Roof Cleaning Cost Calculator

What this calculator estimates

This calculator quotes the all-in service price for a residential roof cleaning in 2026 US dollars. It covers the four cost components that real contractors invoice:

• Roof cleaning — base per-square-foot rate by method (soft wash, pressure wash, manual hand-scrub) × moss-level multiplier × material multiplier × pitch multiplier × storey multiplier × access multiplier.
• Gutter add-on — flat fee when bundled with the cleaning visit.
• Moss / algaecide treatment — chemical applied during or after wash to kill algae and slow regrowth.
• Post-cleaning sealant — optional protective coating that extends time between cleanings.

A minimum service-call floor of $325 applies in most US metro markets. Even a small detached cottage roof carries that minimum because mobilizing chemicals, soft-wash rig, and a 2-person crew is the dominant cost.

How to use it

1. Measure your roof area. Use Google Earth’s measure tool or pull from your most recent roof inspection report. A 1,500 sq ft single-storey ranch typically has a 1,750–1,950 sq ft roof area (after pitch adjustment). A two-storey 2,400 sq ft colonial usually has a 1,400–1,800 sq ft roof footprint.
2. Pick the method. Soft wash is mandatory for asphalt shingles. Pressure wash is fine on metal and some tiles. Manual scrub is the gentle choice for slate, cedar, and historic terracotta.
3. Set the material. Tile, slate, and cedar carry a 15–35% surcharge over asphalt because of breakage risk and walking technique.
4. Set pitch. Walkable (4/12 to 7/12) is baseline. Steep (8/12 to 10/12) requires roof anchors and rope access. Extreme (11/12+) typically needs scaffold or lift.
5. Set storey count. The labor multiplier is 1.0× for single-storey, 1.20× for two-storey, and 1.50× for three-storey or higher.
6. Set access difficulty. Easy means driveway proximity. Difficult means full scaffold required, fenced gardens to navigate, or pools and HVAC under the eaves.
7. Pick moss level. Light streaking is the most common starting point. Moderate or heavy moss adds 20–55% to the labor and chemical load.
8. Toggle add-ons. Gutter clean, moss treatment, sealant, and weekend premium adjust the total.

Typical 2026 US roof cleaning cost ranges

These ranges reflect 2026 nationwide pricing pulled from HomeAdvisor, Angi True Cost Report, and Q1 2026 contractor quotes from major US metros.

Pricing assumes a 2-person crew, no add-ons, walkable pitch, and asphalt or stated material. Add $145–$215 for a bundled gutter clean and $0.18 per sq ft for a long-acting algicide treatment.

Cost drivers

Cleaning method. Soft wash carries higher per-foot pricing than pressure wash because of chemical cost and dwell time, but it’s the only ARMA-approved method for asphalt shingles (TIB-200). Pressure wash is faster and cheaper but voids most US shingle warranties from GAF, Owens Corning, CertainTeed, and Atlas.

Moss / algae level. Light streaking is mostly a single soft-wash pass. Heavy moss mats require pre-treatment dwell (24–48 hours), a hand-removal pass with soft brush or low-pressure rinse, and a follow-up biocide application. The labor difference between light and heavy is roughly 55%.

Roof material. Asphalt shingle is baseline. Concrete and clay tile (+15%) require careful walking and tile-replacement budget for breakage. Metal is 10% cheaper because the surface accepts pressure wash safely. Slate is 35% premium because of breakage risk — a single broken slate is $45–$85 in materials plus labor. Cedar carries a 25% premium because of the manual brushing required to avoid raising the wood grain.

Pitch. Walkable (4/12–7/12) is baseline. Steep (8/12–10/12) typically adds 30% because crew must use rope access and roof anchors. Extreme pitch (11/12+) adds 65% and frequently requires scaffold rental ($150–$400/day) or a powered lift ($350–$700/day).

Storey count. Single-storey eaves are 8–10 feet up. Two-storey are 18–22 feet up — a 32-foot extension ladder, OSHA-compliant fall protection (29 CFR 1926.501), and longer chemical hose runs add 20% to labor. Three-storey requires roof anchors or scaffold and adds 50%.

