Skylights in Calgary homes: light, and a hole in your roof
A skylight is worth it in Calgary when it is installed and flashed properly, because it brings daylight deep into a home through long winters that are cold but often bright.
Calgary gets plenty of sun even in January, and a well-placed skylight can turn a dark hallway, stairwell or kitchen into the brightest room in the house. The trade-off is simple: every skylight is an opening cut through the roof deck, and that opening has to survive hail, drifting snow, ice dams and dozens of freeze-thaw cycles a year. Whether a skylight becomes a favourite feature or a recurring stain on the ceiling comes down to what happens on the roof side.
We are a roofing company, so our work is that roof side: installing, replacing and re-flashing skylights and sun tunnels, and fixing skylight leaks. Interior drywall finishing, painting, electrical work for powered or venting units and larger light-shaft framing may involve other trades, and we will tell you plainly where those come in.
Types of skylights
Most Calgary homes use one of three skylight styles, mounted in one of two ways, with a choice of glazing.
Fixed skylights
Fixed skylights do not open. They are the simplest unit, with the fewest moving parts and seals to wear out, and they suit rooms where you want light rather than airflow.
Venting skylights: manual or powered
Venting skylights open to release heat and moisture, which helps in kitchens and bathrooms. Manual units use a crank or pole; powered units use a motor and often a rain sensor. Powered units need wiring, which is electrical work handled by a qualified electrician rather than a roofer.
Tubular skylights and sun tunnels
A sun tunnel uses a small dome on the roof and a reflective tube that carries light down through the attic to a diffuser in the ceiling. It gives soft, even light without a full light shaft.
Curb-mounted vs deck-mounted
A curb-mounted skylight sits on a raised wooden frame built above the roof deck, and the flashing wraps the curb. A deck-mounted skylight fastens directly to the deck with an integrated flange and flashing kit, giving a lower profile. Both work on Calgary roofs when the flashing is done correctly; the raised curb can help keep water and slush away from the unit.
Glazing options
Low-e coatings reduce heat loss in winter and heat gain in summer. Laminated glass holds together if it cracks, and tempered or laminated glazing stands up to hail far better than older plastic domes. For a hail-belt city, tougher glazing is a sensible choice.
Why skylights leak
Skylights leak mostly because of flashing, not glass. The common causes we see on Calgary roofs:
- Failed or improvised flashing. Units sealed with a bead of caulk or roofing cement instead of step flashing and a proper kit.
- Old caulk-sealed installs. Sealant hardens and cracks after years of sun, cold and movement.
- Cracked or failed glazing seals. Water or fog gets between panes, and seals around the frame let water in.
- Condensation mistaken for a leak. Moisture forming on cold glass indoors, then running down the frame.
- Ice dams and snow buildup. Snow piles against the uphill side, and meltwater backs up behind it.
- Hail damage. Cracked domes, broken glass and dented metal around the frame.
Leak or condensation?
Winter drips from a skylight are often condensation, not a roof leak, and the fix is completely different.
Calgary’s air is dry, but indoor air still carries moisture from cooking, showers, plants and humidifiers. When that air meets cold glass during a deep freeze, it condenses. Poor airflow in a bathroom or a poorly insulated light shaft makes it worse. Condensation is often tied to attic and home ventilation, which we cover on our roof ventilation page.
| Symptom | Likely cause | Fix |
|---|---|---|
| Frost or droplets on the inside of the glass on very cold days | Condensation from indoor humidity | Lower humidity, run exhaust fans, improve airflow |
| Water or fog between the panes | Failed glazing seal | Replace the skylight unit |
| Drip during rain or a chinook melt | Failed flashing or sealant | Re-flash or replace the skylight |
| Stain on the uphill side of the light shaft | Snow buildup or ice dam at the head | Re-flash with ice-and-water shield; manage snow and ice |
| New drip right after a hail storm | Cracked dome or glass | Replace the unit and check the flashing |
| Damp shaft walls with no visible drip | Warm air leaking into a cold shaft | Seal and insulate the shaft, check ventilation |
Replace or re-flash an existing skylight?
