Roof cleaning, algae, moss, and debris

Normal function

Cleaning keeps inspection lines visible, reduces debris/moisture retention, and can improve appearance. It does not restore worn shingles or repair a leak.

What a homeowner may notice

• Black streaks, green growth, moss clumps, leaf mats, branches, or debris concentrated in valleys and shaded slopes.
• Lifted shingle edges under moss or damp debris.
• Granules collecting in gutters or bare shingle patches after aggressive cleaning.
• Plant damage or runoff staining from an uncontrolled treatment.

Professional inspection

Identify roof material, age, pitch, access, biological growth type, gutter condition, and nearby landscaping. Photograph before treatment and check for pre-existing granule loss or fragile shingles.

Repair or replacement path

Use low-pressure, material-compatible cleaning or treatment, protect vegetation, manage runoff, and follow the product label and manufacturer instructions. ARMA and manufacturers caution against power washing, abrasive brushing, and aggressive scrubbing of asphalt shingles.

Typical materials and equipment

Low-pressure sprayer, compatible labeled treatment, plant covers/rinse water, fall protection, debris bags, gutter guards or screens only if appropriate, and cleanup tools.

When to act

Remove heavy debris promptly. Routine cleaning is maintenance; do not clean a brittle roof in a way that causes granule loss.

What moves the price

Roof material and age, pitch, moss density, landscaping, runoff controls, height, access, repeat treatment, and manufacturer warranty.