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Service · 01

Roof Cleaning, at the root

Moss, lichen and black streaks lifted at the root — done to ARMA and shingle-maker guidelines.

What it is

Roof Cleaning — done properly

A roof soft wash tuned for the Pacific Northwest and done to ARMA (Asphalt Roofing Manufacturers Association) and shingle-manufacturer cleaning guidelines. We apply our in-house roof treatment to dissolve moss, lichen and Gloeocapsa (the black streaking) at the root, let it dwell, then rinse the whole roof clean. You have two options: our recommended premium soft wash — low pressure, granule-safe — and a lower-cost budget powder treatment. On the premium wash, zero high pressure means zero granule loss and no voided shingle warranty.

The same roof after an Olson Pro Wash soft wash
Mossy, streaked roof before soft washing
Before After
Roof soft wash — before / after
Why it matters here

What roof cleaning is up against in the Northwest

Marine humidity

Persistent damp off Puget Sound keeps north-facing slopes wet for weeks at a time, so moss spores never really stop working.

Evergreen canopy

Fir, cedar and big-leaf maple drop needles and shade onto the roof — the exact conditions moss and lichen need to take hold.

By the guidelines

ARMA and the shingle manufacturers call for low-pressure chemical cleaning, not pressure washing. Our recommended soft wash follows that, so the granules and the warranty stay intact.

What's included

Every job, every time

  • Kills moss, lichen and black streaking at the root
  • Done to ARMA and shingle-manufacturer cleaning guidelines
  • Premium soft wash (recommended) or a budget powder treatment
  • Roof rinsed clean after our in-house treatment dwells
  • Gutter guards, skylights and landscaping protected
How it works

Four steps, no surprises

01

Inspect & protect

We look over the roof, note the problem slopes and flashing, then pre-wet and tarp landscaping, gutter guards and downspout outlets.

02

Apply our roof treatment

Our in-house roof treatment is applied at low pressure across the whole roof, dissolving moss, lichen and black algae at the root.

03

Let it dwell

The treatment is left to work down into the growth; heavy lichen gets a second pass.

04

Rinse & clear

The whole roof is rinsed clean without disturbing the granules, and debris is flushed out of the gutters. Loosened growth keeps dropping over the following weeks.

What it costs

The premium soft wash is our recommended option; the budget powder treatment is quoted lower. Priced by roof size, pitch, access and how much growth is present — most single-family roofs land between $299 and $1,200, quoted firm after we see photos or the roof itself.

Want it kept up automatically? Put it on a maintenance plan for a lower per-visit rate.

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Roof Cleaning FAQ

Before you book

Soft wash or powder treatment — which do you recommend?

The premium low-pressure soft wash, every time. It is the method ARMA and the shingle manufacturers call for, and it protects the granules and your warranty. We also offer a lower-cost budget powder treatment — we walk you through the trade-offs before you choose.

How long until the moss actually disappears?

Loose moss rinses off during the visit; the rest browns and drops over the following weeks as rain and wind clear it. Heavy lichen can take a full season to fully release.

How often does a Snohomish County roof need this?

Most homes here go 2–4 years between washes. Roofs under heavy fir shade or on the north side of a hill are closer to every 2 years. Keeping the gutters clear helps.

Ready for roof cleaning that actually lasts?

Free, itemized quotes across 18+ cities in Snohomish & King County. Most estimates back the same day.