Why does the mastic on my shower floor not dry?

Over a concrete base and then sealed with tile, the water has a difficult time evaporating from the mastic. What did you use, most people use thinset in a shower? If you used Acrylpro, it is not approved for that purpose.

How long did you let it set. What did you use?

Bathrooms with showers or tubs, are steamy, the steam is basically water. Mastic needs a dry room to set. If you set the tiles, used the mastic, and then didn't give it time to set, then that's why it's still gooey, and not set.

How long did you leave it to set?

Bathroom renos are hard. If you're setting tile, grouting, and all that it takes times, sometimes weeks, depending on what you use, before you can use the bathroom again. It's not just setting the tiles and then showering or bathing, or even using the toilet or sink. You need to give it time to set, and the more enclosed it is, the more time it needs. No window, no air flow, means a week or more to let it set and harden before you use that bathroom again.

Add: and then there's grouting, and sealing the grout. It's not a quick reno. It's why people with only one bathroom/tub/shower, rarely renovate, because there's no way to use the bathroom while you're renovating, for weeks on end if you do it right.

Gail,

You said you used mastic, if so, you need to remove the tiles and clean all that stuff off. Depending on any other mistakes, I might suggest more removal. Can you tell us how this project was done and especially tell us specifically what materials were used.

Jaz