Roof Cleaning in Severn.

Why Severn roofs grow things

Two conditions decide whether a roof grows moss, and Severn has both. Shade, from the mature pine and mixed bush that covers most of the township, so the shingles never fully dry. And organic litter — needles, seeds, and leaf fall collecting in the valleys and along the north slope, holding moisture against the roof like a wet sponge.

That’s a different problem than the one most Simcoe County towns have. On an open lot in town you mostly see black streaking — gloeocapsa algae, feeding on the limestone filler in the shingles, running down the roof in dark curtains. In Severn you get the streaking and the moss: green cushions in the valleys and along the shaded slope, lifting shingle edges as they thicken.

The moss is the one that actually costs you. It holds water against the shingle, works its way under the edges, and in a freeze-thaw winter — which is every winter here — that water expands and lifts. Left alone long enough it stops being a cleaning job.

Severn tip: if only the north or tree-side slope is green, that’s normal and it’s exactly the pattern we expect. It doesn’t mean the roof is failing — it means that side never gets the sun to dry out.

How we clean roofs in Severn

No pressure, ever. A pressure washer strips the protective granules off along with the algae, shortens the roof’s life, and voids most shingle warranties. We use a low-pressure soft wash that kills the algae and moss at the root — the method roofing manufacturers actually recommend.

One honest expectation, and it matters more in Severn than anywhere because the moss here is thick: the black streaks clear fast, the moss does not vanish the day we leave. Killed at the root, it dries out and sheds on its own over the following weeks with wind and rain. That’s slower than scraping — and it’s what keeps your shingles whole.

Metal and steel roofs, common on the cottages and outbuildings out this way, get the same low-pressure treatment.

Where we work in Severn Township

Washago, Cumberland Beach, Severn Bridge, Marchmont, West Shore, Port Severn, Fesserton, Uhthoff, and the shore roads along Couchiching, Sparrow Lake, and the Severn River — plus Orillia, Coldwater, and Oro-Medonte next door.

Roof work pairs naturally with eaves clearing, since the debris comes off the roof anyway. See how soft washing works or the guide for cottage owners.

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