The Old Tradesman

The tips library

Setting a toilet

A toilet is china, wax and a handful of nuts, and every one of them punishes too much wrench. Here's how I set one so it doesn't rock, leak or crack, with each number from the maker's sheet.

Tip 1

The flange sits on the finished floor

The trick

Closet flange on top of the finished floor, tile and all. Flush with it or a little below? Oatey says use a thicker wax ring or flange spacers.

Toilet flange on the finished floor Two cut away views of a toilet flange. Right: the flange sits on top of the finished tile floor and the wax ring is squeezed between the flange and the bowl horn. Wrong: the flange sits below the tile, leaving a gap the wax ring cannot fill or compress. CLOSET FLANGE, CUT AWAY Bowl horn Wax Tile Subfloor RIGHT: flange on the finished floor. gap Tile Subfloor WRONG: flange under the tile. The wax cannot compress enough.

Why. Sunk below the finished floor, the flange cannot compress the wax ring enough, and Oatey lists that as a cause of leaks.

The tell. New tile going in around an old flange is how it ends up buried. Check the flange height before the tile is set, not after the toilet is back on.

Fine Homebuilding's plumber says the same: closet flange on top of the finished floor and anchored securely.

When to stop. Cracked flange, or a cast iron or glued-in flange that has to come out? That is a cut-and-replace job for a plumber.

Sources

Tip 2

Slots at three and nine, screws into the subfloor

The number

Bolt slots at 9 and 3 o'clock. Anchor the flange through the finished floor into the subfloor with stainless or corrosion-resistant screws, never into tile alone. Mark flange to pipe before you cement it.

Why. Once the solvent cement sets, Oatey says, the flange can't be repositioned. Glue it a few degrees off and the bolts, and the toilet, sit crooked for good.

The tell. Draw one line across flange and pipe on the dry fit. If the line doesn't meet after you glue, you know before the toilet does.

When to stop. Flange already glued in crooked? Cutting it out is a plumber's job. On a concrete slab, Oatey calls for concrete anchors, not wood screws.

Sources

Tip 3

Set it once, lean on it, do not rock it

The trick

New wax seal, lower the bowl over the flange and bolts, then put your full body weight on it. Kohler: do not lift or rock the bowl after placement. Break the seal and you need a new wax seal.

Why. Squashed wax doesn't spring back. Oatey says a wax ring can't be reused once it's compressed or removed, so a lift opens a gap the old wax won't refill.

The tell. Lifting it to check the bolts is the mistake. Line it up on the bolts on the way down and set it one time.

Kohler presses the wax seal onto the bowl outlet; Oatey's flange guide puts it on the flange. Either way it's a new one: Oatey says never reuse an old wax ring, even if it looks intact. Wax-free seals can be adjusted if you have to reset the toilet, Oatey says, and some models can be reused.

When to stop. Bowl won't sit flat on the floor even under your weight? Don't pull it down with the bolts. Check the flange height and the floor first.

Sources

Tip 4

Closet bolts: alternate, snug, cut to a quarter inch

The number

Tighten the bowl nuts alternately until the toilet is firmly seated, then stop. Bolt sticking up more than 1/4 inch over the nut? Cut it off, with the china shielded from the saw blade.

Why. Vitreous china doesn't bend. Kohler says overtightening can break or chip it, and American Standard warns the base can be damaged.

The tell. Cranking the bolts to stop a rock is the classic crack. Shim the rock first (see below), then snug.

When to stop. A crack at a bolt hole means a new bowl. No sealant fixes cracked china.

Sources

Tip 5

Tank bolts: back and forth until it stops rocking

The trick

Tighten the tank nuts a little each side, back and forth, until the tank sits level, snug and does not rock. Kohler adds: until the bracket tabs touch the bowl. None of the three sheets gives a torque number, and all three say do not overtighten.

Tank bolts, tightened side to side Front view of a toilet tank on its bowl with two tank bolts and the gasket between. Tighten the nuts a little at a time, left then right, until the tank is level, snug and does not rock. The makers give no torque number and all warn against overtightening. TANK ON BOWL, FRONT VIEW L R Gasket A little each side, back and forth, until it is level, snug and does not rock. Then stop. No torque number on the sheets. All say: do not overtighten.

