On Monday, 9 May 2016 22:22:11 UTC+1, Adrian Caspersz wrote:
On 09/05/16 05:49, wrote:

I'm planning an extension to my house, and want to make flat roof that will last a long time,

I have a southwards facing laid bitumen roof on the extension with a
small bit of a slope. When the sun is in full effect, it's melting and
slowly drifting over the edge, and even things like discarded grass from
birds nest manages to imprint itself. I daren't walk on it. It's painted
with aluminium heat reflective paint, but I'm not hopeful this is a long
term solution for water tightness.

that's unusual.

One way to get longevity is to give the roof just a slight slope and use overlapping asbestos boards (or equivalent), then felt or tile it.


NT

I'd go fibreglass.