Skylight Installation and Replacement for Ontario Homes
Skylights are one of the most effective ways to bring natural light deep into GTA homes. Done right, they add beauty and value. Done wrong, they’re the number one source of water intrusion. Here is what you need to know in 2026.
Skylight Types
| Type | Notes | Cost (installed) |
|---|---|---|
| Fixed (non-opening) | Light only, no ventilation | $1,500-3,500 |
| Vented (manual or electric) | Light + ventilation | $2,500-5,500 |
| Tubular (sun tube) | Small spaces, low disruption | $800-1,800 |
| Roof window | Attic conversions, can clean inside | $2,000-4,500 |
Ontario Building Code Requirements
- Minimum double-pane (thermopane) glazing
- Tempered or laminated safety glass
- Energy Star Climate Zone 6 rating strongly recommended
- Building permit required for new structural openings
Why Skylights Leak (and How to Prevent It)
90% of skylight leaks are flashing failures, not glazing defects.
Proper installation requires:
- Integrated flashing kit (manufacturer-supplied — never dry-mount)
- 6-inch step flashing at sides
- Saddle flashing at upslope end
- Weep holes at head
- Never substitute roofing cement for proper flashing
Energy Performance in GTA Climate
Skylights lose heat in winter. Minimize losses with:
- Triple-pane glazing (R-6 to R-9 centre of glass)
- Low-e coating
- Insulated shaft (minimum R-20)
- Motorized blackout blinds for nighttime insulation
Condensation on Skylight Shafts
Dripping from a skylight interior in winter = shaft insulation problem, not a glazing leak. Insulate shaft to R-20 minimum, install vapour barrier on warm side, and air-seal at ceiling level.
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LF Builders installs and replaces skylights across the GTA. lfbuilders.ca