QUESTION

Crack in Tub to Wall Sealant Joint - My wife & I hired a very reputable company to do a full bathroom remodel, which was just completed about a month ago. The tiles on the wall look great but a problem that we are now seeing is that there is a very noticeable larger than hairline crack running through the middle of the sealant around the bathtub where it meets the wall. The first time we saw this was when the tub was filled with water. We then called back the grouting person who redid the job and this time with the tub full - we also left the tub filled for a few days after that to let the sealant properly dry. Nonetheless, after a few days of use, the cracks reappeared - although they are mostly visible only when the tub is full or when a person is standing or sitting in it.

Our new tub is a standard acrylic (fiberglass?) model and the contractor is telling us that the give we are seeing is to be expected and we will need to do regular regrouting every few months. We have asked around about the problem and are receiving conflicting information ranging from "it's normal with this type of tub" to "it's a structural problem with how the tub is seated". What we would really like is for an unbiased qualified inspector to come in and take a look and give us a proper diagnosis. We live in the Pasadena/Los Angeles, California area and we were wondering if your organization can either offer or recommend a service that might be able to help us out with arranging an inspection.

Thanks very much and any further info is greatly appreciated,

ANSWER

ANSWER - It is not normal for that joint between the tub and the wall to crack and it should not have to be redone on a regular basis.  There could be a few things wrong.

First is the installer probably used the wrong type of sealant.  Commonly installers use a latex based sealant that is easy for them to use and will not last.  The manufacturer of these types of latex or acrylic sealants will not warrant them for lasting.  The proper type of sealant that is required per the tile industry standards is one that meets ASTM C920, which is normally a 100% silicone structural sealant or a urethane sealant.  These types of sealants will last many years and the manufacturers warrant them.

Second is that the joint width of this transition joint should be at least 1/8” wide and ¼” deep so the sealant can adequately fill the joint and so there is enough sealant to allow it to elongate with the movement of the joint.  There needs to be a proper foam polyethylene bond breaker backer rod embedded into the joint before the sealant so there is only two point contact to further allow the sealant to maximize its elongation during movements.

Third is that the tub needs to be properly installed and supported so that it doesn’t move excessively.

We can and would be happy to perform an inspection with one of our local inspectors, but it might be cost prohibitive for this type of a problem.  Please go to our website at www.CTaSC.com to make a request for service for a cost estimate to perform an inspection.