Press on the deck around the leak. Firm? Clean, dry, detail-coat the failed area, and coat the roof. Spongy? The plywood is wet — repair the deck first, then coat. Sealing water inside a roof cavity is the one mistake you cannot undo cheaply.
No — remove only what is loose or flaking. Sound old sealant gets detail-coated over at heavy build. That is one of the biggest labor savings versus a tear-off style redo.
You can, and it beats doing nothing, but the field is where oxidation and pinholes happen next. Seam-only jobs are why we see the same roofs twice. The whole-roof price difference is usually two gallons.
Wash and prep one afternoon, detail-coat and first field coat the next morning, second coat after the 6-hour recoat window. A committed weekend for a typical camper, with rain-safe film 4 hours after each coat at 70°F.
Fresh lap sealant buys 2–4 years per joint, forever. The membrane is a 10-year-plus surface that renews with a single wash-and-recoat — no stripping. Over a decade you touch the roof once instead of five times.
Wait for a 50°F+ window with a dry roof and no dew before the film skins (2–3 hours). Cold does not ruin the coating in the pail — it just stalls the cure on the roof. If winter beats you, tarp the camper and do it right in spring.
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