How to Tell If My Tub Is Steel or Fiberglass?

Renovating a bathtub is a task that many homeowners choose to undertake on their own.

Determining your tub's material is the first step in renovating it.Determining your tub's material is the first step in renovating it.
Such DIY projects can save you the time it takes to search for a contractor, compare prices and wait until your chosen worker can perform the task. Tackling a project yourself saves money, because you won't be paying anyone for labor costs. Before you can remodel your tub, however, you have to know whether it is made of steel or fiberglass -- remodeling materials that work for one may damage the other beyond repair. There are a couple of ways to find out for sure.

Hold a refrigerator magnet next to the surface of the tub. Try to stick it onto the tub. If it sticks, the tub is made of steel, as steel is magnetic. If it does not stick, the tub is made of fiberglass, which is not magnetic.

Knock on the tub three or four times and listen to the sound. If it sounds hollow, it is made of steel; if it sounds dense, it is made of fiberglass

Observe the tub for any chips or deep scratches. If you find one, investigate the material you can see through the damage. If it is black and flat, the tub is made of steel. If the material is fibrous, it is made of fiberglass.

Things You Will Need

  • Refrigerator magnet


  • Never attempt to refinish or remodel a tub until you know the material used to make it. If in doubt, consult a professional.

About the Author

Samantha Volz has been involved in journalistic and informative writing for over eight years. She holds a bachelor's degree in English literature from Lycoming College, Williamsport, Pennsylvania, with a minor in European history. In college she was editor-in-chief of the student newspaper and completed a professional internship with the "Williamsport Sun-Gazette," serving as a full-time reporter. She resides in Horsham, Pennsylvania.