In the video above, you can see the complete roof soft washing process on a three-story Greenwood home. This is exactly how I approach roof soft wash jobs throughout this neighborhood — methodical plant protection, proper safety setup, and precise sodium hypochlorite application that eliminates moss without the damage that pressure washing causes.
Why Greenwood Roofs Need Soft Washing Treatment
Greenwood’s tree-lined streets create the perfect storm for roof moss growth. The canopy cover keeps roofs damp longer after rain, and the organic debris from maples and evergreens feeds moss colonies year-round. I’ve been cleaning roofs in Greenwood since 2014, and the moss density here consistently ranks among the heaviest I see across Seattle.
Soft washing roof surfaces with sodium hypochlorite kills moss at the cellular level without the mechanical damage that pressure washing causes. The chemical solution penetrates moss root systems, eliminating the organic growth completely. On composite and asphalt shingles, this is the only safe method — pressure washing blasts granules off shingles and voids manufacturer coverage.
My Roof Soft Washing Process in Greenwood
Every roof cleaning starts with comprehensive plant protection. I pre-soak all vegetation around the home with water, which dilutes any chemical overspray that might occur during application. Greenwood properties often have established landscaping close to the roofline, so this step is critical.
Before any chemical application, I blow all debris from the roof and gutters using a leaf blower. This includes needles, leaves, and loose moss. I also assess downspout discharge points — if gutters drain directly onto garden beds, I bag the downspouts to catch runoff.
The actual soft washing uses my 12V rig with a proportioner system that delivers precise sodium hypochlorite and surfactant concentration every time. Never batch-mixed solutions that can vary in strength. I apply the treatment working from bottom to top, always spraying toward the roof at edges to control chemical placement.
On composite and asphalt roofs, the treatment requires no rinse. The active ingredients continue working for weeks, and moss dies naturally. Dead moss washes off gradually with rainfall over the next 3-6 months. This is normal — the roof doesn’t look completely clean on the same day, but the treatment is eliminating the organic growth.
Safety and Equipment for Multi-Story Homes
Many Greenwood homes are two or three stories with steep pitches. Safety equipment is non-negotiable on these jobs. I use a full harness system when roof access requires it, and often need to ladder up multiple times to reach different roof sections safely.
On the three-story job shown in the video, I used a 28-foot ladder to reach the front section, then brought up a 20-foot ladder to access the upper roof areas. This setup takes extra time but eliminates fall risk. The degree of difficulty is higher on complex rooflines, but the soft washing method itself remains the same.
Licensed WA L&I #WORLDGW748D6, I carry full insurance and bonding for this type of work. Roof cleaning involves chemical handling and height access — proper licensing and coverage protect both the homeowner and the contractor.
Maintenance Schedule and Long-Term Results
I recommend soft washing roof treatment every three years for composite and asphalt shingles in the Pacific Northwest. Our climate accelerates moss regrowth, especially in neighborhoods like Greenwood with heavy tree cover. Annual zinc treatment can extend this timeline by inhibiting new moss formation.
The sodium hypochlorite treatment eliminates current moss growth, but it’s not permanent moss eradication. New spores will eventually colonize the roof again. Regular treatment keeps moss from establishing the thick colonies that become visible from the street and start causing shingle damage.
Gutter cleaning pairs naturally with roof soft washing since debris loosened during the chemical process can clog gutters. I often recommend scheduling both services together to address the complete roof system.