What Type Of Bathtub Do I Have?

At Bath Crest of Colorado we can refinish almost any kind of commercial or residential bathtub. We can also convert nearly any type of bathtub to an accessible walk-in shower/tub.

Homeowners are often not sure what material their tub is made of (fiberglass, acrylic, cast iron, steel). Below we have provided some general descriptions so that you may find out what type of bathtub you have. We can help you identify your tub type and give you a free estimate. Contact us today to schedule.

Quick Bathtub Type Reference

  • Magnet Test

    Does a magnet stick to your bathtub? If so, your tub is likely cast iron or steel.

  • Tap Test

    Give the side of your tub a knock. Does it sound like plastic? If it sounds like plastic, your tub is likely fiberglass or acrylic. Hint, knock on a cast iron pan for reference.

  • Rust Test

    Does your bathtub have rust? If it does, you have a metal tub, you can rule out acrylic or fiberglass tubs.

  • Yellow Stain Test

    Is your bathtub discolored or does your bathtub have a yellow stain? Most likely an acrylic tub, although other tubs may be prone to stains and discoloration as well.

Enameled Steel

Steel tubs are stamped from a sheet of steel and then covered in a thin coat of porcelain enamel.

Older, worn tubs may have chips or rust. As far as metal tubs go, enameled steel tend to chip more easily than cast iron as it is a thinner layer of porcelain. While rust on your tub is unsightly, it is a helpful tool to identify your bathtub type.

Cast Iron

The way to determine if your bathtub is cast iron tub is that a reasonably strong magnet will stick to it.

If the side of your tub is accessible, give it a little push. If it doesn’t give at all, likely cast iron. A classic vintage cast iron tub shape is the clawfoot tub, which would allow access to the side of the tub.

Cast Iron tubs are also the heaviest of the group. If you have access to view the subfloor beneath the tub, look for extra joists or other signs of a reinforced floor.

enameled cast iron tub If you have a cast iron tub, don't be in a rush to get rid of it. Cast iron bathtubs are excellent tubs. We can fix most rust spots, chips etc. when we refinish your bathtub. Cast iron tubs have a lot of great qualities. Cast iron tubs are great insulators, they keep your bath warm longer. Think of some of the great enameled cookware on the market- Le Creuset, Lodge, Staub, all known for (among other things) their great insulating properties. Take a look at this 1940's era cast iron tub pictured here. We refinished this Denver area home cast iron bathtub. The homeowner loved the original tile on the floor as well as the tile surround. Refinishing the tub meant that the original tile was left in place; the tub looks like new with a clean refinished surface.


Does your bathtub have an unusual shape? Fiberglass is likely your tub. Fiberglass allows for complex tub shapes. Fiberglass tubs are typically formed by layering fiberglass into the tub mold (the shape of the tub). The layers of fiberglass are then coated in a resin.


Acrylic tubs usually start with a base of fiberglass; the fiberglass provides strength and durabilty. Atop the fiberglass is sheets of vacuum-formed acrylic.

Is your bathtub discolored or does your bathtub have a yellow stain? Staining is a characteristic of acrylic tubs, especially older bathtubs. The good news is we can fix your stained bathtub without removing it by refinishing your bathtub.