What can I line a wooden rabbit hutch with?

I'm thinking oif getting rabbits and was planning to get a metal one but I was told it could heat up in Summer which is really hot here in Australia so I was advised to get a wooden one but appently rabbits can chew any ledges that stick out. I read in a book that any ledges sticking out should be lined for insulation and to stop the gnawing but it didn't say what to line it with. What would I line it with and how would I go about it?