Roof Cleaning Cost

A professional roof cleaning costs $0.30–$0.75 per square foot for a soft wash, with most single-family homes landing between $300 and $700 total. That covers removing algae streaks, moss, and mildew from a 1,200–2,500 sq ft roof using low-pressure equipment and cleaning solutions — never a high-pressure blast, which strips shingle granules and voids warranties. Heavier moss, steep pitches, and two-story access push the price up; a simple rinse-and-treat on a small ranch roof can come in under $300.

2026 roof cleaning prices by method

Method is the single biggest price driver — and the single biggest quality divider. Here's what each approach costs and what it's actually doing to your roof.

Soft washing is low pressure (garden-hose levels) plus a sodium-hypochlorite-based solution with surfactant that kills algae, moss, and mildew at the roots and rinses clean. Pressure washing is cheaper because it's just water at high PSI — and it's the wrong tool for a roof. It dislodges the granules that protect asphalt shingles from UV, forces water under tiles and flashing, and gives manufacturers a reason to deny warranty claims. If a bid is suspiciously cheap, ask for the method in writing.

Roof cleaning cost by roof size

Roof square footage runs larger than your home's floor plan — multiply by 1.15–1.4 to account for pitch and overhang. These are 2026 US ranges for a professional soft wash:

Most contractors also charge a $100–$150 minimum to cover drive time and setup, so very small jobs (a dormer or a porch roof) price off the minimum rather than the per-foot rate. Steep pitches (8/12 and up), three-story access, and heavy moss add 25–50% on top.

What you're actually paying to remove

Three different organisms live on dirty roofs, and each wants a different level of treatment:

• Black streaks (Gloeocapsa magma algae): the most common roof problem in humid climates. Cosmetic at first, but algae feeds on the limestone filler in shingles and holds moisture against them. A standard soft wash kills it in one visit.
• Moss: thicker, root-like growth that lifts shingle edges and traps water underneath. Needs a biocide dwell treatment plus hand removal on severe patches — the $0.35–$0.70 tier. Scraping dry moss off shingles tears granules; it must be killed and loosened first.
• Lichen: the crusty, flat patches that bond directly to granules. The toughest to remove — it often needs a dedicated chemical treatment and a second visit after the colony dies and flakes off.

Cleaning solves the symptom, not the cause. Roofs under heavy tree cover in humid regions regrow algae in 2–3 years. Zinc or copper strips installed near the ridge release metal ions with every rain that inhibit regrowth — $200–$400 installed, and the closest thing to a long-term fix. Trimming back overhanging branches buys you as much time as any chemical.

Cost by roofing material

When cleaning isn't enough: repair vs. clean

Cleaning reveals problems — a good contractor tells you when what they found isn't a cleaning problem at all:

• Curling, cracked, or missing shingles: cleaning won't fix them. Budget for repairs or replacement instead of spending $600 on a roof that's at end of life.
• Granule loss in the gutters: piles of sand-like granules mean the shingles are wearing out. A wash makes it look better for a season; the roof still needs replacing soon.
• Soft or sagging decking: if the roof feels spongy underfoot, that's rot — stop and get a roofing estimate, not a cleaning quote.
• Active leaks or water stains: cleaning does nothing for leaks. Fix the leak first; clean after, so the new repair blends in.

Rule of thumb: if the roof is over 20 years old and showing wear, put the cleaning money toward replacement. Our roof replacement cost guide breaks down the real 2026 numbers.

DIY vs. hiring a pro

A single-story, low-slope roof is genuinely DIY-able: a garden hose, a pump sprayer, and an oxygen-bleach or roof-wash concentrate runs $50–$150 in materials for an average home — roughly a third of the pro price. Work on a cool, overcast day, spray from the ridge down, protect landscaping with tarps (runoff kills plants), and never use a pressure washer.

But the math changes fast with height. Falls are the leading cause of death in roofing work, and a steep or two-story roof has no safe DIY version. Hire a pro when: the pitch is 6/12 or steeper, the roof is two stories, there's heavy moss requiring chemicals you shouldn't handle, or the roof is old enough that walking it risks damage. A $500 pro visit is cheaper than one ER visit — and pros carry the liability insurance you don't.

Do you need a permit?

Almost never for cleaning. Roof cleaning is maintenance, not construction — no US municipality we've seen requires a permit for washing a roof. The exception-adjacent cases: some HOAs require approval before any exterior work (ask first, not after), and a few cities restrict chemical runoff into storm drains — a reputable contractor captures or diverts rinse water as standard practice. If the job uncovers damage that needs repair, that may need a permit depending on scope; check your municipality before any structural work begins.

Costly mistakes to avoid

• Hiring the pressure washer guy. The cheapest bid is usually the one that blasts your shingles at 3,000 PSI. Ask for the method in writing: soft wash or walk away.
• Cleaning a dying roof. $700 spent cleaning 25-year-old curling shingles is $700 not spent on replacement. Check the roof's age and condition first.
• Skipping the plant protection. Soft-wash solutions kill landscaping on contact. Any contractor who doesn't wet down and cover plants is cutting corners.
• Scraping moss dry. Dry scraping tears shingle granules off with the moss. Kill it with treatment first, let it release, then rinse.
• Ignoring the cause. Cleaning without addressing shade, debris, and drainage means you're buying the same job again in two years. Trim branches, clean gutters, consider zinc strips.
• DIY on a steep roof. No cost saving justifies a fall. Two stories or 6/12 pitch and up — hire it out.

Price the surface work in the pressure washing calculator, and read our per-square-foot pressure washing guide for the full method breakdown. While you're up there, the gutters usually need attention too — bundle the two and most contractors discount the second service.

Regional pricing and the seasonal calendar

Where you live changes both the price and the schedule. In the Pacific Northwest, moss is the dominant problem and cleaning is closer to routine maintenance than cosmetics — expect the biocide-treatment tier ($0.35–$0.70 per sq ft) as the default quote, and a 2–3 year cycle under tree cover. In Florida and the Gulf Coast, black-streak algae is the main target, competition among soft-wash companies is fierce, and straightforward jobs often land at the low end of the soft-wash range ($0.30–$0.45 per sq ft). In the Northeast, labor rates push the same job 15–25% above the national range, and the season effectively closes once overnight freezes arrive — a soft wash applied to a roof that freezes that night doesn't get its full dwell time. Desert Southwest roofs go longest between cleanings (dust and monsoon debris rather than growth), so per-visit prices matter more than frequency.

Timing saves real money everywhere. Spring is peak season — every homeowner looks up at the same time after winter — and good companies book out two to four weeks with no reason to discount. The same job quoted in late summer or fall often comes in 10–15% lower as schedules open up, and cleaning in fall has a practical edge: gutters and roof are cleared before winter storms instead of after. If your roof needs moss treatment, book it before the growth peaks in late spring — killing young moss takes one standard treatment, while a summer-mature colony is the two-visit job priced at the top of the range.