Tom teaches a homeowner how to replace split-level stair treads in his mid-century modern home; Jenn shares tips about pruners; Richard shortens a gas pipe for a new stove that does not fit against the wall because it is getting stuck on the pipe.

Roger and Jenn share tips for killing weeds without hurting the lawn; Mark restores a historic fireplace that is built with custom bricks; Richard and Ross discuss improvements to thermostats; Tom adds structure to a porch to safely hang a swing.

Ross tests a smart stud finder; Nathan travels to Oregon to repair a wood floor that was burned from a hot iron; Tom shares the best techniques to use a table saw safely; Jenn replaces and improves foundation plantings that were crushed by snow.

Mauro brightens a dark apartment using paint concentrations; Mark and Richard discuss what naturally causes wet basements and how to mitigate it; Tom and Kevin build a bat house.

Jenn helps a couple reimagine their yard after removed trees changed the shade pattern; Richard shares his love of teaching and gives Kevin a tour of his new HVAC distribution and education center.

Jenn helps a couple reimagine their yard after removed trees changed the shade pattern; Richard shares his love of teaching and gives Kevin a tour of his new HVAC distribution and education center.

Mauro brightens a dark apartment using paint concentrations; Mark and Richard discuss what naturally causes wet basements and how to mitigate it; Tom and Kevin build a bat house.

Tom repairs a rotted porch post. Richard visits New Orleans, Louisiana, to help a family deal with high indoor humidity. And the guys ask, "What is it?"

Tom helps a homeowner fit a box spring mattress up a narrow staircase. Kevin and an electrician repair a light switch in Seattle. Richard shows many options for filtering drinking water. And the guys ask, "What is it?"

Lee revives a homeowner's garden bed; a New Hampshire painter shares how she got into the trade; Heath installs a bathroom fan in a house with bad wiring.

Mauro brightens a dark apartment using paint concentrations; Mark and Richard discuss what naturally causes wet basements and how to mitigate it; Tom and Kevin build a bat house.

Mauro brightens a dark apartment using paint concentrations; Mark and Richard discuss what naturally causes wet basements and how to mitigate it; Tom and Kevin build a bat house.

Richard helps a homeowner in New Hampshire quiet a squealing shower. Kevin installs a DIY-friendly security system and video camera. And the guys ask, "What Is It?"

Roger shows Kevin how to start plants from seed. Richard replaces an outdoor hose spigot with one that will never freeze. Tom builds a moveable kitchen island with Kevin. And the guys ask, "What is it?"

Roger helps a homeowner plant a low-cost, low-maintenance privacy screen. Tommy demonstrates many uses for a speed square. Richard uses new technology to seal ductwork from the inside. And the guys ask, "What is it?"

Ross helps a homeowner install a smart thermostat after discovering a wiring issue; Mauro shares his tips on staining a deck to protect and maintain it; Mark helps a homeowner clean a bluestone patio.

In this special program, the guys celebrate 300 episodes of ASK THIS OLD HOUSE by looking back at some of their best moments and revealing some behind-the-scenes secrets.

Lee revives a homeowner's garden bed; a New Hampshire painter shares how she got into the trade; Heath installs a bathroom fan in a house with bad wiring.

Tom and Kevin build a simple table from solid fir, and Kevin works with a wood-finishing expert to stain and finish it. Roger shows a homeowner how to get rid of tree stumps. And Richard discusses the state of solar energy.

In this special episode, the guys make several important improvements. Kevin helps make a home accessible for a homeowner in a wheelchair by modifying a bathroom and several different sets of stairs. Tom and Kevin rebuild a dangerous staircase for a survivor of the Boston Marathon bombing.

Electrician Scott Caron replaces outdated fluorescent under-cabinet lights with new LED fixtures. Roger and Kevin demonstrate how to work with concrete. Richard teaches Tom about the energy-saving potential of temperature setbacks on thermostats.

Ross discusses IAQ testing; Mark restores a Victorian firebox; Jenn and Lee discuss transitioning landscapes from Spring to Summer; Tom, Kevin, and Zack Dettmore organize a tool storage cabinet.

Ross helps a homeowner install a smart thermostat after discovering a wiring issue; Mauro shares his tips on staining a deck to protect and maintain it; Mark helps a homeowner clean a bluestone patio.

Ross helps a homeowner install a smart thermostat after discovering a wiring issue; Mauro shares his tips on staining a deck to protect and maintain it; Mark helps a homeowner clean a bluestone patio.

Ross discusses IAQ testing; Mark restores a Victorian firebox; Jenn and Lee discuss transitioning landscapes from Spring to Summer; Tom, Kevin, and Zack Dettmore organize a tool storage cabinet.

Ross discusses IAQ testing; Mark restores a Victorian firebox; Jenn and Lee discuss transitioning landscapes from Spring to Summer; Tom, Kevin, and Zack Dettmore organize a tool storage cabinet.

