Those ugly black streaks running down your roof are not dirt — they are algae, and left alone they shorten the life of your shingles. If you are searching for roof cleaning in Macomb County, this guide explains how to remove those streaks safely, what it costs, and the one mistake that voids many shingle warranties.
What causes black streaks on Michigan roofs?
The dark streaks on north- and shade-facing roof slopes are a blue-green algae called Gloeocapsa magma. Southeast Michigan's humid summers and heavy tree canopy — from Macomb Township to Shelby Township and Clinton Township — create the perfect conditions for it to spread. Beyond looking bad, the algae feeds on the limestone filler in asphalt shingles, degrading them over time and driving up cooling costs as the darkened roof absorbs more heat.
Never pressure wash a roof
This is the most important thing to know: high pressure will destroy your roof. Blasting shingles strips away the protective granules, forces water under the shingles, and will almost certainly void your manufacturer warranty.
The correct method is soft washing — the same approach recommended by shingle manufacturers and the ARMA (Asphalt Roofing Manufacturers Association). Our roof cleaning service uses low pressure and specialized, plant-safe cleaning solutions that kill the algae, moss, and lichen at the root without touching a single granule.
What roof cleaning costs in Macomb County
Soft-wash roof cleaning in our area typically runs $300 to $600+, depending on:
- Roof size, pitch, and number of stories
- Severity of algae, moss, or lichen growth
- Accessibility and surrounding landscaping
Many homeowners bundle roof cleaning with a house wash and gutter cleaning for a complete top-to-bottom exterior refresh — and save on a single visit.
How long does it last?
A proper soft wash removes the algae rather than just rinsing the surface, so results last far longer than a pressure rinse — typically several years. Homes surrounded by trees or near water may see regrowth sooner and benefit from periodic maintenance.
Signs it is time to clean your roof
- Dark streaks or patches, especially on north-facing slopes
- Green moss or crusty lichen at shingle edges
- Debris and organic buildup in valleys
- A roof that simply looks older than it is
Catching it early protects your shingles and delays an expensive roof replacement.
Restore your roof the safe way
Expert Power Washing is licensed, fully insured, and based right in Macomb Township, serving all of Macomb County and Southeast Michigan with safe, manufacturer-approved soft washing.
Call or text (586) 372-8051, or request a free roof cleaning quote. We will assess your roof and give you honest, no-pressure pricing.
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About the author
Patrick Kishek
Patrick runs the crews at Expert Power Washing and is on the truck for most jobs — soft-washing siding, cleaning roofs, restoring decks and driveways across Macomb County. The advice here comes from what actually works on Michigan homes, season after season.
Meet the Expert Power Washing team →