Cedar shake roof replacement is governed by two non-negotiable factors: cedar is torn off to the deck rather than roofed over, and untreated cedar carries no fire rating on its own. N.J.A.C. 5:23-6.4 prohibits roofing over wood shake, and UL 790 leaves untreated cedar nonclassified.
Both the tear-off requirement and the fire-class limit set the terms before a homeowner chooses cedar, and the ventilated nailing base then governs how long the new cedar lasts.
Why Must a Cedar Roof Be Torn Off to the Deck?
A new cedar roof cannot go over an old cedar roof, because N.J.A.C. 5:23-6.4 prohibits roofing over wood shake and over a water-soaked or deteriorated deck, so a cedar replacement requires a full tear-off to the bare sheathing. The NJ Rehabilitation Subcode expressly lists wood shake among the coverings that cannot be recovered, unlike the model IRC R908.3.1.1, per the NJ Uniform Construction Code.
The tear-off exposes the deck for inspection and repair, which is the practical reason the code rule matters to a homeowner. Years of trapped moisture beneath the old cedar rot the plywood or OSB sheathing, and a full strip lets the contractor replace deteriorated decking before the new cedar goes down, per N.J.A.C. 5:23-6.4. Tear-off and deck repair add cost to a cedar replacement as a result.
Permitting follows the building type under N.J.A.C. 5:23-2.7. A complete tear-off and replacement of the roof covering on a detached one- and two-family dwelling counts as ordinary maintenance and requires no construction permit, no inspection, and no notice to the construction official, per the NJ Uniform Construction Code. A commercial cedar roof or a structural change to rafters or trusses still triggers a permit, because the commercial ordinary-maintenance exemption covers only repair of up to 25% of total roof area in a 12-month period.
What Fire Class Does Cedar Carry?
Untreated cedar shakes and shingles are nonclassified on their own under UL 790 and ASTM E108, the roof-covering fire-test methods, so the fire performance of a cedar roof is a material trade-off a homeowner weighs before choosing the wood. Pressure-impregnated fire-retardant cedar carries a Class B or Class C product class, per the Cedar Shake & Shingle Bureau Certi-Guard program.
A Class A wood roof is an assembly rating, not a property of the shake itself. The top fire class is achieved only as a tested assembly of fire-retardant shakes installed over a fire-retardant cap sheet, per the Cedar Shake & Shingle Bureau Certi-Guard program and InterNACHI, not from the wood covering alone. Fire-retardant-treated cedar adds the pressure-impregnation cost over untreated cedar, per Cedar Shake & Shingle Bureau material guidance.
How Long Does a New Cedar Roof Last?
A cedar roof's service life depends on a ventilated nailing base and on moisture management, because moisture-driven cupping, splitting, and rot end most cedar roofs. Cedar shake lasts 20 to 40 years and cedar shingle 30 to 50 years, per the Cedar Shake & Shingle Bureau, with the InterNACHI life-expectancy chart listing wood at 25 years and maintenance setting where in the range a cedar roof lands.
The ventilated nailing base governs the outcome, holding at least 1.5 inches of drying air space beneath the shakes, per Cedar Shake & Shingle Bureau install guidance. That airflow extends cedar service life and slows the moisture cycling that degrades the wood faster on north-facing and shaded slopes. Newark crosses the 32 degree F freezing point repeatedly through winter with an average January low near 25.5 degrees F, per NOAA 1991-2020 normals at Newark Liberty (EWR), and that freeze-thaw load drives the cupping and rot a wood roof faces.
What Should You Verify in a Cedar Contractor?
Confirm the contractor holds New Jersey Home Improvement Contractor registration under N.J.S.A. 56:8-136 — a registration, not a license, because New Jersey issues no roofing license. The 13VH registration number appears on the contract and advertising per N.J.S.A. 56:8-144. Verify $500,000-per-occurrence commercial general liability coverage required by N.J.S.A. 56:8-142 by a certificate of insurance before any tear-off begins.
Require a written contract and an itemized estimate, mandated for any home-improvement work over $500 under N.J.A.C. 13:45A-16.2, that sets scope, labor, materials, and timeline and presents the cedar selection by type and fire class in writing. Ask for a written workmanship warranty on the labor, separate from the manufacturer material warranty on the cedar, which preserves factory-defect coverage when the wood is installed to specification, per Cedar Shake & Shingle Bureau guidance.
Before choosing cedar, a homeowner weighs three things the code and the material set: the cedar gets stripped to the deck under N.J.A.C. 5:23-6.4, untreated cedar carries no fire rating while fire-retardant cedar reaches only Class B or C as a product per the Cedar Shake & Shingle Bureau Certi-Guard program, and the ventilated nailing base governs how long the new wood lasts.