North Vancouver · Roof cleaning
Thick moss on a shaded Canyon Heights roof, and why we didn't pressure wash it
Under tall trees on the upper slopes of North Vancouver, north-facing roofs can turn green in a few seasons. The fix is gentler than most people expect.
November 6, 2026 · 2 min read · Spark Property Services
This story describes a typical situation we see in North Vancouver, not one specific customer.
The situation
A split-level home in Canyon Heights sits under a canopy of mature trees. The south side of the roof looks fine, but the north side is covered in thick cushions of moss, with green creeping up from the gutters toward the ridge.
The homeowner had been quoted for a pressure wash and wanted a second opinion before letting anyone point a high-pressure wand at a fifteen-year-old shingle roof.
Why we avoid pressure washing shingles
Asphalt shingles are protected by a layer of mineral granules. High-pressure water strips those granules along with the moss, which can shorten the roof's life and leave streaks that never fade. It also drives water up under shingle edges.
So on a roof like this, the moss comes off by hand with brushes and scrapers, working down the slope with the shingles rather than against them.
How we approach it
We start by walking the roof with fall protection and checking for lifted, cracked or missing shingles. Moss holds moisture, and on older roofs it sometimes hides damage that a roofer should look at.
Then the moss is removed by hand, section by section, focusing on valleys, the area behind the chimney and the lower edge where growth is heaviest. A low-pressure rinse clears what's left.
A moss treatment follows, as it does on every asphalt shingle roof we clean. It doesn't work overnight: remaining spores and stains fade over the following weeks and rains.
Because the debris ends up in the gutters, the gutters get cleaned at the same visit.
What to expect
A roof that sheds water properly again, cleared gutters, and an honest note about the roof's condition. On a shaded lot like this, moss will eventually return, but much more slowly once it's been fully removed and treated.
Questions we hear
Will the roof look brand new afterwards?
It will look clean, but some lichen staining can remain for a few weeks while the treatment works. Cleaning doesn't reverse wear or damage.
Should I trim the trees?
Reducing overhanging branches lets the roof dry faster and slows regrowth. An arborist can advise what's appropriate for your trees.
