Roof Cleaning in Harrison Township
The black streaks on a Harrison Township roof are a living algae colony, and lake air feeds it. North slopes over the canals stay damp past noon, shingles under the river-street canopy grow moss on top of the streaks, and a roof treatment kills all of it without a pressure washer ever touching the shingles.
The dark streaks that run down asphalt shingles are a blue-green algae that feeds on the limestone filler in the shingle and spreads wherever the roof stays wet longest. On a canal home that is the slope facing the water, where morning fog sits until the sun clears the houses across the canal, and on the inland ranches west of Jefferson Ave it is the north slope under a sixty-year maple. The river streets near the mouth of the Clinton River get both, plus moss, because the Lake St. Clair Metropark nature area and the bottomlands keep the shingles shaded through the afternoon. Only the open lake lots around Lakeside, with wind on them, stay ahead of it.
A roof treatment kills the colony where it lives. The solution goes on at low pressure, no stronger than rain, and sits while it kills the algae, the moss and the lichen down to the root; the streaks fade over the following weeks as rain carries off the dead growth. No pressure washer ever touches the shingles; forced water scrubs off the granules that keep sun off the asphalt and takes years off the roof. Done this way, a treatment holds three to five years, shorter on a canal-facing slope that never fully dries and longer on a lake lot with sun and wind.
Roof treatment starts at $450, and the price follows the roof's square footage and pitch rather than the address. It pairs naturally with a gutter cleaning, since the debris in the trough and the streak above it are the same moisture problem, and with a house wash, because the crew is already staged with the equipment for second-story work. The drive from our Clinton Township shop is about 15 minutes. If your roof is cedar shake rather than asphalt, the chemistry changes; our note on moss on cedar shake explains how.
Treated From the Ladder, Not Walked
We look at the roof from the ground and the ladder first, note the slopes that hold the streaks, check for lifted shingles and soft decking, and cover or bypass anything below that should stay dry: the deck, the dock, the boat under its cover, the plantings along the seawall. Gutters are plugged or diverted so the solution does not run to the lawn or the canal. The treatment is applied at low pressure from the ladder or the roof edge, working the streaked slopes heaviest, and it dwells until the growth is dead. Moss loosens and sheds over the following weeks rather than being scraped. Downspouts are flushed at the end, and photos of each slope go on the report.
Granules in the Gutter
The costliest mistake on a Harrison Township roof is pressure washing it. A pressure wand strips the ceramic granules that shield the asphalt from ultraviolet, and you find them in the gutter and at the downspout the next day; the shingles then age in a few summers what should have taken a decade, and on a lake lot that already takes reflected sun the loss shows fast. Scraping moss by hand does the same damage in strips. The other error is a treatment mixed too weak to reach the root, which fades the streaks for a season and lets them return by the next spring.
Timing It Right
Roof treatments run from April into November, any day above freezing with no rain expected for a few hours. The canal streets book heaviest in spring before the boats go in and the docks fill with gear, and again in September when the streaks are at their darkest after a humid summer. Pairing the treatment with the fall gutter cleaning puts both on one trip. Our guide on what the black streaks are answers the questions we hear most on the phone.
Price Roof Cleaning for Your Harrison Township Home
Pick your property size and condition for a real range in about twenty seconds — bundle other services to watch the visit price drop.
1 · What do you need cleaned?
2 · Home size
3 · Condition
Roof Cleaning in Harrison Township: FAQs
Will the roof treatment run into the canal?
No. Before the solution goes on, gutters are diverted or plugged and the seawall plantings are wet down, so the runoff is captured at the downspouts or held on the lawn side. Rinse water never goes over the seawall edge. The chemistry sits at the biodegradable end of the range and is used at the dilution the roof needs, not stronger.
How long does a roof treatment last near the lake?
Three to five years. The canal-facing slope, which stays damp longest, sits at the three-year end, and a lake lot with wind and sun reaches five. The growth is killed to the root rather than rinsed off, so the streaks start over from nothing instead of from what was left behind.
How much does roof cleaning cost in Harrison Township?
From $450 for a typical ranch, with two-story canal homes and steeper pitches priced by square footage and access. The number is the same on the canal as on an inland street. Putting the gutters on the same visit is cheaper than a second trip, and the written quote shows each on its own line.
Do the streaks come back faster on the river streets?
Yes, because those roofs sit in shade from the Metropark nature area and the river bottomlands and stay damp through the afternoon. They also grow moss, which holds water against the shingles and lifts the edges. A treatment every three years there, rather than five, and trimming limbs that overhang the slope keep the roof ahead of it.
More in Harrison Township
Deeper reading: What Are Those Black Streaks on My Roof? (And Why You Shouldn't Ignore Them) and The Best Time of Year to Power Wash a House in Michigan.
Book Roof Cleaning in Harrison Township
Request a free, no-pressure estimate today. Most quotes are delivered within 24 hours, and every job is backed by our satisfaction guarantee.
Get My Free Estimate or call (586) 284-3810 — Mon–Sat, 8am–10pm