Mark installs a shed base; Tom and Nathan talk framing; Nathan installs bifold doors.

Mark McCullough travels to Detroit to help a homeowner make a gravel foundation for a shed; Tom Silva and Nathan Gilbert walk through the anatomy of framing an interior non-load bearing wall with a door opening and share their tips on how to build one; then Nathan helps a homeowner hide their laundry area by installing a partition wall with bifold double doors.