Visible Signs Your Roof Needs Professional Cleaning
The clearest sign is visible biological growth: dark streaking, greenish patches, or fuzzy growth on tile surfaces. In Arizona, this appears most prominently on north-facing roof slopes that receive less direct sunlight and retain moisture longer after monsoon events. What looks like dark staining from the ground is almost always algae, lichen, or moss.
White or chalky spots on tile roofs indicate efflorescence — mineral deposits migrating from tile or mortar. Efflorescence indicates moisture cycling within the roofing system and should be addressed.
Less Obvious Signs to Watch
Grit or granule material in gutters after monsoon events indicates roof surface degradation. For tile roofs, chalky material in gutters suggests mortar deterioration. For shingle roofs, granule loss is a direct indicator of shingle aging.
Increasing HVAC costs with no clear cause can indicate that an algae-covered roof is retaining heat differently than a clean roof. Light-colored tile reflects significantly more heat when clean versus when coated with dark biological growth.
When to Inspect vs. When to Clean
Ground-level visual inspection is adequate for identifying obvious biological growth and discoloration. If you can see streaking, greenish patches, or discoloration on north-facing slopes, professional cleaning is needed.
Professional assessment provides a more complete picture — identifying cracked or displaced tiles, deteriorated mortar, and biological growth in valleys not visible from the ground. Blues Home Services includes a visual assessment during all roof cleaning visits.