A new prefinished oak floor is installed in the kitchen at the 1928 brick Tudor house in Lake Forest, Ill. Meanwhile, homeowner Heidi Smith and interior designer Suzanne Cederlund show host Steve Thomas the plan for the kitchen design; and Thomas, contractor Tom Silva and architect John Krasnodebski discuss ways to minimize the transitions between drywall and brick in the new eating area. Then, in “Ask This Old House,” contractor Tom Silva puts up crown molding and plumbing-heating expert Richard Trethewey installs insulation to keep pipes from freezing.