Ask This Old House Season 20

Nathan explains the anatomy of track saws; Mark repoints an outdoor pizza oven; The Ask This Old House team comes together for a 20th Anniversary "What Is It?"

Mark explains finishes for brick and concrete; Jenn shows how to maintain a small backyard pond; Tom builds a three-legged Demilune table.

Tom shares a trick to space balusters evenly; Heath shows how to drill holes in studs to run wire; Jenn Largesse builds DIY deck chairs; Richard explains ways to deal with a damp basement.

Mauro shares why he became a painter and what he loves about his job; Jenn shows how to test soil at home; Nathan explains how to use track saws; Heath adds a receptacle to a kitchen island.

Heath shares why he became an electrician and what he loves about his trade; Mauro shows a trick for applying caulk in gaps; Tom shows how to install crown molding around corner angles; Ross explains the future of solar at MIT.

Kevin O'Connor explains how he became host of "This Old House"; a simple trick for drawing a perfect ellipse; moving a light fixture and patching the ceiling; the basics of finish nailers.

Team members talk about their fathers as mentors; airflow in buildings; finishing a baseball bat display case.

Using common electrical tools; an in-depth home energy assessment; painting.

Jenn talks about different types of succulents; Richard installs a reverse osmosis under-sink water filter; Tom builds a classic milk stool.

Richard shows how to replace a toilet seat; Jenn Largesse builds a pergola for her backyard; Nathan repairs a century-old full mortise lockset.

Jenn shows off different varieties of hydrangeas; Heath explains types of smoke and carbon monoxide detectors and their functions; Mauro refinishes deck railings and posts.

Ross shares why he became an engineer; Tom talks about different types of hammers; Richard shows how to control common plumbing emergencies; Nathan removes and replaces a garage door.

Nathan shows how to mount a flat screen TV on a wall. Mark builds a stone birdbath. Tom repairs a Newel post damaged by a dog.

Jenn Nawada suggests houseplants for areas of shade, partial shade and sun. Heath explains techniques for drilling holes to run electrical wire. Jenn Largesse shows how to put up an outdoor vinyl fence. Tom builds a beehive out of wood.

Nathan shares how he became a carpenter and what he loves about his trade; Heath talks all about different LED light bulbs; Richard fixes a wobbly toilet and repairs a sticky faucet handle.

Nathan demonstrates different ways to fix scratches on wood furniture; Jenn Largesse oversees the installation of a shipping container pool in her backyard; Tom shows how to fix and resecure a sagging fence gate.

Tom shares how he became a general contractor and what he loves about his trade; Heath and Ross explain what smart electric panels are and how they work; Jenn and Nathan build and fill new window flower boxes.

Heath breaks down the basic voltages of cordless tools; Richard gives an overview on how to handle simple clogs in a bathroom sink, kitchen sink and toilet; Mark repairs a fireplace and replaces its cover.

Jenn Nawada explains how you can compost at home; Jenn Largesse and her landscape contractor install a concrete block retaining wall in Jenn's backyard; Tom constructs custom built-in drawers, cubbies and shelves for a front hall closet.

Nathan gives a tour of his highly organized truck; Richard shows different kinds of bidets and their functions; Mauro explains how to use spray paint for small home projects; Mark replaces an old, patched driveway with a new concrete one.

Jenn visits a nursery to learn how shrubs are planted and harvested; Ross and Nathan show cost-effective ways to air-seal your windows this winter; Tom demonstrates how to build a serving tray using a box joint jig.

Richard shares how he became a plumber and what he loves about his trade; Ross talks about smart thermostats and their features; Heath explains how to understand switch legs; Tom replaces an old, rotted porch column base.

Jenn and Mark show how to make a stone water fountain for your garden; In Tool Lab, Nathan breaks down Miter Saw blades; The team comes together to discuss the challenges they've faced dealing with ongoing supply chain issues.

Jenn shares the story of how she became a landscape designer; Richard and Ross explain cost-effective ways to save money on your heating bill this winter; Nathan helps a homeowner replace a vinyl kitchen floor.

The entire cast reflects on the 20th anniversary of ASK THIS OLD HOUSE. They'll discuss how the show was made and what they think the legacy of the television program will be moving forward.

Heath explains why finish electrical work is his favorite stage of the job; Mauro demonstrates how to repair a crack in plaster; Mark raises a drywell in a driveway that is sinking below grade.

Mark shares the story of how he became a mason; Tom explains why wood rots on houses, how to prevent it, and how to repair it if it occurs; Ross explores heat pump technology.

In Tool Lab, Nathan explains what different table saw blade types are used for; Ross extends WiFi service in a house; Richard replaces a faulty tub drain; the team shares their New Years' Resolutions.

Jenn explains how to identify and care for holly plants; Richard explains how dishwashers work and how to troubleshoot them when they don't drain properly; Tom and Kevin turn Christmas ornaments.

General contractor and expert woodworker Tom Silva meets past guest and young woodworker Camilla in her dad's shop where they catch up since they last met. After checking out some of Camilla's work, the two discuss her need for a workspace of her own. With a worktable in mind, Tom invites her back to the workshop to help with the special project, a birdhouse.

In Tool Lab, tool expert Chris Ermides demonstrates how tables saw blades work; Heath explains why and how to use a voltage tester; Mark helps a homeowner extend her existing patio.

The entire team comes together to help Mark rebuild the chicken barn he lost to a fire. They reframe the barn, hook up new electrical wiring, connect a utility sink, and hang an exterior door.

Jenn shares her list of must have gardening tools and how to put a garden to bed before winter; Mauro demonstrates how to paint a kitchen cabinet; Nathan installs exterior front door trim.

Mark explains how bricks are made and how many different varieties there are; Richard explains how solderless connections work; Tom assess and reshingles a shed roof with asphalt shingles.

Ross discusses the pros and cons of smart doorbells; Mauro demonstrates techniques for painting wood paneling; Heath shares some of his most-used tools and helps a homeowner install recessed lights.

Mauro demonstrates how to remove dried paint from a paintbrush; Tom shares the best techniques for connecting and installing tongue and groove flooring; Jenn and Nathan build a DIY ice rink.

Jenn discusses creative options for ground cover plants; Tom demonstrates different techniques for patching wall holes; Mark demonstrates how to patch brick holes; Nathan installs a new threshold.

Jenn creates a landscape that can withstand heavy pedestrian traffic; Richard explains the options available for water heaters; Tom and Kevin build a cutting board out of walnut, cherry, and maple.

Richard discusses pipe soldering; Heath explains what two-prong receptacles are, why they're no longer to code, and how to replace them; Nathan and Mauro build, install, and paint deck stair railings.