We regularly get calls from homeowners convinced their roof needs replacing because of dark streaking, only for us to explain that in the vast majority of cases, they're looking at a cleaning problem, not a structural one. Here's how to tell the difference.
What Algae Streaking Actually Looks Like
Algae streaking (Gloeocapsa magma) typically appears as dark, somewhat streaky discoloration running down from the ridge or ventilation points, worst on north-facing roof sections that stay shaded and damp longest. It's usually uniform in texture — a coating on top of the shingle, not a change to the shingle itself.
Signs It's Actually Shingle Damage, Not Algae
Real shingle deterioration looks different: curling or cupped shingle edges, bald patches where granules have worn away entirely (exposing the black asphalt layer underneath), cracking, or shingles that are visibly missing. These are structural issues that cleaning won't fix — and in some cases, aggressive pressure washing can make granule loss worse, which is exactly why roofs need soft washing, not pressure washing, in the first place.
Age Is a Factor, But Not the Only One
Asphalt shingle roofs in Indianapolis typically last 20–30 years depending on material quality and installation. A 5-year-old roof with heavy streaking is almost certainly an algae problem — too young for meaningful wear. A 22-year-old roof with both streaking and granule loss might be nearing the end of its service life regardless of cleaning.
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Why This Confusion Costs Homeowners Money
We've talked to homeowners who got a full roof replacement quote from a roofing company before ever getting a second opinion on whether it was actually necessary. A soft washing costs a small fraction of a full roof replacement — see roof soft washing cost in Indianapolis for real numbers — and it's worth ruling out before committing to a much larger expense.
Getting an Honest Read on Your Roof
We'll tell you honestly if what we're looking at is algae (cleanable) or genuine wear that's beyond what cleaning can address — we don't have any incentive to talk you into a service that won't actually solve your problem, and if it looks like a roofing question rather than a cleaning one, we'll say so.
The Soft Washing Process Itself
For genuine algae streaking, soft washing uses a low-pressure, root-killing solution rather than the abrasive high pressure that would risk actual shingle damage. See pressure washing vs. soft washing for the full technical breakdown of why this matters.
Send Us a Photo
If you're not sure which category your roof falls into, send us a photo — we can often tell the difference remotely and give you an honest recommendation before you spend money on either service. We serve homes throughout Lawrence and the rest of the Indianapolis area.