Roof Decking Repair

Eaves. By far the most common rot zone on NJ roofs. Caused by ice-dam meltwater backing up under shingles on roofs without code-compliant ice & water shield (NJ R905.1.2 requires 24" past the inside wall plane). Older NJ homes (pre-2000) almost universally have eave decking rot to some degree.

Valleys. Open-metal valleys can leak at fasteners; closed-cut valleys can leak through the lap seam. Rot follows the valley line down to the eave.

Around chimneys. Specifically behind the chimney, where the cricket/saddle should be but often isn't on NJ chimneys over 30" wide. Water pools behind the chimney, finds its way through failed step flashing or counter flashing, and rots the deck.

Around skylights. The uphill side of the skylight curb is the failure zone — flashing fails, water backs up, decking rots within 3-4 feet of the skylight.

Pipe penetrations. Where the original pipe boot has cracked from UV. Water runs down the pipe and into the deck around the boot opening.

Wall intersections (where the roof meets a vertical sidewall, on dormers, second-story additions, etc.). Failed step flashing lets water in behind the siding, where it rots the deck along the wall line.

Vent penetrations. Bathroom and kitchen exhaust vents that vent into the attic rather than to the exterior cause condensation that rots deck under the vent location.

During tear-off, every sheet gets probed with a screwdriver or awl. Sound plywood resists the probe; rotted plywood lets the tool sink in. We mark every section that fails the probe test with chalk before deciding cut lines.

Replacement cuts get squared to the nearest framing member so we land all the edges on solid framing (rafters or trusses). This is the difference between a code-compliant repair and a quick patch. NJ Uniform Construction Code requires all panel edges to be supported.

New decking matches existing thickness (typically 1/2" CDX plywood or 5/8" CDX plywood — never OSB for replacement on a rotted area; OSB doesn't accept water as forgivingly as plywood and complicates future inspections).

Nail pattern per code: 8d common nails, 6" on center at panel edges, 12" on center in the field (per NJ Uniform Construction Code and IRC R803.2.3). This is the spacing that resists wind uplift; production crews often skip this, especially on the field nailing.

Every replaced section gets photographed before the new underlayment goes down — photos delivered to the homeowner as part of the final job documentation. This protects both parties on warranty and resale.

After decking replacement, the cause of the rot gets addressed too — new ice & water shield at eave rot zones, new flashing at chimney/skylight rot zones, new pipe boots at penetration rot zones. Otherwise the deck rot just comes back.

Per-sheet pricing. Every quote we issue includes a per-sheet decking allowance — typically based on 1/2" CDX plywood at full sheet size (4×8). The homeowner sees the rate in writing before tear-off and pays exactly that rate × the number of sheets actually replaced.

Smaller patches (less than a full sheet) get charged at half-sheet or quarter-sheet rates depending on size. We don't charge full-sheet rates for patches — the homeowner only pays for the actual material used plus the labor.

Major structural rot (multiple sheets, rotted rafter ends, or signs that the original framing has failed) becomes a separate scope. We stop work, document the conditions, and provide a written change-order with the homeowner's approval before continuing. This is rare — most NJ residential roofs have surface-level deck rot, not structural framing rot.

Sheathing upgrade from OSB to plywood. Some homeowners ask for plywood replacement of OSB during a re-roof. We can do it, but it's a separate line item from rot repair — full re-sheath at a per-sheet rate × every sheet of the roof.