On 13/03/2015 22:03, JimK wrote:
/ The question is, what would be the best
material for a 'fit and forget' solution?/q

Depends how you want it to look....

Cedar shingles?

Treated featheredge/shiplap?

Jim K

I was sort of thinking that pretty much any timber in full sun is likely
to shrink then, probably, split etc.