Tile on plywood w/o backer

[JEBalles]

As part of a kitchen renovation, we had our linoleum floor replaced with ceramic tile. The ceramic tile was installed directly onto the subfloor without a backer of any kind. The subfloor consists of the original wood floor and a layer of 1/2" plywood on top. We had the entire floor tiled with the intent of installing new cabinets on the tile.

My questions are:
1) Are there any circumstances under which this is an acceptable form of installation (my research indicates no)?
2) If we go ahead with the cabinet installation and the tile ends up cracking, is it reasonable feasible to take up all of the tile except for underneath the cabinets and then install new tile up to the cabinets with a proper cement backer? Or would the cabinets need to be removed to replace the whole floor?

[cx]

Welcome, Joe.

1. Your research has produced a correct result.

While there is an industry accepted method of bonding tile directly to a plywood subfloor (TCNA Method F150), it requires, among other things, a first layer of T&G plywood and a second layer of plywood, each layer properly, and differently, installed over joists spaced no more than 16" on center. The joist structure must also meet the necessary L/360 deflection minimums. You're clearly lacking in the subflooring department, but we can't determine whether you meet the rest of the requirements with the information provided.

We (TYW) generally recommend against the method, even though it is industry accepted if properly executed, because it provides no tolerance at all for error.

2. You could feasibly remove only the tile outside the cabinet footprint, but it's not always as easy as it might sound.

My opinion; worth price charged.

[JEBalles]

Okay, sounds like I should move ahead with cabinet installation and hope the tile holds up. If it's feasible (however much more difficult) to replace the tile around the cabinets, then I'm guessing it's probably not worth having someone else come in now and reinstall the tile correctly.

What would be the best method for removing the tile around the cabinets? Angle grinder? Just trying to get an idea of what might be involved if it comes to that. The cabinets are IKEA, which sit on feet instead of traditional built up bases, so I'm wondering if that would make it easier.

[cx]

Have you checked your joist structure to determine if your floor qualified for a ceramic tile installation at all?

If you paid for an installation that complied with industry standards your best option would be to have the floor re-done now before your project goes any further. Have you a written contract for this tile work?

Never seen any such IKEA cabinets and can't really comment. Do they have a toe kick at all? Is it removable after installation?

I would start such tile removal with a diamond blade on a toe-kick saw.

My opinion; worth price charged.

[john619]

You really should check your joist spans, because if that is off then I would pull the tile and install correctly. Much easier to do now. Installing backer and new tile and leaving cabs in place will cause the Dishwasher to be unable to be removed and or replaced. The stove and refer may have similar issues.

[JEBalles]

I did not check the joist structure ahead of time, but I believe it does qualify. Assuming Douglas fir and 50 psf live load, 20 psf dead load, the max span is 12' 7" for 2x8 dimensional lumber at 16" on center (source: American Wood Council span calculator). Our span is 10' 6" and the joists are old rough sawn 2x8 (house is over 100 years old), so there is extra margin there.

Tile job was under the table, so we don't have a written contract. I am checking to see if they will warranty their work (the company does a lot of tiling from what I can tell).

IKEA cabinets have a plastic toe kick that clips/slides on the feet, so it should be fairly easy to remove.

Stove is a slide in and there should be plenty of room above the fridge. The dishwasher has a minimum assembled height of 32" and maximum of 34.5". Re-installing with a cement backer should only add about half an inch right? I don't think that'd cause an issue pulling it out.

[jadnashua]

Unless you want to match heights, nobody recommends 1/2" cbu on a floor, so 1/4" is fine, and if you are tight on height, there are membranes that can be used that are thinner, eg., Ditra is about 1/8". The tile backers are for compatibility, not for strength.

[ss3964spd]

Any idea what grade plywood was used, Joe, or how it was installed? Was it laid with its long edges perpendicular to the joists? Was it screwed to the joists or to the original wood flooring? Was any kind of adhesive used between the two? Did the original flooring get screwed down first?

[Kman]

What's under the 1/2" plywood? It looks like tongue and groove hardwood flooring in your picture. If that's the case, what's under that?

Edit: I just saw on your picture where the subfloor is directly on the joists. But still important to know what's under the 1/2" ply.

[JEBalles]

Don’t know much about the plywood or installation - it was done long before I purchased the house. The long edges may have been perpendicular to the joists and I think they were nailed along the edges of the plywood to the wood floor, but can’t remember exactly. The floor consists of only the hardwood (fastened directly to joists) and 1/2” plywood.

[Kman]

Yes, specifically the hardwood underneath was what I was wondering about, if you know. Is it visible from underneath, maybe?

[JEBalles]

Hardwood is visible from underneath. Planks are 7/8" thick x 2 1/2" wide, tongue and groove.