Vinyl plank floor?

[daddo]

Vinyl plank.

Under the toilet- yes. If you ever replace the toilet, you'll be replacing the floor as well if you don't, and it will never look right.

Under the shower- no.

[mil]

floating floors under the toilet are not a good idea

[Cooler]

On the subject of vinyl plank flooring (LVT), can I install it directly over 12" x 12" tile?  The ground line is lower than the tile surface and is fairly wide.  The Lowes' LVT has a "built-in" underlayment.

Will the grout lines eventually telegraph through the LVT?  Removing the old tile and grinding down the old mastic is going to be a lot of work.  I would like to avoid that.

[R Clark]

Do the manufacturer's instruction contain info about smoothing the underlying surface?  I would follow those first.

Some of the manufacturer's web sites have FAQ pages where questions like this are often answered.

However, I think those tile grout lines will telegraph sooner or later.  I'd level them.

[MstrCarpenter]

If your tiles are basically intact and solid, I would set new tiles directly on top of them. Being fully competent with tile, laminate and LVT I would guess tile vs. LVT to be about the same in labor and material costs. (I compare laminate with carpet.)

[Cooler]

If your tiles are basically intact and solid, I would set new tiles directly on top of them. Being fully competent with tile, laminate and LVT I would guess tile vs. LVT to be about the same in labor and material costs. (I compare laminate with carpet.)

You would put mastic over the old tile and lay new tile on top of it?  Will that provide enough adhesion?

Would self-leveling concrete work for filling the grout lines?  Or should I simply add more grout and use a putty knife to level the grout lines?

[EightFingers]

If you lay new stuff over old stuff, how do you check the condition of the subfloor?

[Cooler]

If you lay new stuff over old stuff, how do you check the condition of the subfloor?

With LV planks, I was not worried about that.

They make 1/4" thick underlayment (foam panels) for laminate flooring.  Can I put that under LVT?

[Roly]

With LV planks, I was not worried about that.

They make 1/4" thick underlayment (foam panels) for laminate flooring.  Can I put that under LVT?

Contact your flooring manufacturer as they will be guaranteeing the flooring.  They will say what they want done for their flooring when placed over tile.  Without any direction from them I would use thinset to level out the grout lines . Roly

[MstrCarpenter]

You would put mastic over the old tile and lay new tile on top of it?  Will that provide enough adhesion?

Would self-leveling concrete work for filling the grout lines?  Or should I simply add more grout and use a putty knife to level the grout lines?

Yes, one of the modified thin-sets following manufacture's recommendations for that application. Even if they don't require it, I roughen the face with a diamond cup wheel. You don't have to grind off all the glaze, so use just enough water to quell the dust, then wash with TSP.  Whoever guts the bath next time will be removing both layers of tile at once. They won't come apart. If there are no existing cracked tiles, then the sub-floor should be o.k.. I check for un-bonded tiles by tapping with a hammer or dragging a chain around the floor.

If you decide to fill grout lines, I suggest Rapid-Set Cement-All. Mix to a consistency of pancake batter with a power drill and appropriate sized mixer, pour it from a paper cup where needed. You can scrape it flush when it starts to set, but before it hardens. This time frame is only a few minutes, so work fast or do small batches. It's ready for foot traffic before you can finish cleaning your tools.

You do not use foam underlayment for laminate floors under L.V.T.. L.V.T needs a solid flat surface. Any bumps will show as you wear through the "wear layer" and color sheet revealing the white color backer sheet.

Floor leveler (i.e. Level Best and Level-lastic) will not stick to the face of glazed tiles.

It sounds like your L.V.T. is a peel-and-stick ship-lap variety. The adhesive is pretty good, but will not hold up with standing water.

Hope this information helps.