Roof Cleaning in Schaumburg: Soft Wash vs. Pressure Washing
Every October a few Schaumburg homeowners rent a pressure washer for the driveway, look up at the black streaks on the north slope, and think they will do the roof while they have it. Please do not. A pressure washer takes the granules off an asphalt shingle the way a sandblaster takes paint off a car, and a roof that was cosmetically ugly with ten years left becomes a roof that is bald and brittle with three. Here is what actually cleans a roof, what it costs, and when the honest answer is to leave it dirty.
What pressure does to a shingle
An asphalt shingle is a fiberglass mat, a layer of asphalt, and a coating of ceramic granules that protect the asphalt from UV. The granules are pressed in when the shingle is hot at the factory. On a 15-year-old roof that has been through 15 Illinois winters, they are already loosening. A pressure washer at 2,000 psi — the low end of a rental — strips them by the handful. You see the runoff turn black and sandy and think you are cleaning the roof. You are removing it.
Pressure also drives water up under the tabs and under the flashing, especially on the low-slope sections of split-levels, and it will find every seam in the ice-and-water shield. And the manufacturer's warranty specifically excludes damage from pressure washing.
The same goes for a stiff brush, a metal scraper, and the "walk the roof with a garden hose on jet" approach. If it involves force, it costs granules.
What a soft wash is
A soft wash is a cleaning solution applied at garden-hose pressure — under 100 psi — left to sit, and rinsed. The solution does the work, not the water. For the black algae streaks that cover the north slopes of half the roofs in the northwest suburbs, the solution is a diluted sodium hypochlorite mix with a surfactant, applied from the ridge down, allowed to dwell for 15–20 minutes, and rinsed gently. The streaks fade over the following days and weeks as the dead algae washes off in rain. For moss, the same solution kills it; the dead moss is left to dry and blows off or is brushed loose by hand a few weeks later.
A competent soft-wash crew wets down and covers the landscaping, runs the downspouts into a bucket or out to the street, and rinses everything below the roof afterward. The runoff kills plants if it is left on them.
What it costs
| Job | Typical Schaumburg price |
|---|---|
| Soft wash, single-story ranch | $300 – $550 |
| Soft wash, two-story or steep | $450 – $800 |
| Moss treatment and hand removal | $400 – $900 |
| Zinc or copper strip at the ridge, installed | $150 – $400 |
| Gutter cleaning with the wash | $120 – $250 |
Priced by the house and the pitch. Anyone quoting by the hour, or quoting a pressure wash, is not who you want on the roof.
When to bother
Yes, if the roof is under about 15 years old, the shingles are still flexible, and you want the streaks gone for a sale or because you look at them every day. A soft wash on a 10-year-old architectural roof does no harm and lasts 3–5 years.
Maybe, if the roof has moss along the north eave. Moss holds water against the shingle and under the tab edges, and over a few winters it lifts the tabs and the freeze-thaw does the rest. Killing it is worth doing even on an older roof, as long as it is done gently.
No, if the roof is over 18–20 years old and the streaks come with granule loss, curling or cracked tabs. The cleaning will not hurt it much, but you are paying $500 to make a roof that needs replacing look slightly better. Put the money toward the replacement, and if it is being sold, disclose the roof age and let the price reflect it. The signs a roof is at the end post has the checklist.
Doing it yourself
It can be done from a ladder on a single-story ranch with a pump sprayer and a garden hose, on a cool overcast day, with the plants covered and the gutters running to a bucket. The risks are the ladder, the bleach on the lawn, and walking on a wet roof. Two-story roofs and anything over a 6:12 pitch are not a homeowner job. If you do it yourself, use a product labeled for roofs, not straight pool chlorine, and do not walk on the treated area.
The other half: keeping it clean
A soft wash treats the symptom. The algae come back in three to five years unless something changes. The moss and algae post covers prevention — algae-resistant shingles on the next roof, a zinc or copper strip at the ridge, and cutting back the silver maple that shades the north slope. On most Schaumburg houses, the streaks are on the slope facing the neighbor's house and nobody but the neighbor sees them; the roof does not care. Spend the money where the roof does care, which is the flashing, the boots and the eaves.
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