treatment

Most AZ carriers don't differentiate roof-over vs strip on initial

underwriting, but they DO note it on the inspection report.

Roof-over claims often get reduced ACV due to "reduced expected

life."

Some carriers (State Farm, Farmers) charge a 5-10% surcharge for

roofs with 2 layers.

When roof-over actually makes sense

1. Existing roof is < 8 years old + still mostly intact
2. You're 5-7 years from selling and want curb appeal without

full investment

1. Strip-and-replace estimates are 2x your budget
2. You're in a non-snow-zone Yavapai location
3. Existing layer is verified single-layer (not already a roof-

over)

Match with a re-roof vs roof-over contractor →