[Greenbuilding] galvalume roofing

[candtcampbell at juno.com]

No Nick,

It's just acrylic to prevent the metal from being scratched before installation.

Tim

It's probably more than just an acrylic, more a pretty serious baked on
finish that can carry warranty up to 36 years. The local product is called
colorbond. It is the coating applied to zincalume plain roofing.

http://colorbond.com/learn/articles/how-is-colorbond-steel-made

Pioneer Water Tanks and Bluescope Water are Australian companies and I guess
the Australian technology is applied in the US.

All new residential construction in this state is required to harvest
rainwater by law, and the proportion of metal roofing is significant. Nearly
all the metal roofing is colorbond. I didn't know zincalume was still
available until I made inquiries for my own use. It isn't much cheaper than
colorbond.

Colorbond is fine for harvesting but not for storage. Colorbond tanks carry
an extra food-grade polymer coating and are called aquaplate. I can't see
much point in this and call for all-poly tanks, which are usually cheaper
anyway.   

I recall the New South Wales Department of Health has a swag of further
information.


-----Original Message-----
From: Greenbuilding [mailto:greenbuilding-bounces at lists.bioenergylists.org]
On Behalf Of candtcampbell at juno.com


Not very long ago on this list there was some discussion that galvalume, or
zincalume as it's called in Australia, is the best roof for harvesting
rainwater. However, in the US, it seems that all galvalume is coated with
acrylic. So I'm wondering what impact that coating has on the water,
specifically whether it has any toxicity?

Tim