What the spouting makers actually say
Dimond and NZMRM's reasoning is simple. Finer particles still collect on the base of the spouting under a guard, and wet debris and rotting leaves held against the metal can speed up corrosion of the spouting and the ends of the roof sheets.
Warranties come into it too. Dimond says ponding in a gutter should drain or dry within hours or it may affect the material warranty, and the COLORSTEEL warranty excludes damage from contact with other metals and wet contact with stainless steel. A guard is one more metal sitting on your spouting, so what it's made of matters.
PVC spouting is a slightly different case. Marley says its uPVC won't rust or corrode, so the corrosion worry is smaller, but Marley still asks for leaves, silt and debris to be cleared regularly. A guard shrinks that job. It doesn't remove it.
When a guard earns its place
Big trees that drop all year. Pines and some natives can fill spouting faster than a yearly clean keeps up with. Trim first, and if it still fills, a guard can help.
Two-storey homes. Every clean means scaffolding, a mobile platform or a roofer at the edge, so fewer cleans can justify a guard, as long as someone still checks it.
Drinking water off the roof. Less leaf litter rotting in the spouting means less washing toward the tank. Pair the guard with a leaf diverter or first-flush device at the downpipe.
When we'd skip it. Light leaf fall on a single-storey house, spouting that's already leaking or sagging, or an old cement-sheet roof that hasn't been tested for asbestos.
What fitting a guard involves
A good installer starts with the spouting, not the mesh. They clean it out, check the fall and fix leaks and loose brackets, because a guard over failing spouting just hides the problem.
The mesh then runs from the front lip of the spouting up onto the roof, finished with a trim shaped to your roofing so there are no gaps at the corrugations, ribs or tiles. On tile roofs the bottom row is often lifted and re-set. Take care with decramastic: Gerard and Resene say pressed metal tiles made before the early 1980s may have asbestos in their coating.
All of this happens at the roof edge, and WorkSafe says single-storey homes need the same level of fall protection as two-storey ones. Our guide to gutter guards for NZ roofs compares mesh, brush and clip-on types roof by roof.
What a gutter guard quote should spell out
- The mesh material and hole size, by product name
- What the fixings are made of, and whether any go through the roofing
- The trim for your roof profile, and how the gaps at the ribs or tiles are closed
- Whether the guard unclips so the spouting can still be cleaned and washed
- A spouting clean, fall check and any repairs before the mesh goes on
- How they'll work safely at the edge of your roof
- Whether it affects your roof or spouting warranty, in writing
- What upkeep the guard itself needs
Living with a guard
Plan on a check and clean at least once a year anyway: leaves brushed off the mesh, fine sludge cleared from underneath, outlets checked. Our gutter cleaning page covers what a proper clean includes.
Near the coast, washing matters more. The metal roofing industry's Code of Practice says parts of a building the rain rarely washes collect salt and dust and corrode faster. Spouting under a cover becomes one of those parts, which is why a guard that lifts off matters.
A guard doesn't shift responsibility either. The Insurance Council says insurers don't treat overflow from blocked gutters as sudden damage, guard or no guard.
What you can do, and what's for an installer
You can
- Working out which trees drop on the roof, and when
- Finding out whether your spouting is PVC or metal, and what the roof is
- Trimming branches from the ground, or paying an arborist for big trees
- Keeping a downpipe leaf filter clear if it sits at ground level
Leave to a roofer
- Fitting mesh along the spouting and onto the roof
- Lifting and re-setting edge tiles
- Fixing the spouting before a guard goes on
- Anything on or near a roof that might be asbestos
Our honest take on gutter guards
We'd trim the trees and put the spouting on a cleaning schedule before spending anything on a guard. If it still fills too fast, we'd choose metal mesh that unclips, with the mesh, fixings and trims named on the quote and the installer's view on the warranty in writing. On PVC spouting with light leaf fall, we wouldn't bother.
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