Hi folks. We're having difficulty with a tub install and could use some input.
We purchased an MTI baths Andrea 11 airtub and intend on mounting it into a frame with deck material above the flange of the tub. The frame has been built and the tub is perfectly level when sitting on the frame.
However, the tub sits on 2-3 inches of foam under which is a thin sheet (maybe 3/8 to 1/2 inch) of plywood/particle board. The whole system is called a "pre-leveled frame" although technically we build the frame. The undersurface of the plywood rests about 1/8-3/8 inch off the concrete slab, so there is a gap under the entire pre-leveled frame. Basically, the tub is only supported by the flange sitting on the wood frame built by the carpenter.
Our contractor originally wanted to use expandable foam to fill the gap between the bottom of the plywood and the concrete slab, but from what I've gathered from this site, that would not be appropriate. The manufacturer (with whom we spoke on the phone) has stated that this might be ok, although there is a risk that it will cause the tub to rise unevenly and no longer be level. We are pushing for mortar, but we we fear that it won't set thin enough under the thinnest gaps. My contractor also mentioned plaster, but the installation book clearly states plaster is not to be used. Our building superintendent has recommended strategic placement of constructive adhesive. We've even discussed "shingle shims" AND spray foam.
This is all very confusing for me and our contractor. The plywood is intended to sit right on the floor (per the install manual), but we can tell from the gaps that if it were to sit right on the floor, the tub would no longer be level.
Any thoughts? We're kind of desperate here.
Any advice you can give would be most appreciated.
Thanks!
We purchased an MTI baths Andrea 11 airtub and intend on mounting it into a frame with deck material above the flange of the tub. The frame has been built and the tub is perfectly level when sitting on the frame.
However, the tub sits on 2-3 inches of foam under which is a thin sheet (maybe 3/8 to 1/2 inch) of plywood/particle board. The whole system is called a "pre-leveled frame" although technically we build the frame. The undersurface of the plywood rests about 1/8-3/8 inch off the concrete slab, so there is a gap under the entire pre-leveled frame. Basically, the tub is only supported by the flange sitting on the wood frame built by the carpenter.
Our contractor originally wanted to use expandable foam to fill the gap between the bottom of the plywood and the concrete slab, but from what I've gathered from this site, that would not be appropriate. The manufacturer (with whom we spoke on the phone) has stated that this might be ok, although there is a risk that it will cause the tub to rise unevenly and no longer be level. We are pushing for mortar, but we we fear that it won't set thin enough under the thinnest gaps. My contractor also mentioned plaster, but the installation book clearly states plaster is not to be used. Our building superintendent has recommended strategic placement of constructive adhesive. We've even discussed "shingle shims" AND spray foam.
This is all very confusing for me and our contractor. The plywood is intended to sit right on the floor (per the install manual), but we can tell from the gaps that if it were to sit right on the floor, the tub would no longer be level.
Any thoughts? We're kind of desperate here.
Any advice you can give would be most appreciated.
Thanks!
