# tile over exterior concrete?



## BlueMoonBean (Feb 13, 2006)

Hello, 

We just contracted for our first home to be built (fairly standard entry-level home on concrete slab)  . The home has what the builder describes as a floating concrete porch, sidewalks, and back patio. It seems from the builders' literature that they expect these areas to crack as a result of settling rather quickly. Is there any way to cover these areas, with tile or pavers, set into some sort of matrix that would have enough flexibility to ride out the cracking movement of the concrete? 

This is our first home and we look forward to working on it, but we'll need a lot of help to know how to do things the right way the first time. Just from lurking on these forums for the last few weeks, I've realized how awful some of the home improvement store advice can be, and we don't have enough money to waste on doing a job twice. 

Thanks in advance, 

Katherine
(excited new homeowner-to-be)


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## FearnConstruction (Feb 13, 2006)

If concrete is cracking, and tile is installed over it, most of the time the tile will separate from each other at the grout joint. In som bad instances the tile itself will crack. I would say that the smaller the tile, the better making the possibilities better for a grout space separation rather than a "mid-tile" crack. I would use a generous bed of "Flex Bond" mortar. It is more expensive but it moves with cracks better. Use a deep notched trowel.


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## R&D Tile (Feb 6, 2006)

BlueMoonBean said:


> Hello,
> 
> We just contracted for our first home to be built (fairly standard entry-level home on concrete slab)  . The home has what the builder describes as a floating concrete porch, sidewalks, and back patio. It seems from the builders' literature that they expect these areas to crack as a result of settling rather quickly. Is there any way to cover these areas, with tile or pavers, set into some sort of matrix that would have enough flexibility to ride out the cracking movement of the concrete?
> 
> ...


Where did you find this guy, Floating sidewalks and patio made out of concrete, what does that mean, and he told you he expects it to crack?, boy, I guess that covers any problems you might have and him from any warrantees, yes concrete can crack and usually does at some time, I never gave guarantees for flat work, but proper sub base materials and doing it correctly can isure the best survival.

Where do plan on tiling, just the indoor slabs?, if so, install a crack isolation membrane, then your tile. Flexbond will help, but in no way compares to using a membrane and the notch used depends on the tile, thicker isn't better here.

Just remember, NO membrane will help with vertical cracking, if the slab cracks and doesn't stay even, kiss the installation good buy, but don't woory, this doesn't happen often indoors.

If tile is bridging an area that cracks without a membrane, very good chance the tile will crack right down the middle and follow that crack below.


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## BlueMoonBean (Feb 13, 2006)

R&D Tile said:


> Where did you find this guy, Floating sidewalks and patio made out of concrete, what does that mean, and he told you he expects it to crack?


I know - we were a little freaked out by that!  It was in the homeowners' manual that the company provided after we signed our contract. The manual was describing how to care for the exterior porch/patio space to prevent cracking (like not spraying it with tons of cold water on a hot July day), but also emphasized the fact that the exterior concrete areas aren't attached to the main foundation and aren't covered by the structural warranty. Here in NC, I've seen lots of concrete sidewalks and patios that get hairline cracks very quickly, and I'm guessing that's something that's hard to prevent with the quick temperature changes we get. 

I'm interested in tiling the front porch area of the exterior of the house. (I'm not sure, but I think I should have put this thread on the landscaping section. Sorry  )

I found this link: 

http://doityourself.com/concrete/tileapatio.htm 

and was wondering whether the advice given there is solid?

Thanks so much for the advice! I really appreciate it!

- Katherine


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## R&D Tile (Feb 6, 2006)

Is this area exposed to the weather?, if so, I would install a crack isolation membrane over this area, then use a good modified thinset and Porcelain tile, yes, leave a gap of the size of the grout joint and caulk this gap, it's for expansion, this should always be done indoors as well.

Also, all of this should be done in temps above 55 for at least 72 hrs. day and night.


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## rrlarson (Nov 18, 2008)

*Exterior Tile Installation*

Tiling a concrete slab should not be a problem if you follow the advice from previous posts: use an expansion gap, use flexbond or a similar thin-set mortar, and follow the instructions on the packaging for temperature, trowel size, etc. Also, ask your installer not to seal the concrete if you are planning to tile over it.

One thing I didn't see mentioned was the type of tile that should be used outside. Please ensure that any stone, porcelain or ceramic tile has the proper rating to be used outside. I don't know what your winter temperatures are, but if you get freezing weather, this is especially important. Tiles have water absorption ratings. If they are too high, they will pull in water from the environment (including from the air - so this still applies to covered porches) and this water can freeze, expand, and crack the tiles. Most people think stone tiles are fine to use outside, since they are a natural product. But because they are cut thin, the absorption rating still applies. Limestone is great in warm weather, but many types will crack in places with freezing temperatures...most granite will be fine. Porcelain and some ceramic tiles will be fine...look for an absorption rating of <3%.

The other caution I will mention is to be aware of how smooth the tiles are. I had a customer who had to close down his store during the first snow storm because he installed polished marble tile at the exterior entrance to his store. It is so slippery, he couldn't risk people falling down. Make sure you get a tile with a decent texture to it.

Other than that, good luck with your new home! I work at a home improvement store and would advise that you read up on projects before starting them. Not that you wouldn't, just that many people assume the employees are experts. And from my experience, most employees have some training, but haven't really done the projects themselves. Not only that, but they don't usually have time to sit and walk you through each step of a project. (And really, you cannot expect an expert at $7 an hour when an experienced installer makes much much more!)

Over 80% of the questions people ask are explained in the instructions on the back of the products. Not to say you shouldn't ask, but definitely verify before using a product. And there are dozens of books at Lowe's and Home Depots. Grab a few and sit down in one of their design centers to read through them. No one will mind, and you'll get ideas of questions you need to ask.

Have fun with your home!


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## yesitsconcrete (May 11, 2008)

i wouldn't worry about conc anywhere IF your gc's sub places the right jnt pattern AND cuts/saws/installs jnts at the right TIME,,, seems pretty basic but that's the main reason for random cracking in conc,,, if you do get some crks, you may be surprised to see american concrete institute mentioned who's standards allow for some random cracking.

if it were OUR house in nc, we wouldn't be placing tile outside over conc,,, have removed too much of it that's cracked/delaminated - either from a conc crk reflecting UP thru the tile OR rain penetrating the grout ( sealing's an annual chore, btw ! ) & turning to ice which eventually lifts the tile.

i'm not aware of any tile that's knowledgeable of its location - its either tile or it isn't far's i know :whistling2: that being said, marble absorbs less wtr than granite yet granite's stronger - limestone's been a respected bldg mtl for yrs - it it weren't, we wouldn't still build w/it.

' snow storm blished marble tile ' = ? ? ?

the ONLY time i listen to any apron store employee's when they can convince me THEY're retired from the particular trade for which i'm shopping - ie; electrical & plumbing, i only deal w/2 guys,,, if they're not on-duty, i walk,,, trade supply houses know their wholesale customers're & have little patience for the ignorant h/o which i yam often :laughing:

btw, here's something you didn't ask - basement water leakage's usually ONLY covered by your h/o warranty in the FIRST yr,,, after that, you're on your own ( wtr doesn't usually show up til AFTER the 1st yr )

' cold water on a hot day ' ?????? what idiot wrote that ??????


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