How to remove this floor?

[Sibley]

This is dumb, but I'm stuck. My bathroom is 4x6 ft. The floor is stick on tile on top of 1/4 inch plywood on top of something. Somewhere down there is subfloor. I need to get down to subfloor. How do I remove the plywood without a ton of collateral damage? I don't see any fasteners where the tile has come up. But I also have no clue how this is typically installed, so maybe I'm just missing them?

[NaN]

This is definitely a hard part of demolition. Is there any way to see how the 1/4" plywood underlayment is attached? If it is bonded or screwed then that's a problem. If nailed, with a few strategic pulls on a crowbar then it is possible it will pop right up, with tile and all. You can also with a good 3" wide solid chisel start cutting away the tile.

Sorry @Sibley , I wish I had a better answer. Maybe others might

[sonofsven]

This is dumb, but I'm stuck. My bathroom is 4x6 ft. The floor is stick on tile on top of 1/4 inch plywood on top of something. Somewhere down there is subfloor. I need to get down to subfloor. How do I remove the plywood without a ton of collateral damage? I don't see any fasteners where the tile has come up. But I also have no clue how this is typically installed, so maybe I'm just missing them?

I use a skil saw (circulating saw) with the blade set to around 3/8" and make a few cuts, then you can start prying it out, with more cuts as needed.
It's usually nailed every 4-6" with small ring shank nails

[nereo]

This is dumb, but I'm stuck. My bathroom is 4x6 ft. The floor is stick on tile on top of 1/4 inch plywood on top of something. Somewhere down there is subfloor. I need to get down to subfloor. How do I remove the plywood without a ton of collateral damage? I don't see any fasteners where the tile has come up. But I also have no clue how this is typically installed, so maybe I'm just missing them?

Ugh - yeah this can just be a lot of work (but ultimately worth it if laying down new flooring).

My first question is whether you actually *need* to get down to the subfloor - sometimes you can just install over what’s existing (e.g. LVP).  But when given the option and when I have the time I always favor going back to the subfloor.  Whether it’s worth the time depends on what you are going to lay down, why you need to get under in the first place, and how uniform the existing floor is.

As sonofsven said, circular saw set to the depth of the glue-on + 1/4” ply (so between 3/8” and 1/2”).  Cut a grid that forms 6” to 8” squares, then use a pry bar and hammer to pull them up.  Occasionally you’ll be “rewarded” by finding there’s yet another layer underneath you didn’t even know about (when I demoed our 120 year old kitchen floor I found three layers of glued-down linoleum before I ever got to the subfloor.

The tile is (as you said) stuck to the 1/4” ply with adhesive that can be really hard to remove.  The 1/4” plywood might be attached using screws, or adhesive (e.g. Liquid Nails) or if you are really lucky - both.  Just take it a few square inches at a time.  Thankfully you only have 24 sqft, though this project will make it feel a lot bigger for a while.

[BudgetSlasher]

Are stick on tiles ceramic tiles installed with adhesive or vinyl stick down tiles?

Personally I've found brute force to work. I would get a long prybar/scraper and get in under the 1/4 ply and pry it up in chunks. Then come back and remove any fasteners that remain. I did in the last bathroom I worked on with ceramic tile thinset to 1/2 cement board that was screwed to the sub-floor.

If it is glue to the underlying levels that is going to be a PITA to remove. I might consider whether I could layer on top of what already exists at that point.

[Sibley]

Stick on vinyl tiles, and they aren't necessarily hard to get up. Some of them just pop up. I haven't deliberately tried to remove all of them though, so it's possible the rest are a pita. Thus far I see no evidence of how the plywood is attached. About 1/3 of the tiles have come up so far.

Yes, I have to get to subfloor. The existing floor is too high, I can't put the new tile on top. There's also water damage around the toilet, so I have to evaluate and repair it as necessary. I'm hoping it's just the plywood that's bad. Plus, the plywood smells (parents, your little boys are not sanitary in the bathroom, it's your job to teach them better and clean up after them).

New floor will be ceramic tile. I will probably be doing it myself because I can't find someone willing to do a small job who will also do a good job.

I'm prepared for surprise floors under the plywood, I think there must be something there but can't tell. I know there's multiple floors in the kitchen and the other bathroom, no reason to think this one isn't similar. Yes, I'll be wearing proper PPE when I do this.

I will ask dad if his saw can be set to different depths, it's quite old so don't know. If not, I'll borrow one from someone. There's no gap sufficient for me to go from the edge with a prybar without also damaging the wall quite a bit, but I am confident that I can manage if I make cuts in the floor.

Thanks all.

[Frankies Girl]

Be careful regarding cutting into an unknown floor. If your tile/vinyl flooring is older than 30ish years, you may have old style asbestos in there, and want to remove it carefully.

https://inspectapedia.com/hazmat/DIY-Asbestos-Floor-Test.php

[Sibley]

Update. I finally removed the floor today. All layers down to the floor boards had water damage, around the toilet flange we were removing plywood in pieces. The floor boards got some moisture but are solid, but I will spray with with mold killer just in case.

Vinyl stick on tile on top of luan plywood, on top of 3/4 inch plywood. About a million nails and a good smattering of screws.
Pics:
1. about half the tiles removed, showing the luan
2. Luan removed
3. Plywood removed, this is where we stopped.