A skylight can turn a dark hallway or a south-facing kitchen into a room you actually want to sit in. It is also one of the most common places for a roof to leak, because it is a hole in the roof that relies entirely on its flashing. In Christchurch there is a second problem that gets mistaken for a leak: winter condensation running off a cold skylight on a frosty morning.
We install new skylights, roof windows and sun tunnels, and reflash or replace old units, across Christchurch, Selwyn and Waimakariri. If you are planning a re-roof, it is the cheapest time to replace tired skylights because the roof is already open. Our re-roofing page explains how we fit them into that work.
Pricing: every roof gets a free on-site measure and an itemised written quote, with a fixed price agreed before any work starts.
When a skylight needs attention
Skylight leaks are often blamed on the glass when the real cause is the flashing or the roofing around it. These are the signs we check for on an inspection:
- Water stains or bubbling paint on the light well or ceiling around the skylight
- Water dripping on cold mornings but not in rain, which usually points to condensation
- Crazed, yellowed or brittle plastic domes
- Perished seals or rotting timber frames on older units
- Sealant smeared around the upstand, a sign of an earlier quick fix
- Leaves and grit built up on the high side, damming water against the flashing
Leak or condensation: a Christchurch question
Christchurch averages around 80 ground frost days a year, and nights below zero are common in winter, particularly away from the city centre. On those nights the glass of a skylight and the walls of an unlined or poorly insulated light well become the coldest surfaces in the room. Warm, moist air from cooking, showers and drying washing condenses on them and runs down onto the ceiling, which looks exactly like a leak.
The fix for condensation is different from the fix for a leak, so we work out which you have before quoting. Clues include drips on still, cold mornings rather than during rain, and staining that tracks evenly around the well. The answers can include a double-glazed unit, insulating and lining the light well, an opening skylight to vent a bathroom, or better ventilation in the room. A genuine leak needs the flashing addressed. Our roof flashing repairs page covers that side.
How It Works
Types of skylight and roof window
Modern skylights are made for either pitched or flat roofs, and the two are not interchangeable. VELUX, for example, sells separate pitched-roof and flat-roof ranges, each with fixed, manually opening, electric and solar-powered models, plus tubular sun tunnels for smaller spaces such as hallways and ensuites. Opening models clear steam from wet rooms, and electric and solar versions can close automatically when it rains.
The flashing kit has to suit the roof cladding. Standard kits are made for corrugate and tile roofs, and some retailers note they do not suit certain trapezoidal metal profiles. On those roofs, and on membrane roofs, the opening needs a different flashing or a purpose-built upstand. We confirm the right combination before ordering.
- Fixed skylights: the most light, no ventilation, the simplest option
- Opening roof windows: manual, electric or solar, useful in bathrooms and kitchens
- Flat-roof skylights: set on an upstand above the membrane
- Sun tunnels: a reflective tube bringing daylight into small rooms with deep roof spaces
Installing, replacing and resealing
For a new skylight we confirm the position against the rafters or trusses, cut and trim the opening, fit the unit and flashing kit, turn the roofing and underlay into the flashing correctly and line the light well. Where the opening means cutting a structural member, the framing has to be trimmed properly and the work may need building consent.
Replacing an old unit usually means replacing its flashing too, because a new skylight on a tired flashing is a common cause of repeat leaks. If the skylight is sound and only the flashing or seals have failed, a reflash can be enough. On a tile to steel re-roof, old skylights are best replaced at the same time, because the new roof needs flashings made for steel anyway.
Cost factors for skylights
Skylight jobs range from a simple like for like swap to a new opening with a lined light well through a ceiling cavity. Your quote lists each part separately: the product and size, whether it opens and how it is powered, the roof profile and the flashing it needs, any trimming of framing, the depth and finish of the light well, and roof access. Blinds and rain sensors are itemised so you can decide what is worth it. On north-facing roofs, a blind is worth considering for hot nor'west afternoons.
Consent and safety
Work on a roof window in an existing home can be exempt from building consent under Schedule 1, but the exemption has conditions. It does not cover a window installed within the last 15 years that has failed, or work affecting a specified system such as sprinklers or alarms, and structural changes to cut a new opening can change the answer. Where consent is needed, it comes from Christchurch City Council, Selwyn District Council or Waimakariri District Council depending on the address. Our roofing FAQs explain the basics.
Skylights are a fall-through hazard during roof work, and WorkSafe guidance treats roof openings and brittle materials as places that need covers or edge protection. We protect openings while we work, and we recommend you never walk near a skylight on your own roof.
Why Choose Cheeky's Roofers for Skylights
Roofers, not just installers
We flash the skylight into the roofing and underlay properly instead of relying on sealant.
Leak or condensation sorted first
We work out whether water is coming through the roof or forming inside before recommending any work.
Right flashing for your profile
We confirm the flashing or upstand suits your corrugate, trapezoidal, tile or membrane roof before ordering.
Openings protected
Covers and edge protection keep the job safe for our team and anyone below.
Skylights FAQs
Why does my skylight drip on cold mornings but not in the rain?
That pattern usually means condensation rather than a leak. Moist indoor air condenses on the cold glass and light well. Double glazing, insulating the well or better ventilation are the usual fixes.
Why does my skylight leak in the rain?
Most skylight leaks come from the flashing, perished seals or debris damming water on the high side, not the glass. An inspection finds the actual entry point before anything is replaced.
Can you put a skylight in a corrugated iron roof?
Yes. Standard flashing kits are made for corrugate and tile roofs. Some trapezoidal profiles need a different flashing, which we confirm on the measure.
Do I need consent for a skylight?
Work on a roof window in an existing home can be exempt under Schedule 1, subject to conditions. A new opening that changes the structure may need consent. We check before quoting.
Is a skylight or a sun tunnel better?
A skylight suits rooms where the ceiling sits close to the roof. A sun tunnel suits small spaces with a deep roof cavity, such as hallways and ensuites.
Should I replace skylights when I re-roof?
Usually yes if they are older plastic domes or show any sign of leaking. The roof is already open, so replacement costs less than doing it later.
Skylights Across Christchurch
We cover every region: Central Christchurch, North Christchurch, East and Coastal Christchurch, South Christchurch and Port Hills, West Christchurch, Selwyn and Waimakariri.
Related Roofing Services
See the roof replacement cost guide or every service we offer.