How Adelaide's rain finds a weak spot
Rain comes in a season
The airport averages 536.5 mm a year over 121.2 rain days, with June (77.7 mm) and July (71.1 mm) the wettest months. Months can pass without a real test, so small faults build up quietly until winter.
The foothills take more water
Belair, up in the south-eastern foothills, averages 724.0 mm a year and 100.9 mm in June alone. A roof and gutters in the hills handle a good deal more water than the same house down on the plains.
Downpours beat the gutters
Adelaide's wettest day on record dropped 141.5 mm in February 1925, and parts of the suburbs flash flooded in March 2016. When rain falls faster than the gutters and downpipes can carry it, water backs up under the roof edge and looks exactly like a roof leak.
Hail opens new gaps
The January 1991 hailstorm, with stones up to 10 cm across, cracked tiles and left water damage in many homes. Hail can fall here in winter as well, so check ceilings for fresh stains in the wet days after any hail.
Where Adelaide leaks usually start
On a tile roof, look first at the ridge. Monier lists cracked or broken mortar bedding under the ridge and hip caps as a common cause of leaks, along with cracked or slipped tiles. Valleys, where two slopes meet, are next, especially once leaves pile up in them.
On a corrugated roof, it's usually rusted or loose screws, flashings that have lifted around chimneys, skylights and solar mounts, or sheet ends rusting back from the gutter.
Not every stain is the roof. One that grows on cold, still nights with no rain can be condensation, so read condensation or a leak? or try the leak finder before you book.
While it's still dripping
Stay off the roof while it's wet. If water is pooling near light fittings, turn the power off at the switchboard, and keep out of any room where the ceiling is bulging. A bucket and towels tonight, a roofer once it clears.
Questions to ask before they start
- How will you find where the water gets in, and will you show me photos of it?
- Is this a one-off repair, or a sign the whole ridge or valley needs work?
- Could it be the gutter or a box gutter overflowing rather than the roof itself?
- If it still drips after the next heavy rain, will you come back?
- What's included if the leak has wet the insulation?
- Is your licence on the CBS register, and what warranty comes with the repair?
You, or a roofer?
You can
- Note when it drips: every shower, only heavy rain, or only when wind blows from one side
- Mark stains in pencil with the date so you can see if they grow
- Clear blocked downpipe outlets you can reach from the ground
- Look at the roof from the street, or with binoculars, after rain
Leave to a roofer
- Tracing the leak on the roof itself
- Replacing tiles, rebedding ridges or resealing flashings
- Clearing valleys and box gutters
- Anything on a roof that might be asbestos cement
Our take
Get a known leak found and fixed in autumn, before June and July test every weak spot at once. If it only drips in the heaviest downpours, ask the roofer to check the gutters, box gutters and valleys as well as the tiles, because overflow is a common culprit. And if the first roofer can't pin it down, pay for proper leak detection rather than sealant smeared over the general area.
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.
Getting it looked at
Tell us where the water is showing and your suburb. We'll pass the job to one licence-checked roofer working in your part of Adelaide if we have one, or tell you straight away that we can't. For more on the job itself, see roof leak repair, or head back to the Adelaide hub.