How to Replace an RV Tub With a Shower? | Measure, Fit, Seal

Swapping an RV bathtub for a shower pan is a removal-and-replacement job — the new pan or surround must match your rig’s opening and drain.

Most RV tub-to-shower projects stall before a single screw comes loose, and the plumbing is rarely the reason. A replacement pan or surround has to line up with three things: the opening’s footprint, the drain’s side, and the wall structure behind the old tub. The steps are simple enough; sourcing parts that fit is what sinks most projects. Several makers sell direct OEM replacements for standard RV bathtub openings, so a full gut-and-rebuild isn’t always required. Here’s what to measure, the order to pull things apart, and the errors that turn a weekend job into a redo.

Measure Before You Buy: Fitting A Shower Pan To Your RV

Compatibility decides this job, so measure the tub opening and confirm the drain side before ordering. Replacement pans and surrounds ship in fixed sizes, with the drain on the left or right — get either wrong and the part goes straight back.

Three measurements carry the weight:

• The opening’s width, depth, and height, taken at the widest point of the existing alcove.
• The drain side, noted as left or right while facing the tub.
• What sits below the drain hole. A new pan means a new 3″ cut, which has to be clear of frame rails and components.

Sizes cluster around a few standards, which makes comparison easier than it sounds.

If a tub still makes more sense, this roundup of bathtubs built for campers narrows the sizes that fit RV alcoves.

Replacing The RV Tub With A Shower: The Step Order That Works

Sequence matters more than speed. Water off, plumbing loose, drain freed from the P-trap — then the tub comes out. Pulling the tub first is how floors and traps get cracked, and RV LIFE’s bathtub replacement steps lead with the plumbing for exactly that reason.

1. Shut off the water supply, then remove the shower curtain or door assembly.
2. Take out the faucet, handles, and surround trim clips.
3. Disconnect the drain from the P-trap before the tub moves an inch.
4. Lift out the old tub and surround.
5. For a new pan in a fresh opening, trace the outline, check the space below the drain is clear, drill a pilot hole, and cut a 3″ circular hole in the flooring — the size Van Life Outfitters’ manual specifies.
6. Apply silicone adhesive, set the pan, and reinstall the drain fixture.
7. Reconnect drain and supply lines, then reinstall the faucet and surround.
8. Seal every seam with 100% silicone bath sealant, and let it cure before anyone showers.

One detail that catches people late: RV shower and tub faucets mount on 4″ on-center, two-hole spacing, so a replacement must match those holes or the wall gets patched.

Why Do RV Tub-To-Shower Conversions Fail?

Nearly every failure traces back to a skipped step, not a bad part. Five mistakes show up again and again, each cheap to avoid.

• Cutting before checking. A 3″ drain hole that lands on a frame rail is a ruined floor.
• Pulling the tub with the drain attached. The P-trap cracks, and now you’re fixing plumbing too.
• Ordering by eye. A 40″ pan won’t squeeze into a 36″ opening, and a right-hand drain won’t swap into a left-hand hole.
• Skipping the sealant. Unsilicone seams leak behind the surround where damage builds unseen.
• Showering too soon. Wet seams before the silicone cures pull apart.

Anything short of an exact match means trimming and refitting.

Measure the opening, order to the drain side, and give the silicone its full cure. Those three habits separate a shower that lasts from one you tear out twice.