'Home Improvement' stars Tim Allen, Richard Karn channel 'Tool Time' for History DIY show Bill Keveney, USA TODAY Replay Video UP NEXT If Tim Allen and Richard Karn reuniting for a reality building competition reminds you of their classic sitcom "Home Improvement," that's the point. History Channel's "Assembly Required" (premiering Tuesday, 10 EST/PST) lets the pair "be exactly like we were in 'Tool Time,' " the DIY show-within-a-show in ABC's former hit sitcom "Home Improvement," Allen told a Television Critics Association panel last week. Joined by DIY woodworking expert and YouTube star April Wilkerson, Allen and Karn will oversee a competition between makers across the country as they build a variety of contraptions "from a dual, all-season ice-melter/leaf blower and all-in-one riding comfort mower to a do-it-yourself jacuzzi and BBQ bicycle," the network says.