Because of naturally occurring chemicals in the wood, there’s no need to treat external cedar cladding. As with all-natural products, cedar cladding will age and change appearance over time. In most areas of the UK, this will mean untreated cedar cladding will weather to a dark grey colour. You can if you wish to use stains, preservatives and other wood treatments for cosmetic reasons. The original colour of external cladding can be maintained by treating it with a UV blocker