Re-flashing makes sense when the skylight itself is sound; replacement makes sense when the unit is old, fogged or damaged, or when the roof is being replaced anyway.
| Situation | Better choice |
|---|---|
| Unit in good condition, leak traced to flashing or sealant | Re-flash |
| Fog or moisture between the panes | Replace |
| Cracked, crazed or yellowed plastic dome | Replace |
| Leaking or rotted frame or curb | Replace, rebuild the curb |
| Skylight as old as, or older than, a worn roof | Replace during the re-roof |
| Roof being replaced within the next few years | Plan both together |
Asphalt shingles in Calgary typically last about 15 to 20 years. If your roof is near that point, replacing skylights during the roof replacement is the ideal time: the shingles are already off, and new flashing ties straight into new underlayment.
How we install a skylight
We install every skylight the same way, because each step protects the one before it:
- Plan the location. Position the opening between rafters or trusses where possible and check the framing before anything is cut.
- Cut the opening. Remove shingles and cut the roof deck cleanly to the unit’s rough opening.
- Build or set the curb. Build a square, level curb or prepare the deck for a deck-mounted unit.
- Wrap the opening. Run ice-and-water shield up the sides of the curb and onto the deck so water cannot reach the wood.
- Install the flashing kit. Use the manufacturer’s flashing kit, with step flashing woven into each shingle course along the sides.
- Head and sill flashing. Set the head flashing under the shingles above and the sill flashing over the shingles below, so water always runs outward.
- Install the unit. Fasten the skylight and seal it as its manufacturer directs.
- Coordinate interior trim. Leave the opening ready for the interior light shaft and finishing, which other trades complete.
Skylights and Calgary weather
Calgary weather is harder on skylights than on almost any other part of a roof.
If snow or ice is already building around a skylight this winter, see our pages on ice dam removal and roof snow removal. The same flashing principles apply to chimneys, covered on our chimney flashing repair page.
Sun tunnels for hallways, bathrooms and closets
A sun tunnel is often the smarter choice for small, interior rooms without a vaulted ceiling. The roof opening is small, so it fits between framing members without cutting rafters, and the round, low-profile flashing is simpler to seal into the shingles. Because the tube passes through the attic with only a small dome exposed, it loses much less heat than a full skylight and shaft. The trade-off is that you get light, not a view or ventilation.
Removing or covering an old skylight
An unwanted or chronically leaking skylight can be removed and roofed over so the patch performs like the rest of the roof. We take out the unit and its flashing, frame the opening, install new roof decking matched to the existing sheathing, then add ice-and-water shield, underlayment and shingles woven into the courses around it. The ceiling, insulation of the old shaft and interior finishing are handled by other trades.
Energy and comfort
A skylight affects comfort as much as light. In winter, glass loses more heat than an insulated ceiling, so low-e glazing and a well-insulated, sealed light shaft matter. In summer, a south- or west-facing skylight can overheat a room, which is where shades, venting units and careful placement help. North-facing skylights give softer, steadier light with less heat gain. A sun tunnel keeps losses smallest for the light it delivers.
What affects skylight installation cost
Skylight installation cost depends on the unit and on how much roof work the opening needs:
- Skylight type and size. Fixed, venting, powered and tubular units differ in price and labour.
- New opening vs replacement. Cutting a new opening takes more work than swapping a unit into an existing one.
- Curb and framing. Building a new curb or reframing between rafters adds labour.
- Roof pitch and access. Steep, high roofs need more safety setup.
- Flashing kit. Each unit needs its matching kit, step flashing and ice-and-water shield.
- Interior finishing by others. Light-shaft drywall, paint and electrical work are separate.
- Combining with a re-roof. Doing skylights during a roof replacement avoids opening new shingles later.
Ready to talk it through? Book a free inspection or contact us with your questions.