You might try a good 100% silicone caulk. But even that's going to be a temporary fix until you can afford to replace the base. Just make sure you let it dry out for a day or two to make sure you get a good bond, and watch for leaks immediately after to make sure you got a good seal. You alwo want to force the caulking into the crack and really try and fill it well. You'll want to have a rag with either mineral spirits or denatured alcohol to clean it afterward. You also might want to tape it off prior to doing this so there's not as much of a mess to clean.

Thanks for the suggestion, but *can* the base be replaced without replacing the whole shower? We wouldn't mind so much replacing just the pan, but don't want to replace the entire shower again. The crack is so narrow, I'm not sure if the caulk will really get down in it very well. I'll call the company that put it in tomorrow and see what they say, but I just wondered if anyone on here had experience with this type of thing.

I definitely think you should call the company and hopefully they can repair it with something better than caulk. I know corian can be repaired and cultured marble is essentially a solid surface as well. Maybe they can fill it with more cultured marble stuff and reapply the gelcoat on top to make a better seal. I hope so! Let us know what you find out.

I'd be curious what caused it to "pop" in the first place.

I talked with the installer and he says there is nothing we can do but replace the entire shower. I asked him why it would have cracked and he suggested house settling and said he had never heard of one cracking like that. My research suggests possibly thermal shock. The shower is over a crawl space and I just discovered that DH never put the insulation back after the leak problem. It cracked right where the water was hitting it. Although why it wouldn't have already cracked I don't know, since it has been much colder before.

If your house is more than a year old, it's done all the settling it's GOING to do. The only movement it'll experience now is the normal expansion and contraction with the seasons, and if that's what did it, I question the method of installation. Something was done wrong.

That's what I would have thought too with regard to settling. And there hasn't been any other evidence of settling anywhere else in the house. I'm still researching for any other options. Called another guy who said the same thing with regard to repairing it - he jokingly suggested maybe we had a very large ghost taking showers in our house.

Same thing happened to my cultured marble shower pan. A loud pop and then thin cracks extending from both sides of the drain hole. The original installer told me the same thing. He'd never seen this happen before and that I'd need to replace the whole shower because the wall panels sit on the pan top edges. When I examine the drain from underneath (from the crawl space under the house), I see that a 2x10 joist runs very close to the drain hole, close enough that the 3" plastic drain pipe is off vertical by 10-15 degrees. The pipe was obviously forced into position before the compression ring was secured. My theory is that this arrangement put great pressure on the floor pan, with the pan floor on one side of the drain hole being forced upward and the pan floor on the other side of the drain hole being forced downward. After 17 years of pressure, the floor finally gave way. My conclusion is that this was a serious plumbing error and I'm in the process of making my case with the plumbing outfit that did the work. They should have cut out a section of the 2x10 joist, thus allowing the drain pipe to be installed vertically, and then installing headers against the two cut ends of the joist. Seems to me the plumber is liable for the damage and the replacement of the entire shower.