Home › Recent Projects › Roof Cleaning in Woodinville, WA (Needle-Packed Valleys, Zinc Sulphate)
Squatch Roofing cleaned a two-story roof in Woodinville, WA 98072 on July 8 and 9, 2026, with zinc sulphate powder spread across the shingle slopes. The June 8 inspection found fir needles caught along the shingle courses, and on the first work day the overhead photos show the roof’s valleys packed with needles and debris. By the time the powder went down, the valleys were clear. The job is priced per square foot of roof.
| Location | Woodinville, WA 98072 |
|---|---|
| Service | Roof cleaning with zinc sulphate powder |
| Property | Two-story home with a multi-level asphalt shingle roof, several valleys, and tall conifers around the lot |
| Inspection | June 8, 2026: attic, roof surface, gutters, and every side of the house; 38 photos on file |
| Findings | Fir needles along the shingle courses and keyways; needles and debris built up in the valleys |
| Treatment | Zinc sulphate powder, priced per square foot of roof (square footage not recorded in the job file) |
| Schedule | Inspection June 8; cleaning July 8 to 9, 2026 |
| Project investment range | $1,800 to $2,800 |
What Squatch Found on the Inspection
The 21-point inspection ran June 8, 2026. The inspector started in the attic and then walked the roof and the outside of the house.
- Attic: OSB sheathing on the trusses, blown insulation across the ceiling, and a duct running up through the insulation, photographed bay by bay with a flashlight.
- Shingle surface: fir needles lodged along the shingle courses and in the keyways across the slopes.
- Lower roofs: needles scattered across a lower roof section above a gutter.
- Gutters: needles along the gutter at a lower eave.
What We Recommended
The job is a single line item: roof cleaning with zinc sulphate powder, priced per square foot of roof. There is no repair, tune-up, or gutter cleaning on the invoice. The job file does not record the roof’s square footage.
How the Cleaning Went
July 8: the day started with overhead photos of the roof. Several valleys were filled with a mat of needles and debris, with more needles on the slopes and in the shingle courses. In the next set of photos the valleys are clear, and the zinc sulphate is spread across the slopes. The powder shows as white streaks and drifts on the shingles. It is left dry on the roof for rain to carry it down the slopes.
July 9: the crew came back with a ladder and finished the remaining slopes, including lower roof sections at the edges of the house. The photos show powder across the upper slopes, around the roof vents, and along the lower roof edges.
The Finished Roof
Every slope in the July 8 and 9 photos carries a coat of zinc sulphate, and the valleys that were packed with needles on the first morning are clear. The white color is the powder itself, not damage to the shingles. There are no later photos in the file showing the roof after rain.
What This Roof Cleaning Cost
Project investment range: $1,800 to $2,800. This range reflects the scope of this completed project and is not a current quote. It is anchored on the final invoice total, which includes Washington sales tax.
Zinc sulphate is priced by the square foot of roof, so the size of this two-story, multi-level roof set the price. It took two days on site to cover every slope.
What Homeowners With Similar Roofs Should Know
Look at the valleys. On this roof the heaviest buildup was in the valleys, not on the open slopes. The overhead photos showed it before the powder went down.
The white is supposed to be there. Right after a zinc sulphate treatment the roof looks dusted. That is dry powder waiting for rain.
Related questions
How much did this roof cleaning in Woodinville cost?
The project investment range was $1,800 to $2,800 for a zinc sulphate cleaning of a two-story, multi-level roof over two days. The range reflects this project’s scope and is not a current quote.
What did the inspection find?
On June 8, 2026, the inspector found fir needles caught along the shingle courses and keyways, needles on a lower roof, and needles in a gutter. On the first work day, the overhead photos showed the valleys packed with needles and debris.
Why is the roof white after the treatment?
The white streaks are the zinc sulphate powder. It is spread dry and left on the shingles for rain to wash it down the slopes.
How long did the roof cleaning take?
Two days on site, July 8 and 9, 2026. The inspection was a month earlier, on June 8.
Were the gutters cleaned too?
No. Gutter cleaning is not on this job’s invoice. The only line item is the zinc sulphate roof cleaning.
Needles piling up on your roof?
If needles are collecting in your valleys or along your shingle courses, Squatch Roofing can run a free 21-point inspection, show you the photos, and recommend the right roof cleaning. Squatch serves Woodinville, the Eastside, and the greater Seattle area. Related projects: the Kirkland zinc sulphate cleaning with needles behind a chimney chase and the Redmond zinc sulphate cleaning for moss in the course lines. Schedule an inspection or call (425) 292-8327.
This project documentation was prepared by Squatch Roofing from the job records and photos from our crew, October 2026. Technical review by Ben Metsker, Manager, Squatch Roofing.
