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esco5710 12-09-2012 01:47 PM

Ready to tile?
First off thanks to everyone that contributed to my other thread on kitchen tiling. Now that i have a better idea on the process, i want to list what i plan to do and see if Im understanding everything correctly.

I plan on removing the plywood underlayment and lay down cement board. I picked this method over the ditra cuz of price and simplicity. Someone recommended using 1/4 cement board. Since i dont know the thickness or grade of the plywood subfloor, is there any drawback going with 1/2 instead? I would assume no if theres enough of clearance for the appliances. And its not in my case. Ive read that you can use unmodified or modified thinset under the cement board? White vs grey is not important for this. As for laying the tile, i think im going with a darker grout so i should probably go with the grey modified thinset? Im still deciding on the which thinset- too many to pick from so i am asking for some recommendations. I also picked up the LASH leveling clips to help with the lippage for the 12x24 tiles. My understanding is i should use a 1/2x1/2x1/2 notched trowel to spread the tile thinset and 1/4x1/4x1/4 to spread the thinset under the cementboard. I should also backbutter the each. Im close to both bigbox stores so if someone can recommended an appropriate thinset and provide feedback on the cementboard thickness i would greatly appreciate it! Feel free to correct anything that ive stated wrong too. Thanks!

oh'mike 12-09-2012 06:23 PM

Backer board add not strength what so ever to the floor---use the 1/4" unless you want the extra height for some reason----

I nail floors with galvanized roofing nails---Rock screws work well but I see no added benefit on a floor---

Use a good quality modified thinset---color is up to you---

Yes to the 1/2" trowel and back buttering for the tile---

Consider renting a bridge saw and but a 4" angle grinder with a diamond blade---those are some long cuts--a smaller saw will work ,however--so use what you own.

esco5710 12-09-2012 07:18 PM

How do you determine whats a good quality thinset?

oh'mike 12-09-2012 07:27 PM

Look for Mepei or Latacrete---Perhaps Bud or Jazman could give you an exact product name---

JazMan 12-09-2012 07:42 PM


Originally Posted by esco5710 (Post 1069811)
How do you determine whats a good quality thinset?

Price is probably the best way since we can't easily test it until you use it. You can use the cheapest thinset, even unmodified under all CBU's. Although some makers recommend modified thinset to set the boards too.

One factor whether to use two different mortars is the size of the job. No point buying both types if it's a small area. I prefer white to set tiles.

With large tiles like you're now using you should buy a medium-bed mortar. There's many brands available. One that is easy to find is Granite & Marble mortar at the orange place. Lowes carries either Mapei or Laticrete and I don't know which at your store.

Make sure the floor is very flat.


esco5710 12-10-2012 07:03 AM

What should i do if i cant determine the thickness or type of plywood was used for the subfloor? Will it be sufficient with the cementboard on top then the tiles? Sry if these questions seem repetitive but im trying to completely understand how it works. Thanks.

hammerlane 12-10-2012 08:26 AM


Originally Posted by esco5710 (Post 1070068)
What should i do if i cant determine the thickness or type of plywood was used for the subfloor?

SHould not be that difficult. Dont know if you have forced air heating with heating ducts and registers but if you take the cover off the register you can usually see the thickness of the subfloor where the elbow/boot joins the register...or better yet take off a floor-located cold air return grate.

JazMan 12-10-2012 04:19 PM

Several ways to determine the thickness. The ones mentioned may work, but often the subfloor is covered with sheet metal so you can't see without prying some away. Another way is to simply drill a small hole someplace, then measure with a tape measure or by using a headed nail held/hooked upside down.

