best material for guttering

PVC and any other plastic guttering that I've seen usually sags between supports, it's the nature of plastics. Colorbond is better than zincalume as guttering because it tends to resist the acids etc that rotting leaves produce. If you keep your gutters clean then zincalume will last just as long. In order of longevity I'd rate guttering materials thus:
Stainless steel
Copper
Colorbond
Zincalume







Galvanized (painted or not)

Mick

Colourbond is better than anything IMHO, but it's doesn't play nicely with lead flashing's

We get aluminum guttering here.

The guys come out with a truck and a machine. The machine forms the aluminum coil stock into a seamless gutter. The aluminum is painted with a powder coating system before being coiled. The most common colors are white and a poop brown.

The only joints in the entire system are where the down spouts are and corners. I've had these seamless gutters on the house for over 15 years without any problems.

Originally Posted by kiwiclay

Colorbond is just painted zincalume,

Exactly, I think we've touched on this before.
I wouldnt get it extruded on site, the fellas who done a mates mums place hung a length of quad gutter 15m long without any expansion joints and used internal brackets, now it looks like a dogs breakfast due to not being able to expand.
I wouldnt even look at plastic.