Roof Cleaning
Safe moss and algae removal that extends your roof’s lifespan by years — performed exclusively with gentle soft wash methods, never high pressure.
Your Roof Is Under Constant Biological Attack
Portland has earned its reputation as one of the most moss-prone cities in the country, and your roof absorbs the worst of it. Moss does not simply sit on top of shingles — it sends root-like structures called rhizoids beneath the edges, physically lifting and separating the material from the underlayment. Left unchecked, this creates pathways for water infiltration that lead to deck rot, attic mold, and structural damage that costs thousands to repair. Gloeocapsa magma — the cyanobacterium behind those dark streaks running down your roof — absorbs heat and accelerates shingle degradation from above. Regular professional roof cleaning addresses both threats, extending your roof’s functional life by five to ten years and keeping your warranty intact.
How We Protect Your Roof While Cleaning It
Every technique we use is designed to remove biological growth without compromising your roofing material.
Soft Wash Only — Never Pressure
Pressure washing a roof voids most manufacturer warranties and strips protective granules from asphalt shingles. We exclusively use low-pressure soft wash techniques approved by ARMA.
5-10 Year Life Extension
Removing moss and algae stops the two primary biological causes of premature roof failure. Clean roofs last significantly longer than neglected ones — a fact your insurance company understands well.
Energy Cost Reduction
Dark algae streaks absorb solar heat, forcing your attic temperature higher and your cooling system harder. Removing them restores your shingles’ intended reflectivity.
Manual Moss Removal When Needed
For thick moss buildup, we hand-remove the bulk before applying treatment. This prevents dead moss from clogging gutters and ensures the cleaning solution reaches the root layer.
All Roofing Materials
Asphalt shingles, cedar shake, concrete tile, metal panels, and flat membrane roofs each require different treatment concentrations. We adjust our approach for your specific material.
Zinc Strip Installation
After cleaning, we offer zinc strip installation along ridgelines. Rainwater carries trace zinc oxide down the roof surface, creating an environment hostile to moss and algae regrowth.
Our Roof Cleaning Process
Every step is designed to maximize cleaning effectiveness while minimizing any impact on your roofing material.
Roof & Gutter Inspection
We assess the roofing material, moss thickness, algae coverage, and overall condition. Any existing damage is documented and discussed with you before we begin treatment.
Heavy Moss Removal
Where moss has built up into thick mats, we carefully hand-remove the bulk material from the roof surface. This prevents gutter blockages and allows our treatment to reach the rhizoid layer directly.
Soft Wash Treatment
A biodegradable cleaning solution is applied at low pressure across the entire roof. The formula penetrates beneath shingles where moss rhizoids anchor, killing the growth structure completely.
Rinse & Prevention
After sufficient dwell time, the roof is gently rinsed. We discuss zinc strip installation for long-term prevention and schedule any recommended follow-up treatments.
The Hidden Cost of Ignoring Roof Moss in Portland
Most Portland homeowners know their roof has moss. Fewer understand what that moss is doing beneath the surface. Moss rhizoids — the root-like filaments that anchor the plant to your roof — work their way under the leading edge of each shingle. As the moss grows and absorbs rainwater, it swells, physically prying shingles upward and breaking the adhesive seal that keeps your roof watertight. During Portland’s heavy winter rains, water follows these lifted edges directly onto the underlayment and into the roof deck.
The financial consequences escalate quickly. A modest roof cleaning investment prevents deck rot that costs five to ten times more to repair. Insurance carriers operating in the Portland metro increasingly scrutinize roof condition during policy renewals, and some have denied claims where moss damage was clearly a pre-existing maintenance issue. Beyond structural risk, those dark Gloeocapsa magma streaks absorb solar radiation, raising attic temperatures and increasing your summer cooling costs. A clean roof is not just cosmetic — it is a financial decision with a measurable return.
Roofing Materials and the Right Cleaning Method
Each roofing material has specific vulnerabilities that dictate how it should be cleaned. Using the wrong method causes more damage than the moss itself. Here is how we handle the most common roof types across the greater Portland area:
- Asphalt shingles — soft wash only; pressure strips protective granules and voids the manufacturer warranty
- Cedar shake — gentle treatment with reduced solution concentration; we preserve the wood’s natural oils and patina
- Concrete and clay tile — soft wash with extended dwell time; tiles are durable but their porous surface traps deep-rooted growth
- Metal roofing — low-concentration rinse for cosmetic algae; metal resists biological damage but develops unsightly staining
- Flat membrane roofs (TPO, EPDM) — careful surface cleaning to remove ponding algae without compromising seam integrity
After the Clean: Preventing Moss From Coming Back
Cleaning your roof solves the immediate problem, but Portland’s climate guarantees that moss spores will land on your shingles again within months. The question is whether they take hold. Zinc strips installed along the ridgeline offer the most effective long-term defense. When rain hits the zinc, it carries microscopic amounts of zinc oxide down the roof surface, creating a chemical environment that inhibits moss, algae, and lichen establishment. Combined with regular gutter maintenance to prevent debris dams that trap moisture, and strategic tree trimming to increase sunlight exposure, zinc strips can extend the interval between professional cleanings to three or four years — even in Portland’s dampest neighborhoods.
Roof Cleaning FAQ
Straight answers to the questions Portland homeowners ask about roof maintenance.
Can I pressure wash my roof to remove moss?
No, and we strongly advise against it. Pressure washing strips the protective granule layer from asphalt shingles, voids most manufacturer warranties, and can crack or dislodge tile. Every major roofing manufacturer recommends low-pressure cleaning methods. We use soft wash techniques exclusively for this reason.
How does moss actually damage a roof?
Moss anchors itself with rhizoids that work beneath shingle edges, lifting them and breaking the adhesive seal. When it rains, water infiltrates under the lifted shingles and saturates the underlayment. Over time, this causes deck rot, mold growth in the attic, and eventually leaks into your living space.
Will roof cleaning void my shingle warranty?
Not when done correctly. In fact, most warranties require the homeowner to maintain the roof, which includes keeping it free of biological growth. Soft washing is the ARMA-recommended method. Pressure washing, on the other hand, explicitly voids most asphalt shingle warranties.
How often should I have my roof cleaned in Portland?
Most Portland roofs should be professionally cleaned every two to three years. Homes surrounded by mature trees, on north-facing slopes, or in heavily shaded neighborhoods like those in Lake Oswego and West Linn may need annual attention. Zinc strip installation can extend this interval significantly.
What are the dark streaks running down my roof?
Those streaks are caused by Gloeocapsa magma, a cyanobacterium that feeds on the limestone filler in asphalt shingles. It is not dirt and cannot be removed with water alone. Beyond being unsightly, the dark pigmentation absorbs heat and accelerates shingle aging. Our soft wash treatment eliminates it completely.
Do you install zinc strips for moss prevention?
Yes. We offer zinc strip installation as a standalone service or as an add-on after roof cleaning. Strips are mounted along the ridgeline so that rainwater carries trace zinc oxide across the roof surface, creating conditions that discourage moss and algae from establishing. It is the most cost-effective prevention method available.
Stop Moss Before It Costs You a New Roof
A professional roof cleaning today prevents expensive repairs tomorrow. Get a free assessment and find out exactly what your roof needs.
Serving Portland, Beaverton, Lake Oswego, Tigard, Tualatin, Hillsboro, Gresham, Milwaukie, Oregon City, West Linn, Happy Valley, Clackamas, Wilsonville, Sherwood, and surrounding communities throughout the greater Portland metro area.