Standard built-in tubs go on top of the subfloor, not on the tile, so you should not need to worry about what is under the tub. I assume vinyl tile would be a good water-resistant choice for around the tub, but I would check with the manufacturer or a sales rep at the store.

Bruce

Thanks, Bruce in NOVA! (we are in Winchester, BTW) So this will not be a standard built in but it will be a freestanding soaking tub. Is that also installed on the subfloor?

Is this tub on legs, or does it sit with a base going all the way to the floor, like this one?

Yes like that one.

Your issue isn't so much that the vinyl plank will be damaged, it is that it will likely let water through to the subfloor, even if it is installed tightly. You can waterproof the subfloor with a sheet membrane or liquid membrane like Redgard, but if water gets under there even if it doesn't damage the wood you can get moldy conditions in between the subfloor and plank.

There are some products that are made for bathrooms, but honestly if you want a warmer floor I'd consider sticking with porcelain tile with either a radiant heat system or just adding some insulation under the floor. Is your floor over an unheated basement or crawlspace? Some 2" eps insulation cut to size and foamed in under the subfloor between joists can do a lot to warm up a bathroom floor, and porcelain will always be way more durable in a wet space.

I would also look at the INSTALLATION requirement for the stand-alone soaker tub. Some of these tubs are very LIGHT. They can be moved/pushed around by a single individual. That means there are some installation requirements that need the tubs to be SECURED to the subfloor. This can muck-up a flooring installation decision.

Before you decide on your floor, you will need to decide on the TUB. It is the thing that will dictate everything else. It will be the star of the show. Figure that one out FIRST...and then make decisions AROUND the Diva.

Floating floors are installed around permanent obstacles, not under them. You would have a seam at the tub floor interface filled with caulk as your "waterproofing" to rely on for preventing slopped water from going down through your subfloor. The same for the pipe penetrations. Plus it's about twice as expensive a choice, and doesn't belong with a vinyl floor.

A freestanding tub is never a very good choice for someone concerned about waterproofing or water damage. Built in tubs were developed for a reason.

This just isn't true

Read the fine print, waterproof vs. water resistant. Big diff to the insurance agent.

Wouldn’t using a glue down vinyl plank solve the issue ? I was told the only true waterproof would be the glue down install?