That skylight you installed to flood your kitchen with natural light? After a Toronto winter, it's probably blocking 20-40% of the light it was designed to let in. Skylights face up — they collect everything that vertical windows shed. Pollen, bird droppings, mineral deposits from rain, snow melt residue, and construction dust all accumulate on glass that never self-cleans.
Why Skylights Get So Dirty
Faces Up
Catches everything that falls — pollen, droppings, dust, debris. Vertical windows shed most of this naturally.
Rain = Mineral Spots
Rain evaporates flat on skylights, leaving mineral deposits. Each rainfall adds another layer. 120+ TDS Toronto water.
Ice Dam Ring
Snow melts on warm skylight centre, refreezes at cold edges. Creates a permanent mineral/debris ring around the frame.
Low Pitch = No Shedding
Most skylights sit at 15-30°. Not steep enough to self-clean. Debris sits until manually removed.
Interior vs Exterior: Different Problems
Exterior skylight glass faces environmental contamination — the same contaminants as vertical windows, but concentrated 3-5x because of the upward orientation. Cleaning method: purified water + soft squeegee from roof surface. Never stand on or lean on a skylight — residential skylights are NOT designed to bear weight.
Interior skylight glass faces a different problem: condensation. Warm, humid indoor air rises to the highest point in the room — the skylight — and condenses on the cold glass surface. In Toronto's winter, this happens nightly. Over months, condensation leaves white mineral rings, mould at frame edges, and a cloudy film. Interior cleaning requires reaching the ceiling-mounted glass safely — typically extension poles or ladders, depending on ceiling height.
Skylight Condensation: When "Dirty" Is Actually Moisture
The #1 skylight complaint in Toronto: "My skylight looks foggy." In most cases, this isn't dirt — it's condensation. Three types:
- Interior surface condensation: Moisture on the room-facing surface. Normal in winter. Caused by high indoor humidity + cold glass. Solution: improve ventilation, reduce humidity, or upgrade to triple-pane. Cleaning removes the mineral residue left behind when condensation evaporates.
- Between-pane condensation: Moisture trapped between double-pane glass. This means the seal has failed. Cannot be cleaned — requires IGU (insulated glass unit) replacement. Cost: $200-$600 per skylight, depending on size and access.
- Exterior condensation: Morning dew on the outer surface. Normal and harmless — indicates the skylight insulation is working well (outer surface is cold enough to collect dew). Evaporates by mid-morning.
When to Clean Toronto Skylights
- April (essential): Remove winter's accumulation — salt film, ice dam mineral ring, debris trapped in snow. This is the most important skylight cleaning of the year. Entering peak sun season with dirty skylights means 3-4 months of reduced light.
- July (if near trees): Pollen and seed debris from spring, plus any bird droppings. Skylights under tree canopy need mid-summer cleaning.
- November (pre-winter): Remove fall leaves and pollen sludge before snow covers the skylight. Debris trapped under snow creates permanent staining and feeds mould growth at frame edges.
Add Skylights to Your Window Cleaning
$25-$75 per skylight when booked with window cleaning. ClearCoat™ purified water. Interior + exterior. Zero mineral spots.
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