Roof Cleaning

A Clean Roof Lasts Longer and Looks Better

Roof cleaning is not cosmetic — it is maintenance. Algae, moss, lichen, and debris degrade roofing materials over time. Black algae streaks absorb heat and shorten shingle life. Moss lifts shingle edges and forces water underneath. Debris clogs gutters and traps moisture against the roof surface. A clean roof sheds water properly, reflects heat evenly, and resists weather damage longer.

We soft-wash roofs using low-pressure chemical treatment that kills organic growth at the root without damaging shingles, tiles, metal, or membrane surfaces. High-pressure washing damages roofing materials — our method cleans thoroughly and protects the surface.

What Grows on Your Roof

The black streaks, green patches, and fuzzy growth on roofs are living organisms that feed on the roofing material.

• Algae (Gloeocapsa magma) — the black streaks on asphalt shingles; feeds on the limestone filler in shingles, causing granule loss and premature aging
• Moss — green, raised clumps that hold moisture against the roof; lifts shingle edges and forces water under the surface
• Lichen — white or light-green crusty patches that bond tightly to the roof surface; causes surface erosion and granule loss
• Mildew — thin, powdery fungal growth that appears in shaded areas; cosmetic but indicates moisture problems
• Debris — leaves, pine needles, and branches that trap moisture, clog gutters, and promote organic growth

These organisms thrive on north-facing slopes, shaded roofs, and areas with tree cover. They spread from roof to roof through airborne spores.

How We Clean a Roof

Our soft-wash method uses chemistry, not pressure, to clean the roof surface.

1. Preparation — we wet down surrounding landscaping, cover plants near the foundation, and protect sensitive surfaces
2. Application — a biodegradable cleaning solution is applied to the entire roof surface using low-pressure sprayers; the solution kills algae, moss, and lichen at the root
3. Dwell time — the solution sits on the surface for 10 to 15 minutes to break down organic growth
4. Low-pressure rinse — the roof is rinsed with low-pressure water (under 500 psi) to wash away dead organic material without damaging the shingles
5. Gutter flush — we flush the gutters and downspouts to clear any debris and solution residue
6. Final inspection — we verify the roof is clean, the landscaping is undamaged, and the gutters are flowing freely

We never use pressure washers on roofing materials. High pressure strips granules from shingles, cracks tile surfaces, and forces water under seams and flashing.

Roof Cleaning Costs

Service	Typical range
Soft-wash cleaning (up to 2,000 sq ft roof)	$300 – $600
Soft-wash cleaning (2,000 – 4,000 sq ft roof)	$500 – $1,000
Soft-wash cleaning (4,000+ sq ft roof)	$800 – $1,500
Moss removal (heavy growth)	$200 – $500 additional
Gutter cleaning (included)	Included with cleaning
Annual maintenance cleaning plan	$250 – $450 per visit
Solar panel cleaning (add-on)	$100 – $200

Cleaning costs depend on roof size, pitch, and the severity of organic growth. Heavily moss-covered roofs require more solution and dwell time.

How Often to Clean Your Roof

• Every 2 to 3 years — standard maintenance for most homes
• Every year — homes with heavy tree cover or persistent algae problems
• After a long period of neglect — roofs with heavy moss or lichen buildup may need two treatments to fully eliminate growth
• Before applying roof coating or sealant — a clean surface is required for proper adhesion
• After a storm — debris accumulation from fallen branches and leaves should be removed promptly

What NOT to Do When Cleaning Your Roof

• Do not use a pressure washer — high pressure damages shingles, strips granules, and forces water under the surface
• Do not use bleach at full strength — it kills organic growth but also damages shingles, discolors metal, and kills landscaping
• Do not walk on a wet roof — freshly cleaned roofs are slippery; leave the inspection and rinsing to professionals
• Do not ignore the gutters — cleaning the roof without cleaning the gutters defeats the purpose; the gutters must flow freely
• Do not use generic household cleaners — they are not formulated for roofing materials and can cause discoloration or damage

DIY vs. Professional Roof Cleaning

DIY may work when:

• The roof is low-slope and easily accessible
• Growth is light and limited to a small area
• You have proper safety equipment (harness, non-slip footwear)

Call a professional when:

• The roof is steep or more than one story
• Moss or lichen is widespread or heavy
• The roof has solar panels, skylights, or complex geometry
• You want a preventive treatment to suppress regrowth

Roof Cleaning by Material Type

Roof material	Safe cleaning method	Avoid
Asphalt shingles	Soft-wash with sodium hypochlorite solution	Pressure washing, granule-scraping
Metal roofing	Low-pressure rinse with mild detergent	Abrasive scrubbers, high-pressure washing
Clay tile	Soft-wash, hand removal of moss	Pressure washing (cracks tiles), harsh chemicals
Concrete tile	Soft-wash with algaecide treatment	Pressure washing (erodes surface)
Cedar shake	Low-pressure wash, moss hand-removal	Pressure washing (splits wood), bleach
Slate	Soft-wash only, gentle moss removal	Pressure washing (dislodges slates)
Flat membrane (TPO, EPDM)	Low-pressure rinse, manufacturer-approved cleaner	High pressure (damages seams)

Every roof material has a specific cleaning method that is safe and effective. Pressure washing is never appropriate for roofing materials — it strips protective coatings, damages surfaces, and forces water into places it should not be. We match the cleaning solution and method to your specific roof material.

Environmental and Safety Considerations

Our cleaning solutions are biodegradable and designed to break down quickly after use. We take specific precautions to protect your property and landscaping:

• Wet down all surrounding plants before applying cleaning solution
• Cover sensitive plants and flower beds near the foundation
• Rinse all vegetation after the cleaning is complete
• Contain runoff to prevent solution from entering storm drains
• Postpone cleaning if heavy rain is forecast within 24 hours
• Use only EPA-approved cleaning products
• Follow all local regulations regarding roof cleaning chemicals

In rare cases, sensitive plants near the roof line may show temporary browning from solution overspray. This typically resolves within a few weeks and does not cause permanent damage. We take every precaution to minimize impact on your landscaping.

Signs Your Roof Needs Cleaning

• Black algae streaks running down the roof surface, especially on north-facing slopes
• Green moss or lichen patches visible from the ground
• Debris accumulation in valleys, around skylights, and at the base of dormers
• Gutters clogged with granules, leaves, or organic material
• Dark discoloration on the roof surface that was not there before
• Neighboring roofs with visible algae streaks (spores spread from roof to roof)

Roof looking stained or covered in moss? Call us or request a free estimate — we will clean your roof safely with the soft-wash method and restore its appearance.