Access difficulty. A roof bordered by mature landscaping, fenced rear yards, or aboveground pools adds 25% to the crew time. Some contractors decline jobs entirely when a single side is fully blocked.

Weekend and after-hours work. Saturday is roughly 15% premium; Sunday and holidays 20–25%; emergency or post-5pm work runs 35–50%.

Geographic spread. California, Pacific Northwest, and Northeast are 15–25% above the national median. Southeast is 10–15% below. Texas, Midwest, and Mountain states are within 5% of the median.

US codes and standards

US roof cleaning is governed by:

• ARMA Technical Bulletin TIB-200 — soft wash is the only approved cleaning method for asphalt shingles. Pressure washing voids most shingle warranties.
• NRCA Architectural Manual — recommends documented periodic cleaning to preserve warranty coverage.
• OSHA 29 CFR 1926.501 — fall protection required for any work above 6 feet, including most two-storey roof cleaning.
• EPA chemical guidance — sodium hypochlorite roof cleaning solutions must be diluted to under 3% active strength when applied near soil and waterways.
• State licensing boards — most states do not require a specific roof-cleaning license, but general contractor licenses, business insurance, and worker’s comp are universal contractor-rating signals.

Soft wash chemistry — what’s actually happening

The standard soft-wash mix is 50% sodium hypochlorite (12.5% strength bleach) diluted to 3:1 with water, plus a non-ionic surfactant (0.5–1% by volume) to break surface tension and help the solution cling to vertical surfaces. Total active chlorine on the roof is roughly 1.5–3%, dwelled for 10–20 minutes, then rinsed.

The chemistry kills:

• Gloeocapsa magma — the cyanobacteria responsible for the black streaks on Southeastern asphalt roofs. The kill happens in under 5 minutes of contact.
• Moss (Bryum, Tortula species) — the soft-wash kills the active growth; full removal of the dead mat happens with subsequent rain over 2–4 weeks, or with a soft-brush hand pass.
• Lichen (crustose and foliose) — the chemistry kills the symbiotic algae component, but the fungal mat takes 6–12 months to wash away naturally.

The rinse should be high-volume low-pressure (under 100 psi) — never a pressure-washer tip on an asphalt roof.

When to clean vs when to replace

Cleaning extends the visual life of a roof but doesn’t fix structural problems. Replace instead of clean when:

• More than 15% of shingles show curl, cracking, or granule loss revealing the asphalt mat.
• Moss has lifted shingle edges (visible gap when viewed from below at the eave).
• The deck shows soft spots or sag visible from inside the attic.
• The roof is past 80% of its rated lifespan (typically 20+ years for 3-tab, 22–25+ years for architectural shingle).

Pair with our roof replacement cost calculator to compare cleaning ($475–$925) vs replacement ($8,500–$22,000) economics.

Avoiding scams and overcharging

The roof cleaning market has door-knocker fraud after major storms or visible algae outbreaks. Red flags:

• Pressure to sign before you’ve reviewed a written quote.
• “Free inspection” claims followed by urgent damage findings.
• Cash-only or wire-transfer demands.
• No state contractor license number on the proposal.
• Up-sell to “complete roof replacement” without a written diagnostic.
• Pressure washing offered for asphalt shingles (this voids your warranty).

Insist on a written estimate with: square footage assumption, method (soft vs pressure), chemistry summary, plant-protection plan, and proof of $1M+ general liability insurance. If the contractor refuses to share insurance, walk away — a chemical-burn lawn or a fall on uninsured contractor at your home becomes your homeowner’s-insurance liability event.

Related calculators and guides

• Gutter cleaning cost calculator — bundle for $145–$215 add-on
• Roof coating cost calculator — when post-cleaning sealant becomes a full restoration
• Roof replacement cost calculator — when cleaning reveals end-of-life conditions

Sources: 2026 HomeAdvisor Roof Cleaning Cost Guide; Angi 2026 True Cost Report; ARMA Technical Bulletin TIB-200; NRCA Architectural Manual; OSHA 29 CFR 1926.501; CPSC ladder-injury statistics 2024; EPA sodium-hypochlorite use guidance.