# Tiling over expansion joint - confused



## jkr77 (Feb 16, 2011)

After reading a number of posts on this site, I am confused as to what to use in order to be able to ceramic/porcelain/stone tile over a concrete expansion joint. I am hoping that someone can set me straight

I have a 16'x16' enclosed three-season porch on the back of my recently purchased house. When I removed the carpeting, it revealed a relatively new (under 6 years) poured concrete floor which seems relatively level and in great shape. However, running directly down the middle of it is a 1" wide expansion joint (I assume I am correct in saying that it is an expansion joint - it is a sawed/manufactured joint that has a 1"x2" insert of wood) While the joint appears fairly level and the wood does not protrude, I certainly don't think I can tile directly over it. 

I originally was thinking that I should use a sheet membrane (like Noble CIS) and size it accordingly to go beyond either 6" or 12" tile. But then I read on here that Schluter Ditra would be a good solution for this type of application.

Can anyone give me some solid advice here? Thanks!


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## woodman58 (Aug 22, 2010)

First off I would take out the wood peice. Wood will rott. They should have used a type of felt (?) made for expantion joints. Put this in place of wood. Ditra is not a crack isolation membrain. You should use a membrain you can find in your area and install per manufacturers recomendations. Then you can use ditra.


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## jkr77 (Feb 16, 2011)

Thanks woodman.

I'm hoping I properly classified it as an expansion joint (versus control joint or cold joint) as I am a humble newbie. The noble CIS membrane I looked at and the explanations on Noble's site led me to believe I am dealing with an expansion joint. I can post a picture tonight

In the event I remove the wood, what should I fill that void with? 

Thanks


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## JazMan (Feb 17, 2007)

Hi 77 & 58, (gee guys, simple common first names like "Jaz" would be nice):laughing:

I like Ditra, use it on most floors, but it's not appropriate for this installation. It's also not the right product after an isolation membrane is used IMO. With Ditra, the original expansion joint has to be honored.

CIS is the way to go. I'm not sure about that one inch width though. An inch wide is kinda nuts. If you get Noble's blessings, the joint may need to be wider than normal, not sure. 

Call Noble at; 800-878-5788 ask for Eric and tell him Jaz told you to call to pick his brain. :thumbsup:

Jaz


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## jkr77 (Feb 16, 2011)

Jaz - thanks a bunch for the info.

I had my wife check the gap and its 3/4", not 1" like I had stated. If I go the CIS route, do I remove the wood and fill the gap, leave the wood, or put something else in there?

Direct moisture not going to be an issue as it is enclosed, but the porch will get humid in the hot weather and quite cold in the winters as its not heated and we live in the northeast.

This site is fantastic, btw

- Jay


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## JazMan (Feb 17, 2007)

Not sure about the piece of wood. I would remove it cuz as Woodman said it's gona rot. You will probably need to fill the void with compacted sand, then place a backer rod in there, then top with an appropriate caulk. Pretty sure Noble will want you to make that joint at least the width of the joint or wider. 

Also depends on the exposure to the sun and other factors. You forgot to list where you live, that's kinda important esp. for this Q. The NE to me means CT-DE-RI-VT-NH-MA-ME, but the weather can vary a bunch between these states.

Jaz


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## jkr77 (Feb 16, 2011)

JazMan said:


> Not sure about the piece of wood. I would remove it cuz as Woodman said it's gona rot. You will probably need to fill the void with compacted sand, then place a backer rod in there, then top with an appropriate caulk. Pretty sure Noble will want you to make that joint at least the width of the joint or wider.
> 
> Also depends on the exposure to the sun and other factors. You forgot to list where you live, that's kinda important esp. for this Q. The NE to me means CT-DE-RI-VT-NH-MA-ME, but the weather can vary a bunch between these states.
> 
> Jaz


Jaz,

Live in New Jersey. I havent pulled out the wood yet - so I'm not certain on the depth of the joint, but I am familiar with backer rod and caulk so I will check with Noble on application. Only our first year in the house, but the space I am referring to does get quite warm in the summer months, and down below freezing in the winter as it isnt heated and all windows on 3 sides.


