Call a fiberglass repairman.A local supply house will most likely have the number of someone they use.Alot of cracks are caused by stress due to lack of support.A good repairman should be able to spot problems which can cause this crack to recur.
Hello, The problem you desrcibe is common in older tub/shower units. It can be repaired most times in one day and ready to use the same day. You do need to find out to out to what extent the supports are giving out (If at all) the way to do this is stand in the unit and check to see if the area is solid or spongy. if its spongy the supports are going, if not, it may just be a simple crack. In either case you need to call a tub repairman, this is just so you know what you may be dealing with before the call is made. Good luck…glas-tech.com