Hi, I know there are so many things to take into account and it's hard to get perspective from a photo. The white you can see is an extension with building paper, and the red is the existing building which is two story. The exterior is wide weatherboard planking, the windows are silver aluminium with very little trim. The doors in the front of the picture are French doors from bedrooms that will open to an enclosed courtyard ( yet to be built of course) The roof will be a light grey/brown but you won't see it much because of the flat roof style. There will be decking and ballustrades covering half of the new extension.

There's a few but Google Sketchup is probably the most available. The thing is, you'd be better off dealing with your architect for this because they would be better to tell you what materials are actually practical, they would know costs, installation times, etc. For example you might not be able to do a lot of masonry in heavy seismic zones and certain other types of cladding may require thicker foundation, etc. Not only that there are a myriad of different ways to stucco a home and so forth. I mean you could use Sketchup to mockup some ideas, but this is work that is honestly best done in concert with an experienced professional.

Also what type of cladding would anyone suggest?

Sorry I am so late coming to your site - you are an inspiration to all, homeowners and advisers alike. For your planting advice, I suggest you call Merrifield Garden Center to see if they will come out your way. They currently have wonderful garden centers in Merrifield and Fairfax (both in Fairfax County) and a new one in Gainesville, but they may come further south to wherever you reside. (www.MerrifieldGardenCenter.com) Even if they don't send designers to your area, they are worth a trip to see their huge selection for a day of pleasure and inspiration, or to pick up some plants. Most of my clients are in the Fairfax and greater Washington area, but I am currently living out west below Front Royal, VA on the Shenandoah mountainside - wonderful views. cascio.offsite@gmail.com