How can I determine if hairline cracks in fiberglass and cast iron tubs are leaking underneath without causing damage, and is silicone a viable temporary fix?
Asked by Emilio Ocampo 
3 months ago
Last Updated: September 25, 2024
I noticed a hairline crack in the fiberglass tub of the house I clean, and my roommate also has a similar crack in his cast iron tub. The one in the fiberglass tub is about 5 inches long and in the middle, while the one in the cast iron tub is also 5 inches long and comes out from the drain. I’m concerned about potential leaks underneath the tubs – is there a way to check without causing a big mess? The homeowners are thinking of using silicone and sandpaper to temporarily fix the cracks, but I’m not sure if that will work. Has anyone dealt with something like this before?
Yeah, it could hold up temporarily but it’s best to start thinking about getting a replacement soon. Take a look downstairs (if you can) to check for any leaks.
It might do the trick for a couple of hours. I remember mentioning to a slumlord in my neighborhood that he should get a new tub. The one I fixed with JB weld has been holding up for 6 years (mostly), but it’s not the prettiest sight and occasionally leaks when the JB weld gives out.
For a hairline crack, it could be that only the enamel is cracked and there’s no structural damage underneath.
A repair kit for fiberglass tubs can yield impressive results when applied correctly.
Take a peek behind the wall where the faucet is located. There might be a closet with a panel for pipe access. Look under the tub as well.
Both leaks should be repaired, whether they are currently leaking or not, to prevent further damage. Kits are available for both types of repairs.