General contractor Tom Silva and master carpenter Norm Abram install the massive decorative timbers in the new family room. Meanwhile, plumbing and heating expert Richard Trethewey shows host Kevin O'Connor the location for the new A/C condenser and how to set it on a prefabricated concrete mounting pad. Then, Norm visits the Parson Capen House in Topsfield, Massachusetts - a house similar to the Bedford house from 1683 that's been largely unaltered over the years. Back in Bedford, Tom shows Kevin the progress on the new front entry deck and how he's fastening the mahogany deck boards with a new hidden fastening system. It consists of a tool that serves as both a spacer for the boards and a jig for the proprietary screws. In the backyard, homeowner Joe Titlow works with family and friends to install a new garden shed that he ordered online from the home center. At the end of the day, the insulation crew arrives to add closed cell spray foam insulation to the new addition. In the second half of the hour, on ASK THIS OLD HOUSE, Richard travels to Philadelphia to install a battery back-up sump pump. Then Richard, along with Kevin, landscape contractor Roger Cook and Tom, asks, "What is it?" Afterward, Tom fixes a rusty metal railing on a set of front steps. And Kevin shares a tip about how to store a wheelbarrow.