Use 1/4" CBU unless you want to raise the floor higher. Color of grout vs. color of thinset has nothing to do with each other.


esco5710 12-13-2012 11:46 AM

Thanks Jazman... There's currently 1/2 plywood underlayment resting on a thin sheet of wood covering? (doesn't seem like sheet metal but could very well be that) over wood planks (home was built in the 1960s). By laying down cement board over the 1/2 plywood then tiles, the floor is raised roughly 1" 1/4 than the adjoining hallway wood flooring. Keeping the plywood seems extreme to me but I'm a novice and looking for help... Without knowing the quality of the subfloor/ joists etc, should i keep the 1/2 plywood or can I lay the cement board over the sheet metal/ planks (subfloor) then tile over the cement board which would give me a more even flooring? If the 1/2 plywood is necessary for the structure where can i find a higher saddle/ transition that would minimize the height difference? The ones Ive seen at the big box stores were 1/2" in height which would not hide the cement board/ thinset/ tiles. Thanks!

JazMan 12-13-2012 01:54 PM


There's currently 1/2 plywood underlayment resting on a thin sheet of wood covering? (doesn't seem like sheet metal but could very well be that) over wood planks (home was built in the 1960s).
Esco, forgive me, but you're gonna hafta do better than that. If you can't tell the difference between sheet metal and wood, how are we gonna help you install this floor?

So it sounds you're saying your subfloor is planks, (are they diagonal or perpendicular to the joists?). Over that is a thin layer of ply, (is it close to 1/4"?), might be luaun underlayment for vinyl floor that might still be there or was removed). Then over that is 1/2" ply? All that could be, but doesn't sound right.

I'd like to know exactly what you've got with no guessing. Ideally you probably should remove the 1/2" and that thin ply under it to get the the plank subfloor. Inspect/repair the planks, then install 1/2" or thicker ply and then the concrete board etc.

You're concerned about the height of the two rooms but I don't think you mentioned what's on the other floor. Rooms are liable to be at different levels unless you install the same floors on them. I wouldn't be too concerned unless it's over an inch variation for residential floors. Commercial is different cuz some people are looking for a place to trip.


esco5710 12-13-2012 02:11 PM

Jazman, it definitely doesnt look or feel like metal but since you mentioned that was common- i assumed thats what it could be. The planks run diagonal On top of that is this very thing covering- not sure if its leftover from the previous flooring (which i dont know what that was). Then the 1/2" of plywood that had linoleum Flooring. I will try to take pics to give you a visual of the layers.

esco5710 12-13-2012 02:13 PM

I have hardwood flooring in the hallway leading to the kitchen.

JazMan 12-13-2012 02:29 PM

OK, so the other area is 3/4" above the planks and once you do the kitchen the way I mentioned you will be about 1/2" higher than the hardwood. (Ply, concrete board, tile). Note: you may have to install 5/8" underlayment depending on the type, size and condition of the planks.

You'll be able to install a 1/2" +- hardwood reducer over the hardwood butting within 1/8" of the tiles. Or maybe a hardwood "T" molding, or make a saddle.


esco5710 12-13-2012 07:06 PM

Jazman, essentially, you're suggesting I remove the thin covering/ wood piece and relay the 1/2 plywood on top of the planks? The thin piece is very thin, <1/4 I would say. Do you think it would make a noticeable difference in height? Can I use 1/4 of plywood instead to lay the cement board on then tile or is that not recommended? Thanks!

JazMan 12-13-2012 07:40 PM

There should be no 1/4" anything in a tile installation sandwich. Regardless, I think it would be a good idea to get down to the planks and refasten/repair as necessary. Chances are the planks are not t&g and the nails may have worked a bit loose by now.

What kind of shape is the 1/2" you're looking at? What was on it? I might consider leaving what you've got, just refastening if I thought everything was in good shape and didn't mind the extra height.

But let's see what other info you give.

I said;

Note: you may have to install 5/8" underlayment depending on the type, size and condition of the planks.
I was asking for an answer. Did we ever talk about the framing yet?

We went in circles a little cuz in your first post I think you went into too many subject. You asked about; plywood types & thickness, concrete board, Ditra, thinset mortars, Lash, trowels, backbuttering, and large tile sizes. We can help with all those, but not all at once. So, let's start with the joists.

Size, spacing, unsupported span to the inch. Species and grade if at all possible. Basement, crawl space?


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