If your HOA or condo board sent a letter about roof staining, it's almost certainly Gloeocapsa magma — a wind-borne algae, not dirt — and the fix is a soft wash, not a re-roof. Only 24.37% of Altamonte Springs' roughly 20,871 housing units are single-family detached; the rest are apartments, condos and townhomes governed by boards that enforce uniform curb appeal, which is why these notices are common here.
Altamonte Springs is denser and more condo/townhome-heavy than the towns around it, and 75.3% of its housing stock was built between 1970 and 1999 — old enough that most roofs have had years of uninterrupted algae growth. A board enforcing community standards is going to flag the roof that stands out, and in a community with shared rooflines or a uniform appearance requirement, one visibly streaked roof reads as a maintenance failure even when it's purely cosmetic.
They're almost always Gloeocapsa magma, a wind-borne cyanobacterium (often called “algae”) that colonizes roofs in warm, humid climates and appears as dark streaks or stains, usually starting on the north- or shade-facing slope. It feeds on the limestone filler in asphalt shingles and on tile grout and glaze, and it spreads from roof to roof on the wind, which is why entire blocks in the same subdivision tend to stain around the same time.
Central Florida's combination of sustained heat, humidity and shade is exactly what Gloeocapsa magma needs to establish itself and spread — it's a biological growth, not dirt, soot or a manufacturing defect. Roofs under mature tree canopy or near a lake dry out more slowly after rain, which extends the daily window the algae has to feed and multiply, so shaded and lake-adjacent roofs typically streak first and worst.
Sabal Point's mandatory HOA (Sabal Point Community Services Association) requires prior written Architectural Review Committee approval before any change to exterior roofing materials, and the neighborhood backs onto the Wekiva River Buffer Preserve and the 2,500+ acre Charles Lee Sabal Point Sanctuary — denser, more mature tree canopy than the citywide average, which slows roof drying and speeds up algae and moss growth. A routine soft wash changes no material, so it's a different track from an ARC-approval request, but if your board wants it on file, ask your property manager what documentation they expect and we'll provide before/after photos and an invoice to match.
Routine roof cleaning is a different track from a permitted roofing project. The City of Altamonte Springs Building and Fire Safety Division's permit FAQ addresses roof replacement and repair, not exterior cleaning, and lists cosmetic work like painting as not requiring a permit — but it doesn't explicitly rule cleaning in or out either way. If your board wants that confirmed in writing, call the division directly at 407-571-8433.