What Should You Know About Re-Roofing Roofing?

Code, not budget, sets the outer limit on a recover. A roof-over is prohibited where the existing roof is water-soaked or deteriorated, where the covering is wood shake, slate, clay, cement, or asbestos-cement tile, or where two or more applications already exist, per N.J.A.C. 5:23-6.4 and IRC R908.3.1.1.

A full tear-off strips the covering to the deck. That exposes the roof deck for inspection, lets a contractor repair damage and improve deck attachment to the structure, and catches deck rot and water damage a recover hides, per ARMA and InterNACHI. A recover installs a new layer over the existing single sound layer without that view of the sheathing.

The condition of the deck decides the question on a single-layer roof. Where the deck is sound and only one layer exists, a recover is allowed; where the deck is water-soaked or deteriorated, complete removal is required, per N.J.A.C. 5:23-6.4. The deck assessment, not the lower quote, governs which path the code permits.

A recover skips tear-off labor and disposal, which makes it cheaper, but the savings come with hidden costs. A recover runs roughly 20 to 25 percent less than a full tear-off, about $2,000 to $5,000 cheaper on national figures, per HomeGuide and Angi.

Those savings buy several long-term penalties. A recover over a single sound asphalt layer traps heat that industry estimates cut shingle service life by roughly 20 to 30 percent, so a 25-year shingle may deliver only about 17 to 20 years, per Angi and ARMA. It also hides deck rot a tear-off would catch and resolve.

A second layer adds dead load and a costlier future. A second overlay layer adds roughly 2 to 4.5 pounds per square foot of dead load — thousands of extra pounds across deck, rafters, and walls — telegraphs the old shingle profile through the new cover, and forces a costlier future double tear-off, per Angi and converted per-square shingle-weight data.

A complete re-roof of the covering on a detached one- and two-family home counts as ordinary maintenance and requires no construction permit. That classification falls under N.J.A.C. 5:23-2.7 of the NJ Uniform Construction Code, while a structural change to rafters or trusses still triggers a permit.

A commercial re-roof does require a permit. The ordinary-maintenance exemption covers only the repair of up to 25 percent of the total roof area in a 12-month period, so a full commercial re-roof exceeds it and needs a permit, per N.J.A.C. 5:23-2.7. An ice barrier is installed from the eave to a point at least 24 inches inside the exterior wall line on either building type, per IRC R905.1.2.

Confirm registration, insurance, and a written, itemized contract before any tear-off begins. Verify New Jersey Home Improvement Contractor registration under N.J.S.A. 56:8-136, with the 13VH number on the contract and any advertisement per N.J.S.A. 56:8-144 — a registration, not a roofing license, because New Jersey issues no roofing license.

Two further checks protect the homeowner financially. Confirm at least $500,000 per-occurrence commercial general liability coverage required under N.J.S.A. 56:8-142, verified by a current certificate of insurance, and require a written contract for any job over $500 under N.J.A.C. 13:45A-16.2, with scope, total price, and start and completion dates set in writing before work begins.

An itemized estimate and a two-part warranty round out the verification. Require an estimate that lists tear-off, deck repair, ice barrier, underlayment, the cover, disposal, and the permit when one is triggered, so nothing is silently excluded. Installing the cover to manufacturer specification preserves the manufacturer material warranty on factory defects, separate from the contractor's written workmanship warranty on the labor, per Owens Corning warranty guidance.