Plot: Host Kevin O'Connor arrives in Weston and finds a busload of masons just in from Wisconsin to help with the exterior stone veneer, while general contractor Tom Silva shows homeowner Amy Favat the new synthetic slate roofing material made from 80 percent recycled content. On the outside of the building, Jason Buechel and his crew install a New England fieldstone natural stone veneer that goes up with dark grout and deeply raked joints to give it a dry-laid look