Toilet Flange Repair, Gas Mower Tune-Up, and a Hidden Bookcase Speakeasy Door: Ask This Old House S24E11

Season 24, Episode 11 of Ask This Old House spends its hour on three things nobody looks at until they break: the wax seal under a toilet, the carburetor on a mower that sat all winter, and a wall in a Cape that is supposed to hide a door. Richard Trethewey handles the plumbing, Lee Gilliam handles the small engine, and Nathan Gilbert handles the framing. The through-line is preparation — the parts of each job that happen before anything looks finished.

Richard Trethewey and the toilet flange: the seal you never see

Richard starts where most homeowners stop thinking. The closet flange, that ring of PVC (or cast iron, or stainless) bolted to the floor around the drain, is doing two jobs at once. It connects to the pipe, but it also anchors to the building. Richard's point is blunt: you don't want to trust the pipe to hold the torque of a toilet. You want the floor framing to do that. A rocking toilet is not a cosmetic annoyance; it deforms the wax ring, and a deformed wax ring is a sewer-gas leak with a bathroom attached.

He walks Kevin through the standard arrangement: the horn on the bottom of the bowl, the wax seal, the two closet bolts that come up through the flange and hold everything down. Fine for a typical floor. Then he creates the problem that sends people to the phone. Add 3/4-inch underlayment to raise the grade, maybe to kill a threshold, and the gap grows. There are wax rings with a horn that buy you about 3/4 of an inch, which Richard calls the edge of workable. Push higher and you're into flange shims — stacked, and glued if you want them watertight — with a conventional wax seal on top. Kevin notices the failure mode immediately: once you build up, the original bolts no longer come through the flange, so there's nothing to bolt the toilet to.

The kit Richard introduces solves that with hardware rather than improvisation. It has its own flange and a rubber seal instead of wax. The bolts are longer, with rectangular bases that slide in and then resist pulling up when you turn them, and plastic tabs hold the bolts upright so they don't flop while you're lowering the bowl. Richard demonstrates the action with the toilet coming down — you can see the seal compress like a shock absorber, keeping contact even if the toilet moves slightly above it, while the bottom stays a positive seal. Longer bolts can be cut to height with a saw and capped. He puts its useful range at roughly an inch to an inch and a half of build-up, and says smaller gaps are still fine territory for a wax ring and shims.

What the segment can't show is the part that decides your project. Before buying any kit, you're pulling the toilet, and that means wax residue, corroded closet bolts, and a look at whether the flange itself is cracked or the subfloor around it is soft. A rubber-seal kit addresses height and slight movement. It does not repair rot. Richard's joke about calling a plumber lands because the real alternative here is cutting pipe below the floor and rebuilding the connection, and that is a different trade of job. If you've been following the season's maintenance thread, this belongs next to the neglected anode rod from S24E9 — another case where the cheap part nobody inspects is the one that fails first.

Lee Gilliam on gas mowers: fuel, air, spark, and the gunk in the bowl

Lee frames small-engine diagnosis in three words: fuel, air, spark. Kevin points out the same logic covers snowblowers, weed whackers, and gas blowers, and Lee agrees — anything with a carburetor. That's the useful thing about this segment. You aren't learning to fix a mower. You're learning a triage order you can apply to a machine you haven't started since October.

Air first, because it's easiest. Lee holds up a clean air filter, then explains that after a season or two it turns gray and loaded. You can blow it out; a replacement is cheap enough that the decision isn't agonizing. Underneath sits the carburetor, fed by the fuel tank, and that's where the real diagnosis happens.

The fuel sample is the money shot. Lee shows a jar with a gel-like layer at the bottom and something thinner on top. That separation comes from moisture, condensation, and ethanol in modern pump gas. Kevin calls it correctly — that mixture won't run, and it will gum up the carburetor on its way to not running. Lee's prevention is fuel stabilizer mixed at the ratio on the bottle, and he and Kevin also handle a can of ethanol-free gas, which Kevin admits he favors for equipment that sits a lot. Gallon for gallon it costs more, and Kevin says so on camera rather than pretending otherwise. If you store a mower for months, that price difference is cheaper than a carburetor.

For a machine that's already gummed up, Lee drains the carburetor bowl through the bolt underneath and dumps the old fuel into a container for proper disposal. Kevin sees granular grit in the bottom of the drained fuel, which is the visual argument for cleaning the jets and ports rather than just refilling. Lee uses a small pipe-cleaner-style brush on the passages, then shoots carburetor cleaner through them — it evaporates fast, which is why it works as a flush rather than a solvent bath. Reassembly is straightforward, and the segment is honest that the fiddly part is the cleaning, not the removal.

