General contractor Tom Silva finishes up the last of the structural work at the latest renovation. Window restoration specialist Alison Hardy reinstalls the restored historic window sashes in the dining room. This includes adding spring-action hardware and weather-stripping to make them more efficient. In the garage, host Kevin O'Connor finds electrician Allen Gallant upgrading the electrical service to 100 amps so it can function as a workshop. Part of the "This Old House: Trade School" series.