Hello. We are in the process of having Arctic White James Hardie Siding installed through Home Depot. They have only done the actual trim work around the windows and under the soffits so far but I have noticed that most are very dirty. Some pieces are a beautiful white but many are very drab/dingy to the point of looking just as old as our 40 year old siding was. I believe they likely got dirty during shipping and/or while on our driveway for 4 days pre-installation. Does anyone know if I will have to power wash the house right after the siding is complete? Or can you power wash James Hardie siding? Thanks!