Why Cairns gutters fail
Wet and salty, both at once
The QRA says the rate at which steel straps, connections and roofing deteriorate depends on salt spray, moisture levels and coatings. Cairns has plenty of the first two: rain on about a third of the days in a year, and a string of beach suburbs along the coast.
The Northern Beaches
Holloways Beach has needed rock groynes and sand nourishment to fight erosion. Homes this close to the water need the gutter grade checked, not assumed.
Storm debris
When Cyclone Larry passed in 2006, most of the damage in Cairns came from falling trees and power lines. After any big blow, gutters fill with leaves and twigs, and a full gutter holds water against the steel until it rusts.
Water that doesn't drain
The building code asks for a gutter fall of at least 1:500, and BlueScope says gutters need enough fall to avoid ponding. Sagging brackets leave pools that never dry in a Cairns wet season, and that's usually where rust starts.
What to ask for
The right grade. For gutters, downpipes and fascia, BlueScope recommends standard Colorbond or Zincalume more than 200 m from salt marine influence, and Colorbond Ultra more than 100 m away. Closer than that, ask what the supplier recommends.
Slotted fronts or another overflow. Lysaght's Quad gutter comes slotted or unslotted. Slots in the front face let water spill outside instead of backing into the eaves, one of the overflow options the building code accepts.
Compatible metals. BlueScope warns galvanised gutters can corrode early under Colorbond, Zincalume or glazed terracotta roofs, and that stainless, lead and copper don't belong with its coated steel. Joints should be lapped and sealed with neutral cure sealant. Our Colorbond gutters page has more.
In Queensland, gutter installation sits under the QBCC's Metal fascias and gutters licence, and a whole-house job over $3,300 should come with home warranty cover.
Questions to ask a gutter installer
- Which steel grade do you recommend for my distance from the beach, and why?
- Will the new gutters be slotted or have another overflow path?
- What fall will you set, and how far apart are the brackets?
- Is the fascia behind the gutter still sound?
- What sealant and rivets will you use on the joints?
- Can I see your QBCC licence?
What we'd do
Replace the whole run in one go and pay the extra for Colorbond Ultra if you're anywhere near the beaches. Ask for slotted gutters and a fall you can see. Then keep the trees trimmed back, because a Cairns gutter that stays full of leaves will rust no matter what it's made of.
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.
Tell us your suburb and roughly how much gutter you've got, and we'll look for one licence-checked tradie who replaces gutters there. More on our national gutter replacement page and the Cairns hub.