The roof was replaced to stop attic mold. Five years later the mold is back and the roofer admits a vent error

The owner described the dispute on Reddit's r/Roofing, asking whether demanding a new roof is fair and whether a lawyer is needed. The details come from the owner's post; the roofer's side is not public.

The International Residential Code requires 1 square foot of net free vent area for every 150 square feet of attic floor, or 1 per 300 when 40 to 50 percent of it sits within 3 feet of the ridge and the rest low in the attic. Intake should always equal or exceed exhaust, GAF codes manager Joan Crowe wrote for IIBEC; otherwise the attic can draw warm, moist house air through can lights and hatches. GAF's product literature says ridge exhaust should never exceed soffit intake. Crowe's example of the common error: a new ridge vent on a house with no working soffit vents.

Whether the sheathing has to go depends on its condition. OSHA says wood and other semi-porous materials that remain structurally sound can be cleaned, while porous ones such as insulation are usually removed after long wetting. The EPA says mold covering more than about 10 square feet calls for its commercial remediation guide and a contractor experienced with mold, and warns against painting over growth without cleaning it first.

That gives the owner a test. An independent inspector can probe the deck and nails, measure intake and exhaust against the 1/150 or 1/300 rule, and price any board replacement separately. Soft or delaminated sheathing gives the owner a documented reason to ask the roofer to pay for new decking; sound boards point to cleaning plus a balanced vent system, which is what the roofer has offered.