Most people have a general sense of what their bathtub is made of, but aren't entirely sure. It matters more than you might think, the material affects how the tub ages, how it sounds when you knock on it, how it feels underfoot, and what refinishing looks like for that specific tub.

Here's a practical guide to identifying the three most common bathtub materials found in Calgary and Alberta homes.

Cast Iron with Porcelain Enamel

Cast iron tubs are the oldest and most durable type. They were the standard in North American homes for much of the twentieth century and are still found in many older Calgary homes and heritage properties.

How to identify it: Cast iron tubs are very heavy, significantly heavier than any other tub type. If you knock on the side of the tub, it produces a dull, solid thud rather than a hollow sound. The surface is porcelain enamel, which is glass fused to the cast iron under heat, it's hard and glossy when new.

How they age: The porcelain enamel surface can chip (sometimes down to the cast iron beneath), develop crazing (fine surface cracks), or lose its gloss over decades of use. But the cast iron body itself is essentially indestructible.

For refinishing: Cast iron tubs are among the best candidates for refinishing. The porcelain enamel surface bonds well with professional refinishing coatings, and the underlying material is in excellent condition in the vast majority of old tubs. Many of the finest refinishing jobs we do are on cast iron tubs that are 50, 60, or more years old.

Fiberglass

Fiberglass tubs became common in new construction from the 1970s onward. They're lightweight, inexpensive to manufacture, and were a practical choice for builders.

How to identify it: Fiberglass tubs are lightweight and feel slightly flexible when you press firmly on the wall or floor. They produce a hollow sound when knocked. The surface has a slight texture and is less perfectly smooth than porcelain enamel. Over time, fiberglass surfaces tend to yellow, fade, and develop a dull, worn appearance.

How they age: Fiberglass ages more visibly than cast iron. The surface dulls and yellows with time, and is prone to scratches, chips, and stress cracks, particularly in the floor area, where the tub flexes slightly under weight.

For refinishing: Fiberglass tubs can be refinished. Chips and cracks are repaired before the coating is applied. One consideration with older fiberglass tubs that have yellowed significantly is that colour matching the finish to the original is more challenging, something our technicians will discuss with you honestly before the job.

Acrylic

Acrylic tubs are the most common type in homes built in recent decades. They look similar to fiberglass but are a different material, formed from sheets of acrylic plastic.

How to identify it: Acrylic tubs are also lightweight and produce a hollow sound when knocked, similar to fiberglass. The surface is slightly warmer to the touch than porcelain and tends to feel less perfectly rigid. Acrylic is available in a wider range of shapes and styles than cast iron.

How they age: Acrylic surfaces scratch relatively easily and can fade or dull over time. They're also prone to surface damage from abrasive cleaners, something that accelerates wear considerably.

For refinishing: Acrylic tubs can be refinished effectively. Surface damage is repaired and the coating bonds to the acrylic surface.

A Note on Cultured Marble and Steel

Cultured marble tubs, a cast polymer material with a smooth gel-coat surface, are less common but found in some Calgary homes. Steel tubs are similar in appearance to cast iron but lighter. Both can be refinished by Blackstone Tub Refinishers.

If you're not sure what type of tub you have, describe it to us when you call, or simply tell us the approximate age of the home and what the tub looks and sounds like. We've worked on every common tub type across southern Alberta for over 24 years and can usually tell you what you have from a brief description.