Framing and Deck Replacement on a Roof-Over Candidate
A contractor is evaluating a 1920s house for a tear-off and re-roof. During inspection, the contractor finds 2x4 rafters at 24 inches on center with a 14-foot span, a ridge board that is a 1x6, several rafters with splits at the birdsmouth, and deck boards that are 1x6 tongue-and-groove spaced with visible gaps. The homeowner wants architectural shingles. The contractor's salesman has already quoted the job based on square footage only, assuming the existing framing would be reused. The contractor observes a noticeable sag in the ridge line and a crack in the plaster ceiling below.
1. What structural concerns must be resolved before this roof can be re-roofed, and how should the contractor proceed?
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The 2x4 rafters at 24 inches on center spanning 14 feet are almost certainly undersized for the span and for the added dead load of architectural shingles; the sagging ridge and cracked plaster indicate deflection and possible structural distress. The 1x6 ridge board is not a structural ridge beam and provides no support. The contractor should stop and have a qualified person (engineer or licensed structural contractor) evaluate the framing. Options include sistering or replacing rafters, adding a structural ridge beam or purlins, and repairing split rafters. The deck boards with gaps and tongue-and-groove spacing may not provide a suitable nailing surface for shingles and may need overlay or replacement decking. The salesman's square-footage-only quote is not a valid basis for the job.
2. How should the contractor handle the contract and pricing given the discovered conditions?
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The contractor should not proceed under the original quote. Issue a written change order or revised proposal that separates the roofing scope from the structural repair scope, states that the structural work is required for a code-compliant installation, and prices it separately. Include a contingency for concealed conditions and a provision that work will not proceed until the structural repair is accepted. The contractor should document the existing conditions with photos and measurements and obtain the owner's written approval before ordering materials or starting tear-off. Proceeding on the original quote exposes the contractor to uncompensated work and liability for a roof that may not meet code.
3. What code and safety issues arise from the existing deck and framing during tear-off?
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The contractor must verify the deck can support workers and materials and provide fall protection (guardrails, personal fall arrest, or a safety monitor per the applicable fall protection standard) since this is a steep-slope roof. The deteriorated deck boards and split rafters create fall-through and collapse hazards; the contractor should stage materials to avoid overloading and inspect the deck as it is exposed. The new roof must meet current code requirements for deck attachment, fastener penetration, and, where applicable, ice barrier and underlayment. Any structural repair must be permitted and inspected if required by the local jurisdiction.