In message
,
robgraham writes

Has anyone got any experience with Onduline ?

http://www.ondulinebuildingproducts.net/p0007.htm

Only that it needs a lot of supporting as it lacks the rigidity of
cement fibre.

On the condensation issue.... cement fibre is good because the surface
is porous and can retain some moisture to evaporate off when things warm
up. Steel can be coated with *felt* to a similar effect.

regards

--
Tim Lamb