The Carlisle, Mass., farmstead. Work proceeds on the barn chimney and ceilings, and on its heating and cooling systems; tiles are laid in the master bath; an electricity generator is installed. Outside, work on the terrace and retaining wall is completed under a heated tent. And host Kevin O'Connor visits an antique-lighting restoration firm. On “Ask This Old House,” projects include yard-waste composting and removing an old cast-iron house trap on a sewer line so that a clog can be cleared.