Roof Cleaning That Kills Black Streaks for Good

There is no single flat rate for roof cleaning, and any company quoting one over the phone without looking at your roof is guessing. Price comes down to four things: the square footage of roof surface (not floor plan), the pitch, how many stories and access points the crew has to work around, and how heavy the algae, moss, or lichen growth is.

A steep, three-story roof with heavy moss on the north slopes takes far more solution and setup time than a single-story ranch with light streaking, so the two should never cost the same. We measure and price most Capital Region roofs remotely with satellite imagery, then give you one firm, flat number in writing — usually within a business day. That price is the price: no on-site upsells, no change orders once the truck is in the driveway.

Two things that lower your cost: bundling. Most homeowners have us wash the roof and the house siding on the same visit, which saves a full mobilization, and active or retired military, first responders, and seniors receive a discount. Ask when you request your quote.

The dark stains running down your shingles are not dirt, soot, or normal aging. They are a living blue-green algae called Gloeocapsa magma. It feeds on the limestone filler used in modern asphalt shingles, and it thrives in exactly the conditions the Capital Region delivers every summer — humidity off the Hudson and Mohawk, warm nights, and shaded, north-facing slopes that stay damp.

It spreads by airborne spores, which is why once one house on the street streaks, the neighbors usually follow within a couple of seasons. Left alone, the algae mat holds moisture against the shingle surface, accelerates granule loss, and gives moss and lichen a foothold. That granule loss is the part that actually costs money: it is the leading cause of shingles failing years before their rated life.

Bleaching the streaks off the surface does nothing about the organism underneath. A proper soft wash kills it at the root, which is why our results hold for years rather than a season — backed by a 2-year no-streak guarantee.

Soft washing means the cleaning is done chemically, not mechanically. Instead of forcing water at the shingle, we apply a professionally diluted, ARMA-approved solution at roughly garden-hose pressure, let it dwell long enough to kill the algae, moss, and lichen at the root, then rinse gently. The shingle surface is never scoured and the protective granules stay exactly where the manufacturer put them.

This is the method shingle manufacturers and the Asphalt Roofing Manufacturers Association call for, and it is the reason a soft wash keeps your warranty intact while a pressure wash typically voids it. Most of the work is done from ladders and the ground; we only step onto a roof when there is no other way to reach an area, and always with fall protection.

Before any solution goes on the roof we soak the plants, lawn, and landscaping with fresh water and cover anything sensitive, then re-soak everything during and after the rinse. Gutters and downspouts get flushed before we leave.

Moss is a different problem from streaking. Where algae stains the surface, moss builds a thick mat that lifts shingle edges, holds water against the deck, and in our freeze-thaw winters that trapped water expands and pries the shingle apart. Lichen is worse still — it roots into the shingle mat itself.

Both are treated with the same low-pressure soft wash, but the timeline is different and we will tell you that up front. Moss and lichen die during treatment, then release and weather away over the following weeks of rain rather than vanishing the day we leave. Scraping or blasting them off may look faster, but it takes the granules with it.

If your roof sits under mature tree cover — common in Loudonville, Niskayuna, Delmar, and the older Saratoga Springs neighborhoods — plan on a wash roughly every three to five years to keep growth from re-establishing.