Prescott has 250+ homes on the National Register of Historic
Places, mostly in the Mt Vernon, Capitol Hill, and East Prescott
historic districts. Many of these homes have original cedar shake
roofs, which:
- Are Class C fire rating (lowest of three)
- Are required to be preserved or matched under the historic
preservation overlay
- Live in a city now in WUI fire-zone classification
The two rules are in tension. Here's how Prescott resolves it as
of April 2026.
Three legal paths to keep cedar shake
- Cedar shake with intumescent fire-retardant treatment.
Approved chemical treatments (Cedarbrite FR, Westshield FR)
upgrade cedar shake from Class C to Class B. Treatment lasts
8-12 years before re-application. Cost: ~$2,500-$4,000 on a
typical historic home.
- Class A simulated cedar shake. Composite shingles that look
like cedar shake but pass UL 790 Class A. DaVinci Roofscapes,
Brava Roof Tile. Cost: $24-$32/sq ft installed, vs $14-$18
for asphalt or $9-$13 for traditional cedar.
- Variance through Prescott Historic Preservation Commission.
File for a "preservation hardship" — allows continued cedar
shake without treatment if the home is on the National
Register. ~3-month review process.
What's NOT allowed in 2026
- Untreated cedar shake on new construction or major repair in
WUI zones. Even on historic homes, untreated cedar shake fails
to meet IBC 2024 Section 705.6.
- Shake-look composite without UL 790 cert — asphalt 3-tab
"cedar look" shingles don't qualify as historic-matching.
- Cedar shake without 1/8" mesh attic ventilation — embers
can pass 1/4" mesh and ignite from below.
Insurance impact
Even if your cedar shake is legal, insurance carriers may:
- Refuse to write a new policy
- Charge a 30-50% wildfire-exposure surcharge
- Require an annual inspection + maintenance log
Treated cedar shake gets a moderate surcharge (~10-20%); composite
shake gets the standard rate.
The math: keep vs replace
| Path | 30-yr total cost | Resale impact |
|------|-----------------|---------------|
| Treated cedar shake | $26K (incl. 2 retreats) | Preserves historic value |
| Composite shake | $48K (initial) | Modest premium |
| Asphalt (with variance) | $32K (1.5 re-roofs) | Reduces historic value |
For homes on the National Register, the historic-value preservation
of treated cedar shake usually wins financially.