Roger Cook mulches the planting areas around the finished spa; bushes will give it some privacy. In the dining room, Tommy puts up the final pieces of an elaborate, 11-piece ceiling molding that replicates the house's original detail, while our master carpenter meets cabinetmaker Tom Perkins, who is using a software program to specify the exact components of the many built-ins. He will e-mail a numerical code to a shop in the Midwest, which will efficiently cut all the pieces and ship them to him to assemble and install. Steve gets a lesson in paint preparation from paint contractor Jim Clark, who reveals the many steps necessary to obtain the smooth finish that is he and his crew's trademark. Richard Trethewey shows Steve the latest generation in radiant-floor-heat technology: accordianlike panels that quickly unfold to cover 10 square feet and accept radiant tubing. Finally, Joe Ferrante shows off his tiling work in the master bath, whose steam shower is done up in limestone and marb