Spark comes last. Lee compares a new plug to a carbon-fouled one, then to a plug that's genuinely done — this one missing its electrode arc entirely, which raises the ugly possibility of the missing piece being somewhere inside the engine. That's a small-engine shop trip, not a driveway fix. For the merely dirty plug, cleaning can buy time. The inline tester is the tool worth knowing about: it plugs onto the plug, the mower's cap goes onto the tester, and if the light glows while you pull the cord, you have spark and can stop suspecting the ignition. Oil is the last item. Lee keeps oil separate from the gas mix because people confuse the two, shows clean versus black oil, recommends an annual change for weekly use, and offers the detail I've seen overlooked most often — oil the gasket on a new oil filter before installation, because a dry gasket is nearly impossible to remove later.

Nathan Gilbert's hidden bookcase door: a bar closet becomes a speakeasy

Brett's 1980s Cape had a closet that was doing duty as a fully stocked bar, beer steins included. The plan is a classic speakeasy: a double hidden door swinging out, painted to blend into the wall. Nathan's first questions are the right ones. Is the wall load-bearing? Brett says a structural engineer confirmed it isn't. Has power been handled? An electrician killed it before work started. Nathan also notes there's no plumbing in the wall. Three checks before a saw touches drywall, and none of them are the fun part.

Layout consumes more time than the edit suggests. The kit is 70 inches wide and 80 inches tall, but the rough opening needs to be 72 by 82. Nathan centers on a 92 3/4-inch wall, marks 46 3/8, measures 36 inches each direction, and verifies he has his 72. He pulls a plumb line for the opening edges and measures 82 inches up from the finished floor, because the kit sits on a threshold. Then he transfers the layout to the inside of the wall.

He cuts drywall with an oscillating tool set about a half-inch deep, with a vacuum rigged for dust. With the studs exposed, he removes the common studs but leaves a 3-inch mark at the top for a header package — two 2x4s on the flat, tucking up behind the drywall. He's careful with the language here, describing it as a non-load-bearing header that supports trim and drywall rather than carrying a floor above. Then his framing mock-up does the teaching: bottom plate, king stud, jack stud, header, the former common stud now serving as a cripple stud, and the double top plate above. King studs go in first, then the header, then jack studs underneath so he isn't fighting the header into place.

The kit itself arrives broken down: threshold, left leg, right leg, a header across the top, and hinges with pins that have to align with the doors. He glues and screws the assembly, checks level and plumb, and shims with cedar shims ripped to 2 inches, tucking a fat end and a skinny end into the void until it's filled, then screwing through top, middle, and bottom. The doors go in right first, then left, and the latch sets them. Brett notes the bookcase will hold a lot of books, which is the correct response.

The final step on camera is disassembly for primer and paint so the unit can vanish into the wall. This is Nathan's third door-adjacent project I've written about this season, after the solid-core swaps in S24E8, and the pattern holds: the slab or the kit is the least interesting variable. Square rough opening, patient shimming, correct swing. Get those wrong and a hidden door reads as a cabinet that never quite closes.

DIY Confidence Scale

• Gas mower tune-up: high. Air filter, spark plug, oil change, fuel stabilizer, and draining old gas are all homeowner work with basic tools. Cleaning carburetor jets is still homeowner-able, just tedious. The ethical limits are real: dispose of old fuel properly, and stop if a spark plug is missing its electrode.
• Toilet flange kit: moderate. Installing a rubber-seal kit is not harder than setting a toilet on a wax ring, and the longer bolts remove some of the frustration. The moderate rating is for what you find underneath. Cracked flanges, rotted subfloor, or a cast-iron flange in poor shape move this to a plumber.
• Hidden bookcase door: advanced. Layout, drywall cutting, reframing with king and jack studs, shimming a double door into plumb, and a paint-grade finish stack up fast. The electrical disconnect alone should tell you whether this is your project.

If you take one thing from the hour, take the fuel stabilizer. It's the cheapest item on the list and the one most likely to save an engine from becoming scrap metal.

Additional Resources

• Watch the full episode on PBS
• Official This Old House episode page

Which of the three would you actually start on a Saturday — the seal under the toilet, the carburetor bowl, or the wall you'd have to reframe before the fun part arrives?