Americast Tub Question/Worries

I had an Americast Princeton tub put in back in late 03' in my soon to be rental condo property. I remember the tubs were kinda new at the time to me so I searched to see if mortar was needed or not underneath, I found nothing. So the plumber said to go with no mortar as he said installation specs called for none. I agreed even thought I felt iffy about it. I am pretty sure he used ledger board also.

Needless to say, I moved away to Hawaii, renting the place out to a couple with two young kids. I came back in 07', and with housing being the way it is now, instead of trying to hustle and buy a place, I moved right back into my old condo.

Here we are 7 whole years later and I still from time to time check the back access panel to ensure everything looks OK under the tub and its dry, etc. Everything looks OK and the tub seems very sturdy, I was 250lbs now 218lbs and my wife and I both use daily, etc. I clean with Soft Scrub, no worries. Looks as good as the day it was bought.

But I still think about should I have used the mortar? I read the forums here and it makes me even more uneasy about it. Maybe spray foam, I have access to slide something under it, but it doesn't seem like it flexes to me at all. Its very sturdy. The surrounding walls were cement floated and have ceramics all around.

Am I still worrying about nothing? I am still looking for a house (cant find anything but junk), but I do want to continue to rent this unit once I find something else.....

The Americancast doesn't need any other support.
It's a steel tub.

And American Standard does not recommend mortar the those tubs.

The install instruction state the use of mortar will CAUSE damage.
I don't know why, They never really said why.

The install instruction state the use of mortar will CAUSE damage. I don't know the reason, but the tub is stiff, doesn't need beefing up, and I think it needs to be able to "move" when necessary. There are three layers....the resin base, a very thin pressed steel liner, and the porcelain enamel layer. I think stiffing it up too much may not allow the necessary expansion/contraction of the various layers.

These Americast tubs appear to be very well-regarded on this and other forums, but as for me, I am totally unimpressed with them. I just pulled one out of my bathroom that was installed about 10 years ago right before I bought my house. I'm not a heavy guy and yet as long as I can remember the water has pooled slightly to the right of the drain. When I pulled it out, I saw why -- the resin had what I'd best describe as "fault lines" in it, there must have been 3 or 4 of them, each about 8" long, running the length of the tub. I wish I'd taken photos of them. The cracks went all the way through to the steel and allowed for deformation.

I am convinced that if the tub had been installed in mortar, this would not have happened. I will never use one of these again, despite their popularity.

I read somewhere the reason they say no mortar is that the curing of the mortar may cause the resin layers to delaminate from the metal layers. Not sure if its the heat during cure, if the mortar will dry out anything in the resin, etc.

I for one used a mortar layer under my Americast tub BUT I put 6 mil of plastic over the mortar bed before dropping the tub in. Time will tell if it ever causes an issue (only installed last year) but so far Im impressed with the tub. No creaking like its "cheap", and it doesnt take much to warm it up before taking a shower.....I have a cast iron tub in our other bathroom and its ALWAYS cold for the first 5 minutes of a shower (and considering I only take 10 minute showers, its not very relaxing!)

Ill probably replace that ci tub with an americast or acrylic unit (I dont want to go acrylic but the wife wants a deep soaking tub, and in the size we have there arent many non-acrylic options), plus its on the 2nd floor and I dont feel like lugging a ci tub up there

It is a steel tub, reinforced by the "americast" process. If you haven't had any problem in eight years, I would think it was time to move on and start worrying about something else.