What Melbourne's weather and houses mean for a skylight
Hot days are more frequent
Melbourne hit 46.4 °C on 7 February 2009, and occasional days of extreme heat have become more frequent since 2005. The Australian Government's Your Home guide says roof glazing takes in almost twice as much heat as an unprotected west-facing window of the same size. A skylight that's too big will cook the room on those days.
Cool winters, colder in the hills
In the Dandenong Ranges, snow typically falls a few times a year above 500 m. Your Home says sloped glazing loses heat about 40% faster than vertical glazing, so in a Melbourne winter, a poorly rated skylight is a cold spot. Outside NSW, the National Construction Code limits roof lights to a total of 5% of a habitable room's floor area, with a Total System U-value of U3.9 or less.
Terraces get their light from the top
Melbourne's 1850s to 1890s terraces share walls with their neighbours, so middle rooms often get little daylight, and their roofs sit behind decorative parapets. In a Heritage Overlay, such as parts of Fitzroy, Carlton and East Melbourne, Victoria's planning rules need a planning permit to alter a building's outside, so talk to council even if the skylight won't be seen.
Bushfire areas have extra rules
Your Home says skylights in bushfire areas must comply with AS 3959 for the home's Bushfire Attack Level. In the Dandenong Ranges or on the fringe, ask for a product rated for your BAL.
Tubular skylight or roof window?
Your Home suggests about 1 to 2% of a room's floor area for a high-performing tubular skylight, and about 3 to 5% for a conventional skylight or roof window. It says tubular skylights work best in sunny, clear climates, while roof windows and conventional skylights suit cloudier skies, so think about how much direct sun your roof gets.
Tubes suit hallways, bathrooms and laundries. A roof window gives you a view and, on opening models, ventilation. Our guide to skylights for pitched roofs goes into the differences.
Questions to ask a Melbourne skylight installer
- What are the product's U-value and SHGC, and does it have a WERS rating?
- How big should it be for this room, given the heat in summer?
- Which flashing kit suits my roof type and pitch, and does it rely on sealant?
- On a metal roof, are you licensed for roofing (stormwater) work, and will you fit a head gutter above the skylight if the pitch is low?
- Is the product rated for my BAL, if I'm in a bushfire area?
- Who covers the installation warranty, separate from the manufacturer's?
If it were our house
For a hallway or bathroom, we'd fit a tubular skylight sized to the room and leave it at that. For a living area, we'd choose a well-rated roof window, keep it smaller than feels natural, and add a blind for February heat. If an old skylight is being replaced on an older home, we'd ask whether its frame or surround might be asbestos cement first. Our national skylights page covers types, and the Melbourne hub covers the rest of the local picture.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.
