Season 18 begins with a transformation of a 1940s Rhode Island ranch style home to a Dutch Colonial. In the second half: Nathan installs a barn door; Tom compares roofing materials; and Mark installs a drywell.

Mark and Jeffrey take down a chimney. Scott and Shayla window shop. Exterior walls come down. In the second half: Mauro paints a baby's nursery; Richard tests out a new dryer that uses heat pump; and Tom and Kevin build a record player stand.

Installation of engineered lumber. Window is cut into basement. Staircase design options. Kevin visits lumber factory. In the second half: Jenn plants a small herb garden; Richard reconnects a radiator; and Mark replaces a fireplace.

Raising roof cheeks and second floor walls. New apprentices arrive as part of the Gen Next program. Engineering for a septic system. In the second half: Richard travels to UT to install ductless humidifier; and Ross discusses electric bills.

Apprentices frame deck, install window. Jeff makes flair detail. Jenn visits quarry. In the second half: Tom repairs a built-in with hand tools; the team shares more home inspection nightmares; and light installation.

Staircase is built. Kevin visits Idea House. Tom and Jeff work on the main staircase. Richard tours a factory to see how a furnace is built. In the second half: Tom checks out a women's-only DIY class; and Jenn plants a terraced garden.

Tom and Jeff build ceiling. Local granite cut to size. Complex septic system installation. How interior doors are built. In the second half: Heath replaces toggle switch; affordable drilling and installation of geothermal heat pumps.

Propane tank goes in. Composite decking. Finalize ceiling. New shelving system. In the second half: Ross reviews indoor air quality; replaces polybutylene piping with conventional PEX; and methods for silencing a squeaky door.

Jeff installs floating mantel. Norm panels. Kevin visits apprentices at timber framing school. And then on Ask This Old House, Tom replaces railing with modern cable railing; Nathan upgrades door; Mauro helps homeowner clean and paint shutters.

Old pine boards and panels get new life. A pergola is built and new shutters get assembled.