Hi, we are having a dormer loft extension built which needs to have a flat
roof. My late father was in the building trade and then a surveyor and
always swore to avoid them like the plague. Our prospective builder has
however told me that things are 'much better these days' and they offer a 25
year guarantee on a GRP flat roof.

We live on a very exposed area of coastline where the roof would be subject
to a great deal of UV and windy weather (although the prevailing wind comes
from the opposite side of the house.

Does a GRP (fibreglass) roof sound like a good idea, or is there another
material that might be more appropriate - i.e. do an equally good job at
less cost and/or need 'even' less maintenance?

Thanks in advance for any help.

Keith