Trying to install ceramic tile on unlevel floor in 1890's era house

Kichigaidave · 06-10-2010, 08:44 PM

Here's what I've run into:

Approx: 10 x 14 room.

Pulled up nasty old carpet & pad. Pulled up old tile and found 1/4" plywood subfloor over wood planking (planking is approx 5-1/2" wide, 3/4" thick of varying lengths). There are varying dips, valleys, humps, etc... Mostly due to the fact the room is half over the basement and half over a crawl space. The highest part of the room is right over the basement foundation wall where it then transistions over the crawl space. For a 100+ year old house it's not too bad, but not good enough for ceramic tile. The worst is probably 2-1/2" from the highest to lowest point, generally slopes from east to west.

My Plan: (looking for suggestions, ideas, advice, etc...) Due to cost saving, limited budget, & desire to do it myself (with help of course); this will be a strictly DIY project.

1) I am planning to rip up the 1/4 plywood due to some damage, and get down to the planks. That way I can repair some that are loose, etc...
2) Put down new plywood over the planks. I was thinking of cutting and using different thicknesses to try to even out some of the floor. Not sure if this is a good idea or not.
3) Then put down some Hardibacker cement board. Using a thin layer of thinset and securing with cement board screws.
4) Use a latex primer & finally a self leveling compound. Hopefully this will give me a floor level enough to install the ceramic tile. (it's a 13x13" tile)

flooringgirl · 06-10-2010, 10:03 PM

I'd say you have it all figured out!! Thumbs up!

Tia

Kichigaidave · 06-10-2010, 10:35 PM

My one worry is I don't think I can use different size plywood, because then I'd have to put the cement board directly over them. Basically matching seams etc... I think that they're supposed to be staggered. Seams and over lapping with the layers to strengthen and have less movement. It would be easier to use the self leveler and then put on the cement board, but I don't think you can do that. I don't think the self leveler compound takes nails, staples, or screws well. Hmmm...

flooringgirl · 06-10-2010, 10:53 PM

Quote:

Originally Posted by Kichigaidave

My one worry is I don't think I can use different size plywood, because then I'd have to put the cement board directly over them. Basically matching seams etc... I think that they're supposed to be staggered. Seams and over lapping with the layers to strengthen and have less movement. It would be easier to use the self leveler and then put on the cement board, but I don't think you can do that. I don't think the self leveler compound takes nails, staples, or screws well. Hmmm...

Correct ... do what you need to do to make it all as even as possible and then use the self-leveler! Be sure to both mortar and screw the cement board, and there is no need for primer. Just make sure you have a total of 1-1/4" subfloor for the tile.

Tia

JazMan · 06-10-2010, 11:04 PM

The only part I like is # 1, removing the 1/4" ply. You have to remove it regardless of its condition.

#2 is a very bad plan as you've realized.

SLC to level from zero to over 2" is very costly and hard to do. You're better off hiring someone to do a 'mud job' for you. But remember that may not be possible to do depending on the layout of the room and where the doors are is relation to the levels of the room. The mud needs to be at least 3/4" thick where to old floor is the highest.

You may not to be able get this floor level without carpentry work. However, a tiled floor does not have to be level, it should be flat though. Talking about carpentry, have you determined that the joists system is stiff enough for tiles in the first place?

Jaz

flooringgirl · 06-10-2010, 11:18 PM

Hi Jaz!

What is the difference between level and flat? I'm thinking if he can use underlayments to bring things close, only a small amount of leveling should be required. Maybe a 1/4" or less, which could be accomplished with a Webcrete product. Thoughts?

Tia

JazMan · 06-10-2010, 11:30 PM

Level = a horizontal surface that is in plane to its self in all directions.

Flat = a surface that in plane.

A floor might be flat, and so can your wall or therefore any surface that is between 0 & 90 degrees.

As you can see, level and flat are very different.

Dave stated he has a rise of over 2". How would you make that flat without creating a step at some of the doorways? That's why I mentioned it may not be doable.

Where do you get 1/4" out of level idea? Also, which SLC are you thinking that doesn't require a primer?

Jaz

flooringgirl · 06-11-2010, 12:18 AM

Quote:

Originally Posted by JazMan

Level = a horizontal surface that is in plane to its self in all directions.

Flat = a surface that in plane.

A floor might be flat, and so can your wall or therefore any surface that is between 0 & 90 degrees.

As you can see, level and flat are very different.

Dave stated he has a rise of over 2". How would you make that flat without creating a step at some of the doorways? That's why I mentioned it may not be doable.

Where do you get 1/4" out of level idea? Also, which SLC are you thinking that doesn't require a primer?

Jaz

Of course there will be variations at the doorways. I am saying that if he is able to bring his subfloors & underlayments close to level/flat, he can use a product which will easily smooth the slight variations on the surface. Actually, the way you explained it, level is plane and flat is plane. Always learning here, not seeing the difference?

If there is a big variation in the initial floor, it can be solved by mudding the low spots, underlaying, then skim-coating as necessary. I get the 1/4" out of level idea because after the appropriate underlay, there should only be that or much less.

Tia

JazMan · 06-11-2010, 12:33 AM

Please xplain to us how you can make an out of level floor close to level using plywood?

Who's not seeing the difference between level and flat?

So you're saying you might "mud" the low spots then install a CBU over it? You're kiddin' right?

Jaz

flooringgirl · 06-11-2010, 12:49 AM

Quote:

Originally Posted by JazMan

Please xplain to us how you can make an out of level floor close to level using plywood?

Who's not seeing the difference between level and flat?

So you're saying you might "mud" the low spots then install a CBU over it? You're kiddin' right?

Jaz

Yeah, kidding. Read my post to you on the other thread and realize that I know you have a burr for me. I'll put up verification of anything out of my mouth or fingers if needed, would never lead a customer or DIY person wrong. We've used levelers for up to 4" in commercial jobs, so yes, it is possible.

Tia

JazMan · 06-11-2010, 01:43 AM

Wrong Tia,

The problem is when someone comes to these forums claiming to have experience and knowledge with no introduction or ways for the people to check their background and gives advise that is not in keeping with industry standards or norms.

It is the duty of the other pros to challenge those that offer DIY's bad info. Heck if they want bad info, they can just go to their local big box store and get plenty of that. Actually, bad info from the big box stores is why they're here in the first place.

Jaz