Why Adelaide gutters and downpipes get overloaded
Bursts the system wasn't built for
Parts of the suburbs flash flooded in March 2016, and storms like that dump rain faster than a downpipe can take it. The water backs up and spills over the back of the gutter, into the eaves or the wall, where it does the most damage.
Winter hail in the outlets
Hail can fall in Adelaide in winter, not just summer. When it packs into a gutter, it blocks the outlet just as the rain is heaviest, and a gutter that was fine an hour earlier overflows.
Stone homes and hidden box gutters
Much of early Adelaide was built in bluestone. If your older stone home or terrace has a parapet wall, there's usually a box gutter behind it, and when one of those overflows the water goes inside rather than over the edge.
Salt air near the water
BlueScope recommends Zincalume and standard Colorbond gutters, downpipes and fascia more than 200 m from salt marine influence, and Colorbond Ultra more than 100 m. Closer to the gulf, ask what the roof plumber is proposing and why.
What a good roof plumbing job looks like
The national building code sets the basics. Eaves gutters need a fall of at least 1:500 towards the outlets, each downpipe can serve no more than 12 m of gutter, and gutters need overflow measures, such as slots in the front face, so a blockage spills outside rather than in.
Materials have to get along with each other. BlueScope says galvanised gutters can corrode early under a Colorbond or Zincalume roof, so it recommends Colorbond or Zincalume gutters instead. It also says lead flashings and copper run-off, such as a hot water overflow dripping onto the roof, corrode coated steel.
If you collect rainwater for drinking, the code bans lead on a roof that's part of the catchment. Mention your tank when you get quotes.
In South Australia, a business that does or organises plumbing work needs a plumbing contractor's licence (or a building work contractor's licence), and the person doing the plumbing must be a registered plumber. Draining work, including pipes that carry stormwater to the public system, falls under that registration. Plumbing work must be certified with an electronic certificate of compliance, and CBS says defective plumbing is covered for ten years.
What to ask a roof plumber
- Are there enough downpipes for the length of gutter, and are they in the right places?
- Where's the overflow, so a blocked gutter spills outside instead of into the eaves?
- Do my box gutters need relining, or just clearing and resealing?
- Will the new gutters and flashings be compatible with my roof sheets?
- Is my roof suitable for collecting drinking water, and does that change the materials?
- Who's the registered plumber on the job, and will you lodge a certificate of compliance?
Your part, and theirs
You can
- Clear downpipe outlets and stormwater grates you can reach from the ground
- Watch the gutters from inside during heavy rain and note where they spill
- Keep branches trimmed back from the roofline
- Photograph rust, stains and drips to show the roof plumber
Leave to a roofer
- Re-falling or replacing gutters
- Adding downpipes, overflows or rainheads
- Box gutter and flashing work
- Anything that means working from the roof or a ladder at the roof edge
Where we'd start
Watch your gutters in the next heavy rain, from inside where it's dry. If water pours over the front edge, it's a blockage or too few downpipes, and that's a straightforward fix. If it's coming through the eaves or a ceiling, especially on an older stone house with a parapet, we'd get a roof plumber to check the box gutters and flashings before winter.
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.
Finding a roof plumber
Tell us what's overflowing and your suburb. We'll pass the job to one licence-checked roof plumber in your part of Adelaide if we have one, or tell you straight away if we don't. Our national roof plumbing page and the Adelaide hub cover more ground.