Did the instructions call for a base to be installed under the tub?

Every tub or shower pan I installed needed a base(mortar or similar substance) applied before setting the tub/pan.

What HandyMac said.

I recently worked in a home where the plumber neglected to provide the proper base under the tub as HandyMac refers to. It had to be removed and reinstalled. It seems odd that your entire job would be completed without someone being aware of that mistake ... ?

What is the tub made out of?

Yes, it is an acrylic tub, purchased in 2014, installed 2015. When I purchased this tub, it was a new model for Kohler, one of the first to have a 16" depth. My Kohler distributor is checking with their Kohler rep because Kohler customer service has reduced hours between Christmas and New Year's. I did not hear back today, so perhaps the distributor is on reduced hours or holiday as well. I have also contacted my contractor, and my architect. This is my second major renovation of a 25 year old home, and this time I chose to hire first an architect and to use the AIA contract. I am very glad I did! It's a bit unusual for the owner to purchase the fixtures, but I was able to purchase at a greater discount through my architect (40 percent, not 25 percent), paying for her services. Paula Morris, Morris Architects, Gaithersburg, Maryland -- and Gabriel Ali, Manager, Thomas Somerville, Falls Church, Virginia -- highest recommendations.

Yes, I am concerned that the tub was not set correctly, however, the question is what is the best way to remove the tub and reinstall -- there are two of them. The tub in the basement hall bath is the same tub, installed by the same contractor and sub-contractor. Both are still under the one year contractor warranty.

To give you an answer you would need to tell us the model number of the tub. There are many kinds of acrylic tubs. Is it in an alcove? Does it have a removable apron panel? Perhaps it is possible to open up a side or rear wall from another room and add support. Removing the tub will disturb the wall cladding and plumbing.

Thanks to all the Houzzers who have responded to my query -- To answer JDS, yes, the tubs were both installed in alcoves, and the panel is not removable -- the tub and front panel are all one piece of acrylic. The tub drains on the right side, and on the other side of this plumbing wall (tub shower) is the master bath toilet closet -- it would not be as easy to work from this right side of the tub as it would be from the left side which is a bedroom wall without plumbing. The back wall is the exterior brick wall of the house -- also not a good choice for removal. I will post the Kohler number, but i believe it is still the only "Archer" Kohler tub sized 30x60" and up with a 16" depth from overflow to the bottom of the tub. The entire tub is about 21-22" high -- the basic Kohler tub has only 8" from the overflow to the bottom of the tub and is about 15-16" tall. The wholesale price is about $1000, and the MSRP about $1500.

Your questions require me to reconsider the fact that the Durock for the plumbing wall in this one tub has been removed not once but four times -- I believe it is possible that this vibration (screwing, unscrewing with automatic drills) may have loosened the joints in the plumbing -- but the question of whether there is water under the tub will be answered once the bottom of the tub is exposed. However, so far, we have not seen water on the ceiling below the tub. But with the pink insulation for sound, a lot of water could be absorbed, evaporated, absorbed, and so forth before reaching and damaging the drywall in the ceiling below such that a drywall joint would bubble.

I am really grateful for the information that this is a problem that can be resolved, and I am confident that our builder will honor his warranty -- and I will report back about what happened and what steps could have been taken in the construction to avoid this issue. Thanks!

We installed a very similar tub quite a few years back. Months later the HO complained of creeking noises. Since the area had a full tile surround, we elected to use spray foam to fully support the tub and glue it to the subfloor. After filling the tub with water to provide even weight distribution without scratching, we drilled small holes from below, through the plywood. Then sent the hose from the foam-inna-can through the holes to give even dispersion. We purposefully used the foam in the BLUE cans as that is very dense and doesn't push hard on the opposing surfaces. After the foam cured all the noises went away. That was 5 or 6 years ago.