Help, at my parents rental property, I agreed to help them remodel. The vanity and toilet are out, as is the old fiberglass tub/shower. Today's question. The fiberglass tub has a lip on the fixture, side, and back edges that looks like a piece of 1 by 3 will support. Only the room side edge(where the curtin would hang, is to the ground. If I screw the 1 by 3 to the studs to level the tub, and then stand in it, it would go my feet-fiberglass-air gap-floor.
The air gap is approx 1 inch, with give and take. Is this a correct installation method, or do the new tubs need some bottom support? Please advise, or tell me if I need to rephrase the question. Thank You Chuck

All tubs, especially fiber glass need support inder them. The traditional mthod is to place a blob of modified thinset, baseball sized, every few inches on the floor in a checker board pattern, then set the tub. This will eliminate sqeeking and creeking. Also I am still not sure I can picture what you are saying, Can you reword or post a picture?

Agree with Ballengerb: put generous blob (1 to 2 bags) under the tub.

Post photo of the tub and surround...

Thank you for the responses, Ballengerb and Dolezal. Let me clarify my question and see if we are all on the same page. If you were to set the tub on a sheet of level plywood, the room side edge(where the curtin is) would be on the ground and the tub would be unlevel side to side. The back to drain slant is built in and constant. If I nail a 1 by 3 to the studs at 20 inchs off the deck on the three sides, the tub would sit level, but there would be an inch of airspace underneath the tub bottom.
Now, it is into this 1 inch airspace that I am to throw down baseball sized puttyballs, and let the tubs own weight mash them to level and support the bottom.
By thinset do you mean SACKRETTE with no rocks, about as firm as toothpaste? For a 1 inch gap, handball sized on a 6 inch grid pattern?
Thank You Chuck

Your on the right track. Do what you need to do to level tub, from front to back and from side to side. Best to set tub, level, make marks where lips are, remove tub, put down quickcrete, reinstall tub, set to marks on studs, secure with screws, and let set.

You added two word that both need to be removed from how you picture this. Not putty, not SACKRETTE, I said modified thinset. Modified thinset is a thinset plasticized with polymer. Comes in a bucket in the ceramic tile aisle of the store. Yes this is what fills that void, you have an inch and the baseball sized glob is about 3" so it gets squeezed and the hardens.

I'm looking for a video which would show the installation of a 3 piece tub/shower in an existing home.

I,m looking for a video which would show the installation of a 3 piece tub/shower in an existing home.

There are many instructional videos on YouTube. I am enclosing one of them. See if that helps...

YouTube - Swanstone -- How to Install Swan Fiberglass Tub Walls (http://www.youtube.com/watch?v=JQdKfEBfdhE)

Chasjmeier...

You can also use structolite as a bedding substrate for most installations (do not use with an americast tub)... see picture. This is usually sold at a home supply store and can be mixed to the thickness of peanut butter or so...

Dry fit tub so that you can mark out level and plumb and then measure how thick you need to pour the structolite... then add an inch... ;) Then you can pour the structolite to the FOOTPRINT of the tub... set tub, screw/nail the flange, plumb all up and let dry 24 hours. I like this material as it makes for a solid bottom over the entire bottom of the tub.

Modified thinset is also good, but usually expensive compared to a $10.00 bag of structolite.

Let me know if you want more info. On this...

MARK

Mark we each seem to have our own favorite for setting the pan. I agree that modified thinset costs more but only if you buy a 35 lbs tub for $44. I can set a pan with a 19=0 lbs tub which runs about the same as structolite. I use modified thinset primarily because I am frequently the guy doing the Hardiebacker sub floor and tiling. I can use the same stuff on all three apps, so its just a matter of convenience for me. Have a good one.