Question: Hi Robert. We are in the midst of doing a bathroom remodel where currently there are fiberglass walls surrounding a cast iron tub. First question is, can we go to a new metal tub instead of the cast iron tub, and what is the difference?
We performed demo ourselves and, upon removing the existing tub, found a hole in the concrete around the plumbing that was about 8 inches deep and approximately 18 inches across. The concrete was collapsed, creating this cavity. Can you tell me what could have caused this?
Lastly, we would like to use a 6-inch by 3-foot-long tile on the walls surrounding the tub. Is it possible to use this size in that location?
– Dani T.
Answer: Dani, regarding the tub materials, the difference is durability and weight. Cast iron is virtually indestructible but extremely heavy and difficult to maneuver. The metal tub, in most cases, is sufficient and durable. You do need to exercise some caution but it is much lighter and easier to install than the cast iron. It’s likely more inexpensive, also.
The cavity in the concrete is likely caused by a slow leak, undetectable from the home because you are on grade. This means that the water went down into the ground vs. into the home, so over time it eventually eroded this area and allowed the concrete to collapse. It’s the most likely scenario, given no other visual issues that you’ve mentioned.
To resolve this, first ensure that the plumbing opening of your new tub matches up with the existing plumbing lines. Oftentimes they won’t, so at this point and in that situation, you will have to adjust the plumbing to fit the new tub. Once that is done, you’ll test the new plumbing before closing up this area and be sure it is sound, with no leaks.
Next, use plaster wash sand, which can be purchased at a big box store, and compact it to the best of your ability. Cover it with a bit of concrete over the top, making sure you keep the surface level with the existing concrete. You don’t want to end with a high spot there, so just use caution and keep it smooth. The ultimate finished look won’t matter, so don’t worry about that.
For the tile, I’d like to defer that question to the tile installer. Use a licensed and insured installer, and have them see what you’d like to use. They will inform you of the potential success or problems with what product you are wanting to use, and help you find something similar and more suitable for the application, if necessary. Don’t skimp on this part of the project – it’s the aesthetics and a quality job is important. Best of luck on your project.
Robert Lamoureux has more than 40 years of experience as a general contractor, with separate licenses in electrical and plumbing contracting. He owns IMS Construction Inc. in Valencia. His opinions are his own, not necessarily those of The Signal. Opinions expressed in this column are not meant to replace the recommendations of a qualified contractor after that contractor has made a thorough visual inspection. Email questions to Robert at [email protected].
