Those black streaks running down an asphalt shingle roof aren't dirt — they're Gloeocapsa magma, an algae that's extremely common on Indianapolis roofs thanks to our humid summers. Roof soft washing removes it without the risk that comes with putting a pressure washer wand near shingles.
Typical Roof Soft Washing Prices
- Small/simple roof (under 1,800 sq ft, single story): $300–$400
- Mid-size roof (1,800–2,800 sq ft): $400–$550
- Large or steep-pitch roof: $550–$800+
Unlike a driveway, roof pricing isn't driven by square footage alone — pitch, height, and how many separate roof planes and valleys the crew has to navigate all factor in.
Why Pitch Matters More Than Size
A steep, walkable-but-tricky roof takes longer to treat safely than a larger but simpler low-pitch roof, because of the additional safety equipment, harnessing, and slower, more careful movement required. If your home has multiple rooflines, dormers, or a steep pitch typical of some newer Indianapolis subdivisions, expect your quote to reflect that complexity rather than just the total square footage.
Why It's "Soft Washing," Never Pressure Washing
Asphalt shingles have a granular surface layer that protects them from UV damage — high-pressure water can blast those granules loose, shortening the shingles' lifespan and potentially voiding a manufacturer's warranty. Soft washing uses a specialized, low-pressure application of a cleaning solution that kills the algae at the root, then rinses at low pressure. The algae and streaking lift away over the following day or two as the solution works, not from mechanical force. For the technical breakdown, see pressure washing vs. soft washing.
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How It Compares to Replacing Streaked Shingles
We get this question constantly: "Is my roof damaged, or just dirty?" In the vast majority of cases, black streaking is purely cosmetic algae growth sitting on otherwise healthy shingles — not a sign the roof needs replacing. Soft washing typically costs a fraction of what a new roof runs, and can restore curb appeal without touching the shingles themselves. We go deeper into how to tell the difference in roof soft washing vs. roof replacement.
How Often Indianapolis Roofs Need It
Most roofs in our service area benefit from soft washing every 2–3 years. Homes with heavy tree cover or north-facing roof sections that stay shaded and damp — common in older neighborhoods around Westfield and similar established areas — sometimes need it closer to every 18–24 months to stay ahead of regrowth.
Getting a Roof Quote
Roof pricing is one area where a quick photo genuinely helps us give you an accurate number without a site visit. Send us a picture of your roof and we'll walk you through pricing before anything is scheduled.