Done it in the past. i used plaster of paris because of the dry time and i had some lying around. This time i want to make it more a permanent setup. In my experience with actually setting tile floors sanded grout is always preferd over unsanded due to the amount of strength it provides compared to the unsanded. Why is unsanded recomended over sanded grout? can anyone explain why people do not use sanded? is it because of the paint not being able to stick well?