As I stated in other posts... I've installed ALOT of tubs and have never put mortar under the tubs and have never seen mortar put under tubs. I have another tub/shower swap out to do next week. The customer weighs 345# and I want to make sure he has plenty of support. BennyBaby is suggesting structo-lite or some similar item. Just wondering what you guys suggest. Will just regular old cement mortar work or is there a specific type of mortar I need to consider? I assume that I can just cover the area with plastic and dump about a 1-2" layer of mortar down and plop the tub right there then hook it all up as usual...and add on $200 for my grief.