Why. The tank gasket seals by even squeeze. Crank one side and the tank tilts and loads the china at one bolt; Fluidmaster says overtighten and the tank or bowl could break.

The tell. Set the tank parallel to the wall before you tighten, as American Standard does, and sight it as you go. Chasing a drip by cranking one bolt is how tanks crack.

When to stop. Still dripping at a bolt with the tank snug and level? Take it apart and replace the bolt washers and the gasket. More torque is how it cracks.

Sources

Tip 6

Shim a rocking toilet with plastic, never wood

The trick

Plastic shims, a coin, or a brass or stainless washer under the base until it stops rocking. Tighten the bolts alternating sides, then trim the shims flush.

Why. A bowl that rocks works the wax seal loose every time somebody sits. This Old House says never wood or anything that rots, because the floor around a toilet will get wet.

The tell. Rock gone after you leaned on the bolts? It isn't gone, it's loading the china. Shim first.

Fine Homebuilding's plumber shims with rubber gasket material and trims it flush with the bottom of the toilet.

When to stop. Floor soft or sagging around the toilet? Shims won't fix a rotten subfloor. That gets fixed before the toilet goes back down.

Sources

Tip 7

Fill valve: the CL mark sits 1 inch over the overflow

The number

Set the fill valve height so the CL mark on it is 1 inch above the top of the overflow pipe. Water level usually 1/2 inch below the top of the overflow. Refill tube clipped to the overflow, above the water.

Why. Fluidmaster calls the CL height a plumbing code requirement. The CL marks the valve's anti-siphon level: an inch over the overflow, tank water can't rise to it and get pulled back into the supply. And a refill tube shoved down the overflow below the water line siphons the tank into the bowl, its sheet says.

The tell. Short tank? Twist the shank into the valve body to drop it, then measure CL to the overflow before you tighten the locknut.

When to stop. The fill valve locknut gets hand tightened, a quarter turn more only if it leaks (Fluidmaster). American Standard warns an overtightened lock nut can break and flood.

Sources

Tip 8

Half an inch of slack in the flapper chain

The number

Hook the chain to the tank lever with the flapper closed and leave 1/2 inch of slack. Fluidmaster's sheet: chain looks straight, loosen it a bit; looks loose, tighten it.

Flapper chain with half an inch of slack Side view inside a toilet tank: the chain runs from the tank lever down to the closed flapper with about half an inch of slack. If the chain hangs straight, loosen it a bit; if it looks loose, tighten it. FLAPPER CHAIN, SIDE VIEW Tank lever Overflow 1/2 in of slack Flapper, closed Flush valve seat Chain straight: loosen it a bit. Chain loose: tighten it.

Why. A chain with no slack can hold the flapper off its seat. A little slack lets it drop shut every time.

The tell. Look at it with the flapper down. A chain hanging dead straight is too tight.

When to stop. Flapper seat on the flush valve pitted or cracked? A new flapper will not seal it. That is a flush valve change, and the tank comes off.

Sources

Tip 9

Supply nut: hand tight, then half a turn

The number

Metal nut on the shutoff valve: hand tight, then 1/2 turn more (Fluidmaster). Leaks? Just enough more to stop it. The plastic nut on the fill valve goes on by hand.

Why. The seal is the washer inside the nut, not the thread. Past that half turn you are crushing the washer and loading the valve, not sealing better.

The tell. A wrench on a plastic coupling nut is the flood waiting to happen. American Standard warns overtightening the coupling nut can break it. Metal gets a wrench, plastic gets your hand.

When to stop. Shutoff valve that won't close, or weeps at the stem when you turn it? Stop there. Cranking the supply nut won't fix the valve. The stop gets fixed or replaced first, and a soldered one is a plumber's job.

Sources

The Old Tradesman is a cartoon character. Every tip on this page stands on the sources listed under it. He is the voice. They are the authority. The drawings are diagrams, not photographs.

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