Replacing bathroom floor

[finpend]

I cannot locate anything close to this so I have started this thread, hoping for some good, useful instructions. Our bathroom fixtures are coming out and new being installed. When I removed our cast tub, I find it was setting on the sub-floor (plywood). I don't feel this was unusual 50 years ago, but want to do the right thing now. There also is no underlayment under the sheet vinyl, which we will also be replacing. My main question now is, when I put down underlayment for the vinyl, should I go ahead and place it under the new cast tub, or should I wait until the new tub is in place and run the underlayment up to the apron? This will be a standard 5' drop-in tub. If I should put it under the tub area also, i.e., the whole floor, would I be better off putting the smaller pieces of underlayment under the tub or out in the open space of the room? Room size is roughly 5' x 10'. The tub and vanity are out already, but the commode is still in place. If I use 1/4" underlayment, do you foresee any problems with the toilet flange, after removing the toilet, without knowing beforehand how it looks? The additional 1/4" thickness will not adversely affect the door opening, but any thicker would. What is considered to be the product of choice for underlayment for sheet vinyl today? Thanks to all of you.

Fred

 

[Jadnashua]

No need to put anything else under the tub. Ideally, the toilet flange would be repositioned on top of the new floor, but they make extension rings to raise it which is easier.

Not sure what they are using for new vinal installations these days, but luan had been a common choice with all nail and seams filled to make a nice smooth surface.