Found issues in the bathroom.

[Clone TIE Pilot]

Inspecting the bathroom floor further, it is constructed as follows: plywood, underlayerment paper, plywood, thinset, and tile. From what I have read online this is not an acceptable build method for bathroom floors. That there should be a layer between the tiles/thinset and plywood, either mortar, seperation membrane, or cement board. Bad thing is either method will raise the floor which will affect other measurements and clearances in the bathroom. Can't find an answer if cement board requires one or two layers of plywood or if you can supstitute the second layer of plywood with membrane or cement board.

 

[NJ Longroof]

Three methods we use at work.
1. Plywood, tar paper, wire lathe dry pack cement (mudjob). Mud can be brought to whatever height needed.
2. If you subfloor is relatively level and close in height to what you need...wire lathe separated 1/2 inch from each other scratch coat floor with latex modified thinset mortar.
3. Self leveling compound over the sub floor. Use a primer over subfloor mix and poor leveler...this sh*t finds any hole and will pour through so caulk any joints, cracks,hole, screws ect before priming. Pour and it does its thing.
We never use cement board on the floor and if we tile over cement board no warranty

Now you are ready to tile

 

[ck80]

Inspecting the bathroom floor further, it is constructed as follows: plywood, underlayerment paper, plywood, thinset, and tile. From what I have read online this is not an acceptable build method for bathroom floors. That there should be a layer between the tiles/thinset and plywood, either mortar, seperation membrane, or cement board. Bad thing is either method will raise the floor which will affect other measurements and clearances in the bathroom. Can't find an answer if cement board requires one or two layers of plywood or if you can supstitute the second layer of plywood with membrane or cement board.

Njtileguy has the right advice.

Just so you understand what you're after, grout cracks and comes out, and tile cracks, when there is flex or give to the floor. You should be able to stand on and walk about on the prepared surface without any springiness or give. That's why all the concrete board sheets on plywood on whatever is bad. Each layer can flex somewhat compared to the other. You're after a unified hard surface.

Once you've got that solid slab going on you're ready to tile.

However. Before you start, and depending on your level of OCD, a warning. Downside of self leveling compound beyond going through any crack or crevice is, especially in an older home, if your center beam has been sagging. Your floor and ceiling may slope to the side, but equally. Self leveling compound gives you true level, not just filling in the low spot in a dip. It will run to where it lowest and build from there. So before you use it, if you use it, take a level and check the floors. Cause if you're ocd you don't want your baseboard, toilet lid, vanity top, bathtub, etc to sit at an angle compared to the ceiling.

To me, I can live with a inch drop or so slop across a room. But I feel unsteady if the trim and baseboards aren't parallel, and having a wall appear shorter on the other side of the room or the ceiling coming downwards.... it'd drive me nuts. Back in the day I rented a townhome where walls weren't square and trim rose and dipped, couldn't stand it

If you've got a slope to the floor you can decide whether to hydraulic jack and levelout that beam below at risk of cracking walls and such in the process, or, just live with what you have been and use a different method.

Three methods we use at work.
1. Plywood, tar paper, wire lathe dry pack cement (mudjob). Mud can be brought to whatever height needed.
2. If you subfloor is relatively level and close in height to what you need...wire lathe separated 1/2 inch from each other scratch coat floor with latex modified thinset mortar.
3. Self leveling compound over the sub floor. Use a primer over subfloor mix and poor leveler...this sh*t finds any hole and will pour through so caulk any joints, cracks,hole, screws ect before priming. Pour and it does its thing.
We never use cement board on the floor and if we tile over cement board no warranty

Now you are ready to tile

Agreed.

 

[NJ Longroof]

And dont cheap out on the thinset mortar either get a good brand

 

[Clone TIE Pilot]

It looks like portions of both layers of the plywood subfloor will need to be replaced, at least around the toilet and under the bathtub. Some of the bottom layer of plywood near the toilet has started to delaminate and the plywood under the tub has completely delaminated. Probably going to have to rip the floor down to the joists in those areas. Moreover, it appears they didn't nail the plywood down enough either and the nails are rusty.

The bathroom in question only has a acrylic bathtub with a shower head. No separate shower stall. Are you recommending using dry pack mud for the whole bathroom floor? It looks like the builders did not use any mortar under the bathtub. The problem bathroom is in the original part of the house which is a 60's kit house. No idea which company made it.

 

[NJ Longroof]

We mud the main floor and shower if it is that type of shower.

 

[NJ Longroof]

Mud gives you a nice stable level base for you tile and you can bring the height up if needed instead of multiple layer and the possible movement. It is an old school method that will hold up for decades if done properly

 

[Clone TIE Pilot]

Ok, I understand now, thanks for the advice. I suspect the builder may have just used tile adhesive directly on the plywood. The residue on the backside of the loose tiles is tan and plastic like. Doesn't feel like a masonry product.

 

[Turbo Zach]

One way to learn. If you decide to hire it done? Make sure you get good references to the contractor you choose.

 

[Bonnewagon]

NJtileguy is right. I just finished a renovation of my hundred year old bathroom. The floor was those old little hexagonal things that are not tile, but actual stone. They were set into a mud job several inches thick and aside from a few settling cracks, they were solid so I left them alone. I used white grout to fill in the cracks and restore the look of the old cement. A prior owned had hammered nails into the plaster walls for some crappy wallboard. I had to repair the cracked plaster walls that had cement backing on furring strips. The only tiles I used were new coving tiles around the base of the wall. This is very old school that no one wants to do anymore because of the time involved. But I know how durable that type of material is. To complete the period look I bought a fiberglass clawfoot tub, freestanding shower and all. It should last another hundred years.