Why gutters overflow on the Sunshine Coast
Hail packs the gutters
After the 17 November 2019 hailstorm, homes and businesses reported interior damage caused by overflowing gutters, on top of broken roofs and solar panels. Hail and shredded leaves block gutters and downpipes quickly, and the rain behind them has nowhere to go.
Heavy rain, and plenty of it
Sunshine Coast Airport averages 1,498.3 mm a year, with February at 217.5 mm and March at 187.7 mm. Gutters that cope with a normal shower can be overwhelmed by a summer cloudburst.
Water on the ground too
Council says inland flooding of creeks, rivers and low-lying plains is a regular occurrence in extremely heavy rain, and can happen any time of year. Downpipes that drain into a saturated yard or a blocked pit will back up toward the house.
What good roof plumbing looks like
The building code wants an overflow route so water spills outside, not into the eaves or walls. Accepted options include slotted gutter fronts, a 10 mm gap behind the gutter, or a front bead at least 10 mm below the top of the fascia. Gutters are sized for the local five-minute rainfall intensity, so the right size depends on where you are.
Box gutters (built into the roof rather than hanging off the edge) and valleys need the most care, because a blockage there sends water straight inside. Under the code, valley gutters belong on roofs pitched over 12.5 degrees. See box gutters and our national roof plumbing page.
Licences and complaints in Queensland
Plumbing and drainage work needs a QBCC licence whatever it costs, and the QBCC can look at plumbing complaints whatever the job's value too. Licensed plumbers must show their licence number in every ad, so check it against the QBCC register.
If the work turns out to be defective, put it to the contractor in writing first, listing each problem and giving them a timeframe, such as 14 days, to fix it.
Questions to ask a Sunshine Coast roof plumber
- Do my gutters have an overflow path, and where does it discharge?
- Are there enough downpipes for my roof area?
- Can you check the valleys and box gutters for blockages and rust?
- Where do my downpipes drain to, and does that back up in heavy rain?
- What's your QBCC plumbing licence number?
What you can watch for
You can
- In heavy rain, look out the window to see where gutters spill
- Keep stormwater grates and ground-level outlets clear
- After hail, check from the ground for downpipes that aren't running
Leave to a roofer
- Unblocking and repairing gutters, valleys and box gutters
- Adding downpipes or overflow slots
- Flashings around vents and skylights
- Regulated plumbing, which needs a licence at any value
What we'd book first
We'd have a roof plumber check the overflow path before anything else, because water spilling inside does far more damage than water spilling over the front. Then we'd get valleys and box gutters cleared before November, when council says the storm season usually starts. The Sunshine Coast hub has more on local conditions.
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.