What drain and filler does a freestanding stone tub need?

What drain does a freestanding tub use?

A 1-1/2 in drain with a trap. The IRC trap-sizing table gives a bathtub a 1-1/2 in minimum trap, and Aquatica's stone tub procedure lists a 1-1/2 in tailpiece, male adapter, pipe and trap supplied by the plumber. Kohler's guide calls for a standard PVC or brass drain pipe extending a model-specific height above the finished floor.

The drain pipe rises through the floor and the tub is lowered over it. Kohler's table gives that height as 1/2 to 2-1/8 in depending on the model, so a generic number is not safe. Use the tub's own drawing. Kohler also says to make sure all plumbing connections around the bath are easily accessible for future maintenance.

Does a freestanding stone tub need an overflow?

Some do and some do not. Kohler describes its freestanding bath as having an integral, cast overflow, and Aquatica's stone tub shows a built-in overflow channel. A tub carved without one means the drain assembly must be a no-overflow type and the filler should never be left running unattended.

Confirm before ordering the drain kit. A kit meant for an overflow tub will not seal on a tub without one, and the reverse leaves an open hole. The IRC fixture text says a bathtub discharges through an approved waste outlet and overflow, so ask your plumber and inspector how a no-overflow tub is handled locally.

Should the filler be floor-mounted or wall-mounted?

Choose by where the tub sits. Floor-mounted suits a tub away from walls. Wall-mounted suits a tub against a wall. Kohler's freestanding bath guide says to install a floor- or ceiling-mounted filler. The table lists published figures from Waterworks installation sheets; they vary by model, so use the sheet for the exact filler.

How far should the spout reach over a thick stone rim?

Far enough that the stream lands inside the tub, not on the rim. Waterworks says on each filler sheet to check the tub measurements so the spout projects far enough into the tub. A reference 67 × 31 × 22 in marble tub has 2.5 in walls, which is far thicker than an acrylic rim, and a rolled or sloped top adds more.

A spout reach of 8–12 in, as in the table, can be short for a tub with a wide rim set well away from the filler. Measure from the filler's center to the inside edge of the rim, then confirm the reach clears it with room to spare. Floor-mounted fillers can be placed close to the tub, so the answer is often to move the filler, not change it.

Where should the drain and supplies be roughed in?

From the drawings, before the tub is set. Waterworks says its floor-mounted fillers must be on site before rough-in so the installer can verify the spread, which is not adjustable. Waterworks guides call for well-supported 3/4 in hot and cold supply lines for maximum flow and accessible stop valves, with piping capped off until the filler is fitted.

Aquatica adds that the plumbing and drainage should go in before the unit is secured, and that drain and plumbing should not sit directly above floor joists. Waterworks also advises that some plumber's putty can stain stone, so ask your plumber to use a stone-safe product.

Does the drain need an access panel?

Plan for access. IRC summaries state that fixtures, traps and connections must remain usable and serviceable without removing permanent construction, and many jurisdictions expect access to concealed slip-joint fittings. No single panel size applies everywhere, and local amendments change the details.

The simplest answer on an upper floor is a ceiling opening below, or a floor-level drain with a clear service route. Aquatica strongly recommends access from the floor below. Ask your plumber and building department what your adopted code requires. See the care guide for what to keep off the stone near fixtures.