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## JazMan (Feb 17, 2007)

You're gona need expansion joints at the 8' point both ways and of course around all perimeter walls. 

Jaz


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## jkr77 (Feb 16, 2011)

Jaz,

From a purely practical point of view, given that the enclosed porch is subject to variations in temperature, is tile a better choice than a wood laminate implementation? The reason I ask is because the old carpet in this space was not practical just because it gets musty - put down directly on top of the slab. And a concrete slab (even painted) is really not something we want. Was leaning towards tile because we use the porch in the summer as someplace to relax after being in the pool, and I assumed tile would be more appropriate for the occasional wet feet, than a laminate.

We recently installed a Berry laminate floor in our basement (over Dri-Core) and we love the way that feels and looks. I just am hesitant to use the laminate on the porch because I felt the tile would be less worry. But if I have more reason to be concerned with tile cracking due to temp changes and expansion joints on the slab, I'd be happy to do a laminate of some type.

Thoughts?


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## JazMan (Feb 17, 2007)

Tile is one of a few types of flooring that will work. Laminate definitely not. 

Is the slab at ground level or elevated a bit? Does water run off around the house? Carpeting will get musty even when the floor is suspended and dry. Tell us more.

Jaz


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## jkr77 (Feb 16, 2011)

Jaz,

Best I can do from here at work is attach some pics of the space in question. The porch is elevated approx 2' off the ground and there are no issues with water. These are 'before' pictures and the interior pic still shows the carpet that was laid over the slab. BTW, tile would definitely be our preferred material. In the first picture, the porch is the on the right with the french door









In the next picture you are looking at the inside, facing the ajoining house


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## jkr77 (Feb 16, 2011)

had some pics of the actual joint on my cell phone:


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## woodman58 (Aug 22, 2010)

As long as the room does not get wet, you can put laminate in this area. You must leave an expantion joint around the peremiter.


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## JazMan (Feb 17, 2007)

> As long as the room does not get wet, you can put laminate in this area. You must leave an expantion joint around the peremiter.


 (perimeter)

Well.....maybe, check with the manufacturer about installing in an unconditioned space. 

I would find it hard to believe they would honestly recommend a laminate in a space like that and with a pool to boot. Laminate flooring and "ceramic" tile do not belong in the same paragraph. :yes:

That looks like 3/4" stock, but the space looks wider than 1" to me. But, might be 5/8" furring. Is that a valley I see there? Either way it was not a good plan by who ever did it.

Jaz


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## JazMan (Feb 17, 2007)

I couldn't have said it better myself! :thumbup:

Jaz


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## Marty S. (Oct 31, 2009)

corygrant said:


> We'll It's not too bad the Tilling over Expansion joint because the space is be further moderation because yun po vacancies that are not available it is better to use and held a beautiful house repairs depend on you..:thumbsup::thumbsup::jester:


Can you rephrase that cory? No idea what that means.


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## handy andy (Feb 25, 2011)

*Another idea*

The space with the board is definitely an expansoin joint! It is there because a concrete slab of that size will definitely crack unless it is reinforced with plenty of steel. In the photo, it looks like the concrete has moved away from the board. If that is true and you had tile over it, you would have a crack in the tile the width of the concrete movement. The previous owner probably installed the carpet because it is the cheapest and can tolerate movement between the two concrete pieces.

I too thought about wood laminate flooring because then the expansion joint would not be an issue. But I think the varying temperatures and water drips will likely make this a poor idea.

If this were my home, I would look at one of the following two options:
1. Vinyl click laminate. There are a number of Vinyl products that snap together like wood laminate but would take water drips much better. Some look like wood planks and others look like tile. I looked at one product the other day that was made to look like ceramic tile. I always ask questions like "What makes this product better that the other one?". The clerk informed me that this product had wax in the joints that makes it more water resistant. If you look up 'Alure planks' you will find lots of bad experiences. But there is a new product called Alure Ultra that I would consider. There are many similar products.
2. Ceramic tile. (personally I am partial to ceramic tile). I would lay ceramic tile with a 1/4 inch space directly over the expansion joint. This joint would NOT be grouted, but would be filled with a matching acrylic caulk. This would still allow for *some* concrete movement without cracking tile or Grout. I can see your concrete contracting in the winter months and then expanding in the summer. Depending how much the concrete shifts, and your tolerance to a crack in the floor, you may have to recaulk once a year. This would give you an annual maintenance cost of $10-20 per year. 

