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How to Install a Bathtub Insert

Bathtub inserts, also known as bathtub liners, offer an affordable way to update outdated bathtubs. Inserts fit over an existing tub and come in a variety of colors. They do away with the tough job of tearing out an old tub. In addition to saving time, the steps for how to install a bathtub insert are manageable for the average do-it-yourselfer. Here, the bath experts at PJ Fitzpatrick walk you through the steps.

How to Install a Bathtub Insert

  1. Clean the existing bathtub surface thoroughly to ensure that the adhesive can make a lasting bond. Use denatured alcohol because it will remove soap buildup.
  2. Remove all surface objects from your existing bathtub, like adhesive nonslip strips.
  3. Take off all fixture hardware, like drain covers, faucet knobs, and shower head. Use an adjustable wrench as needed to loosen the hardware.
  4. Do a dry fit of the bathtub insert before applying any adhesive. Trim the insert edges with a utility knife as necessary to create a perfect fit.
  5. Set aside the insert.
  6. Spread butyl primer along the edges of the existing bathtub where it will connect with the insert. Allow primer to dry completely according to product directions.
  7. Apply butyl tape over the primed edges. Keep the tape 3/4 inch from the wall.
  8. With the caulking gun, apply silicone adhesive along the edges between the wall and the butyl tape.
  9. Attach more butyl tape to bottom of the bathtub insert. Cover the bottom surface with tape completely making sure not leave any gaps.
  10. Spread a layer of silicone adhesive over all existing bathtub surfaces, including the sides, rail, and outside skirt. Make sure to apply adhesive thoroughly around the drain and overflow.
  11. Press insert into place over the old bathtub. Apply pressure across all surfaces to ensure contact with the adhesive.
  12. Replace the faucet hardware.

Tools & Materials

This method for how to install a bathtub insert requires common household tools. If you don't already have the necessary tools, they’re easy to find and are fairly affordable.
  • Denatured alcohol
  • Butyl primer
  • Butyl tape
  • Utility knife
  • Caulking gun
  • Silicone adhesive
  • Silicone caulk
  • Adjustable wrench

Consider a Bathtub Replacement

Bathtub inserts are generally considered less desirable than replacing a bathtub. The team at PJ Fitzpatrick specializes in bathtub replacements and tub to shower conversions. Ask us for an estimate to compare costs and quality before you take the time to learn how to install a bathtub insert.

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