Jenn heads to Portland to check out the International Rose Test Garden; Nathan helps a homeowner replace damaged bathroom tiles; wrapping up the season, the team reviews comments left by show viewers.

Ross discusses IAQ testing; Mark restores a Victorian firebox; Jenn and Lee discuss transitioning landscapes from Spring to Summer; Tom, Kevin, and Zack Dettmore organize a tool storage cabinet.

Ross discusses IAQ testing; Mark restores a Victorian firebox; Jenn and Lee discuss transitioning landscapes from Spring to Summer; Tom, Kevin, and Zack Dettmore organize a tool storage cabinet.

The team discusses tools that make good gifts; Jenn returns to her home state of Florida to help a homeowner design a tropical landscape for his backyard; former apprentice Nathan returns to help Tom change the swing of an entry door.

Mark replaces a chipped brick in a fireplace surround and then Mauro updates it with a whitewashed look; Richard shares some advice on maintaining water heaters; Tom demonstrates the importance of a properly installed drip edge.

Tom travels to Colorado to help a couple build a DIY swing set for their young son; Nathan demonstrates how to build saw horses using leftover materials from the job site; in Future House, Ross learns about automated home construction.

Mark replaces a concrete walkway with brick pavers; Richard explains how gas piping is installed in a home; Kevin returns to Upstate New York to build a farmhouse table with maker Jimmy DiResta.

Kevin travels to Portland, Oregon to learn how to protect homes from earthquakes; Mark stains concrete; in Open House, Tom explains why and how to change the locks in a new home; Richard travels to Cleveland to reroute a lengthy dryer vent.

Nathan upgrades a kitchen to have soft close cabinets; Richard and Kevin discuss how gas regulators work and how their malfunctions caused gas explosions in Massachusetts; Jenn cleans up an overgrown garden and redesigns it as a secret garden.

Tom travels to Pittsburgh to replace a bi-fold closet door with one that is more appropriate for the house; Jenn discusses alternatives to flower bouquets that make great gifts; Mauro paints a bathroom using a mold resistant paint.

Jenn installs a vertical garden to maximize space for a homeowner; Tom explains the uses for different drill bits; Richard travels to a plumbing facility in New Jersey to learn about advances in toilet engineering that will help save water.

Heath helps a homeowner install remote controlled patio string lights over their backyard patio; Mauro color matches and repaints a homeowners retro aqua kitchen cabinet; Tom talks through specialized levels for different types of projects.

Mauro helps a homeowner clean up and repaint a rusty metal railing; Richard discusses some innovations that can make clearing a clogged sink easier; Tom and Kevin build a wine rack out of a reclaimed beam.

Jenn partners with an ecologist in Wyoming to learn about prairie grasses and how to care for them; Kevin learns about ways to make a home more resistant against wildfires; in Future House, Ross sees a robotic solar array that mimics a sunflower.

Jenn travels to Orlando to upgrade an irrigation system; the team looks at more Home Inspection Nightmares; Tom discusses kitchen renovations; Kevin returns to upstate New York to build an Adirondack-style outdoor chair with maker Jimmy DiResta.

Richard updates a water filter on a retro faucet; Mark explains the uses for different types of masonry jointers; Nathan explains when and how to use a Japanese pull saw; Tom demonstrates the materials and techniques needed for re-caulking a bathtub.

AskTOH welcomes Landscape Contractor, Lee Gilliam to the cast; Richard helps a homeowner repair a leaking 3-valve shower while retaining the bathrooms original 1930's tile; Lee and Jenn work together to refresh a homeowner's eroding sloped yard.

Roger and Jenn share tips for killing weeds without hurting the lawn; Mark restores a historic fireplace that is built with custom bricks; Richard and Ross discuss improvements to thermostats; Tom adds structure to a porch to safely hang a swing.

Ross tests a smart stud finder; Nathan travels to Oregon to repair a wood floor that was burned from a hot iron; Tom shares the best techniques to use a table saw safely; Jenn replaces and improves foundation plantings that were crushed by snow.

Richard travels to Orlando to diagnose and repair an HVAC system that's creating way too much humidity; Mark demonstrates the best way to build a fire to prevent smoke from filling up the room; Mauro teaches a homeowner how to re-stain a deck.

Nathan heads to Tulsa, OK, to build a replacement utility cover; Ross discusses low-level carbon monoxide exposure and differences in CO detectors and monitors; Mark helps a homeowner clean out creosote build-up in their brick kitchen fireplace.

Jenn helps a homeowner add curb appeal to his house using Victorian plants to match its design; the team shares more home inspection nightmares; Mauro demonstrates how to accurately match paint color; Tom and Kevin hand carve wooden serving utensils.