Hi,

What is the easiest way to fill the channels in the roof of my campervan (before adding a solar panel).  The attached picture shows the size of the channels.  Could I just make a lightweight filler with glass bubbles and fill the entire void?

My assumption is that the roof is GRP sprayed with car spray.  There is a fair amount of flex/twist as the roof goes up and down, although I'd say that is fairly minimal along the ridges themselves.

Many thanks

If you were worried about flex (eg if its a pop up roof), then a final skim with a thin layer of glass blended in would be a good idea.  Otherwise and epoxy based filler should certainly be strong enough if it is a couple of mm thick which is as deep as you would want or need to go. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant