We hired a contractor to completely gut our bathroom and install a tub/shower combo. When showering, if any water splashes outside the tub, water will drip from a light fixture in the floor below.

My contractor claims this is expected - the "wet" area of the tub is waterproofed (he used hardibacker), while everything outside of the tub is not waterproofed.

Does this sound right? We're not splashing a huge amount of water outside of the tub (less than a glassful). I would've thought the water would pool on the tile and eventually dry up, not leak into the light fixture below. My contractor siliconed around the outside of the tub/base moulding, but it hasn't helped.

Any recommendations? Should have my contractor waterproofed outside of the tub as well (i.e. the tile floor outside of the tub)? Or would more silicone/caulk around the tub/moulding help (he didn't silicone the bottom of the base moulding, only the sides).

We will of course try not to splash water outside of the tub, but we have guests and kids that will inevitably forget to put the shower liner on the inside of the tub and/or will splash water outside the tub.