I would simply stick the tile directly onto the concrete with a good 'crack prevention' mortar. The experts may advise ditra or some other product to deal with possible concrete expansion.


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## Bud Cline (Mar 12, 2006)

> I would lay ceramic tile with a 1/4 inch space directly over the expansion joint. This joint would NOT be grouted, but would be filled with a matching acrylic caulk. This would still allow for *some* concrete movement without cracking tile or Grout.


That's do-able!
Use MegaFlex to install the tile.


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## jkr77 (Feb 16, 2011)

Handy Andy & Bud - thanks for the feedback, exactly what I was looking for so thanks for taking the time to explain it. (yes Jaz, Ive already thanked you

I am still deliberating. Mainly because I want the look of tile, but I'm not really in favor of a larger 'grout' line over the expansion joint. I guess I was hoping that with the installation of a membrane, or ditra, I could eliminate most of the chances of having the tile crack. Really hard for me to gauge though as I only have less than 9 months in the house - except to say that the porch is not at all climate controlled. The main reason the carpet is out now is because it was mildewed. 

Ceramic tile is definitely an option for us that we'd consider. Handy Andy, I had looked into the Alure planks when I was renovating my basement, but decided to use Berry Flooring laminate instead (based on feedback) but I havent seen any of the Alure products that immitate tile, so I will look that up, thanks.


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## handy andy (Feb 25, 2011)

*Look at grouted vinyl*

Since my last post, I noticed another product that could work. It is a vinyl product that is meant to be grouted. I noticed it at Home Depot next to the Alure products but did not pay much attention. If it is a floating floor, it may work. Worth looking into. 

Also, I keep coming up with more problems/ideas:
1. It ocurred to me that if you had a mildew problem with the carpet, there may have been moisture coming up from the concrete. You could do a moisture test by taping a 3' square of heavy poly onto the floor for a while and see whether you get condensation under it. The result could affect your decision.
2. In your photos, the gap either side of the board makes it look like the two concrete slabs have moved apart. The board would have been tight when the concrete was placed. I suggest you take an accurate measure of this space now (while the weather is cold) and then measure it again after a few weeks of warm weather (late spring). I would not be surprised if it were to close up a little. 
3. Put a straightedge across the expansion joint to see whether there is a little ridge on either side. You may need to chip this off.
4. You seem to feel that a 1/4" grout line is big. If you look around, you will notice some tile installations with 3/8" or larger grout lines. This really is mainly a personal choice but should not be a biggie if the grout color is close to the tile color. 

Let us know what you what you end up doing. (After photos).


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## jkr77 (Feb 16, 2011)

Just wanted to come back to this and follow-up. The tiling is now complete. I went with a porcelain tile (rated for freezing temps) as opposed to natural stone (slate, my first choice) for a few reasons. First, I wanted a narrow tile for the expansion joint area, and secondly, the tile we chose - which emulates hardwood flooring, matches the rest of the house and flows nicely....and lastly, this was less expensive and doesnt need to be sealed.

I went with Pro-Red 963 over the joint which was thin-set, and it came out great - level, even, and well-sealed. I had gotten a few opinions on the condition of the slab and joint, and what product to use, the slab was in very good shape after 7 years with no cracks and deterioration. I also set the tile in the same direction of the joint, with the narrowest tile in this style (4"w x 24"l) t minimize stress across the area where the joint is. The majority of the floor was done with a sanded grout, except for the area (2 rows) over the joint which used a latex-based non-sanded grout in the same almond color.

Here are some pics of the process / progress. All that is left to do now is apply base mouldings once everything is set.

I want to thank everyone here for their input and ideas. I feel like I did the right thing, and did it right, and thats all I was looking for. This site is tremendous.

The before (with carpeting):









The exposed slab/expansion joint before:









The thinset/Pro-Red application:









The tile layout / application:









The finished product (minus mouldings):


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