Skylights near you

The right type depends on the room below, how much light and fresh air you want, and how much space separates the roof from the ceiling.

Installing a skylight means cutting through the roof covering and the deck, working around or reframing rafters or trusses, and building a light shaft down to the ceiling. Outside, most leaks come down to the flashing: the metal pieces and membrane that steer water around the unit and back onto the roof. Manufacturers make flashing kits matched to their units and to different roof coverings, and installers work from those instructions and from CSA A440.4, the Canadian installation standard that covers skylights as well as windows and doors.

This is roof work at height, a job for a roofer or an experienced skylight installer rather than a homeowner on a ladder. Adding or replacing a skylight while the roof is being redone lets the flashing and new roofing go in together; see the roof replacement page for that project.

Water dripping from a skylight in January is often condensation rather than a leak. Natural Resources Canada explains that condensation forms in cold weather when moist indoor air touches cooler surfaces, and that the risk rises as it gets colder outside or more humid inside. Warm, humid air collects near the ceiling, where the skylight is usually the coldest surface. NRCan also notes that condensation can form on the walls around a skylight, and between the panes when the seal of the glazing has failed.

Timing is the best clue: condensation shows up on cold, clear days, on the glass or the shaft walls, while a leak tends to appear during rain or a thaw and runs from the frame or the ceiling around it.

Because it faces the sky, a skylight tends to lose more heat on winter nights and take in more sun on summer afternoons than a wall window of similar size. Placement matters: a unit on a shaded or north-facing slope gives softer, steadier light with less summer heat, while one facing the afternoon sun may need a shade or tinted glazing. NRCan lists low-emissivity coatings, gas fills, insulated frames and triple glazing among the features that improve windows, doors and skylights, and advises hiring a trained installer so the product performs as it should.

NRCan also sets the ENERGY STAR criteria for these products in Canada. Version 5.0 of its technical specification, which took effect on January 1, 2020, caps the U-factor of a certified skylight at 2.29 W/m²·K, and unlike windows, skylights have no Energy Rating path. Look for the label, or ask the installer for the certified rating of the model proposed.

When the unit itself is in good shape, a leak can often be fixed by redoing the flashing, resealing the curb or replacing damaged shingles and underlayment around it. Ice dams that form just below a skylight can also push meltwater under the flashing, which points as much to heat escaping into the attic as to the skylight.

Replacement makes more sense when the glazing is fogged between the panes, the frame is cracked or rotted, a plastic dome has turned brittle and yellow, or the flashing was improvised on an old unit. When the roof around a skylight is being redone, replacing the skylight at the same time avoids tying new roofing into worn flashing. On some models, a fogged sealed unit can be replaced on its own; ask whether yours allows it.

Swapping a skylight in the same opening is usually treated as maintenance, but cutting a new opening changes the roof structure, and many municipalities want a permit for that, especially when rafters or trusses are cut or the house sits in a heritage area. Rules differ from one city to the next, so check with yours before the work is scheduled, and have the contract say who applies for the permit.

Roof trusses are engineered as a system and shouldn't be cut without a design from an engineer or the truss manufacturer. In Quebec, the contractor must hold an RBQ licence with the subclasses that match the work, which you can confirm in the RBQ's online registry.