I have a shower stall with a cement-like slab base. The shower base is ancient and has developed some cracks. The top surface has some sort of sealant which has worn away, with the result that water can leak down into the slab.
I don't see water damage in the ceiling of the room below, but am worried nonetheless. I tried to re-seal the slab with some garage floor "epoxy" paint, but after 6 months that surface has bubbled and cracked. I'm not sure why it bubbled, as I did a pretty thorough job of roughing the surface for it to seal to. As the bubble was in the same place as the original crack, perhaps there is some relation?
Is there a better material to use to seal such a surface?