The honest answer: not long. Here's why.
Within 24–48 hours: mold begins
Alabama humidity means mold can begin growing within two days of moisture exposure.
Within a week: insulation damage
Wet insulation loses its R-value and may need full replacement.
Within a month: deck rot
Soaked roof decking begins to lose structural integrity. Deck replacement adds significant cost to any future repair.
Within a season: drywall failure
Repeated cycles of wet/dry damage drywall, paint, and ceiling textures.
Bottom line
Tarp it now, repair it within the week. Waiting always costs more.
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