Hydrotherapy massage tub mounting

[Erby]

I looked under the tub surround while waiting for the tub to fill. I saw a bunch of hair bands along the back wall. Wondering how they got there I looked a little closer.

The tub stuck up above the tile surround by about 3/4" Three sides of the tub had this gap covered with wood cove trim. The back side, against the wall, was open and stuff had fallen under the tub.

Looking underneath the tub, I saw that the tub was sitting on 2" x 4" boards instead of a mortar bed as I usually see.

Don't the instructions for most such tubs call for a mortar bed?

After I found the 2" x 4" supports, I stepped in the tub and it flexed quite a bit.

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[Mike Lamb]

Don't the instructions for most such tubs call for a mortar bed?

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Wood can be used as long as the tub is level and supported from beneath. If it is flexing there will be a problem. Jacuzzi says mortar and foam can be used but wood can be used too.

[John Kogel]

They've glassed a sheet of OSB across the bottom of the tub and that is supposed to make it strong. A few years ago, I encountered a similar tub that had a hairline crack at the rim from the bottom sagging.

I would call it an amateur (and sloppy) installation. Easy to undo what's been done there, and that's the good part.

[Erby]

Couldn't see it that good, but it looked to me like that OSB was glassed onto the end of the tub to support the motor and pump, not extending all the way under the tub.

[kurt]

I know wood can work, but I'd never do it. The only way I've ever seen these tubs work is when they're set in a bedding compound.

[Mike Lamb]

Most of the time you can't see beneath so I step in the tub or shower stall. If it flexes I write it up that bad things just might happen. I didn't use to do this until it came back and bit me.

[John Kogel]

Right. I've come to the realization that plumbers don't read, even if they know how.

Often as not, the only thing supporting the floor of a fiberglass shower is the drain pipe.

[Scottpat]

That tub has little feet/stubs on the bottom that allow it to sit on the ground/wood or whatever. No mortar bed is needed with that type.

[Denray]

I'll usually step in the tub or shower before filling with water. That way my wet boots aren't tracking thru the house.

I've stepped in tiled showers and felt the grout cracking below. They're usually the showers that don't look like they are being used.