What are my options for tiling over an uneven concrete floor?

Question

UPDATE:

After doing my research, it seems like I will need to level the floor before tiling. My carpenter doesn't know how to it so I will have to get a contractor to do this job. How much would it roughly cost to level a 550sf floor in Chicago area? I will get a quotes but it would be nice to know the ballpark figure beforehand.

Here are some photos how the floor look.

https://photos.google.com/share/AF1QipMOEk8rZGFprcejd63FeoRT2TUbdMbJWp6bJvgrhbEZAygfvkO4JLow_MCLlDNp3A?key=VUlFNmUyNXZnRVRGSFd5RmVyQ2s2WDg2Q0FnaGRR

My basement of about 600 square feet had vinyl tiles and carpet. I ripped everything out to install porcelain tiles. However, the concrete floor is uneven and wavy. The basement is a rental unit. Some of slopes are about 2,3 inches deep. It would cost me a lot for the self level compound like levelQuik ($36/ 40lbs bag that covers about 40 sq feet 1/8" deep)

My contractor has already installed the porcelain tiles in the kitchen. They show lippage but don't look too bad with wide spacer. I'm just concerned if they will break or come off later because of the uneven floor they are on.

If I don't level the floor and install the tiles anyway with either

vinyl planks like this http://www.homedepot.com/p/TrafficMASTER-Allure-6-in-x-36-in-Canadian-Hewn-Oak-Luxury-Vinyl-Plank-Flooring-24-sq-ft-Case-81314/205893535

or

porcelain tiles like this http://www.homedepot.com/p/MS-International-Classico-Blanco-12-in-x-24-in-Glazed-Porcelain-Floor-and-Wall-Tile-16-sq-ft-case-NHDCLASBLA1224/204800225

will they lose adhesive or break and come off later? What are my options here?

Answer 1

One option would to roughly fill the deep depressions with a relatively inexpensive mortar mix, and only then pull out the self-levelling stuff so you can use less of it.

Answer 2

Big tiles like that will be very difficult to get to look nice with such a wavy floor. If you don't mind some waviness you could use smaller tile and let it go with the flow to some extent. The requirements for a pro quality job are pretty strict, though probably don't apply to your case where some lippage is ok.

For tiles with all edges less than 15", the maximum allowable variation is 1/4" in 10' and no more than 1/16" in 12". For large format tiles with one edge greater than 15" and for natural stone tiles, the maximum allowable substrate variation can be no more the 1/8" in 10' and 1/16" in 24".

Either way you won't have an issue with adhesion if you follow the instructions for the thinset and ensure complete coverage thinset under the tile (no voids).

But be mindful of any cracks in the floor, those can easily cause the same cracks to appear in the floor. You'd want to put down at least a couple coats of RedGuard or other crack prevention membrane in areas near cracks. Cracks with vertical deflections are another story, there is not much you can do about those besides pray.

I second Ecnerwal's recommendation to use an inexpensive mortar mix to get it pretty close, and then finish it off with a thin layer of LevelQuik to smooth out your rough patches.

Also remember your floor does not need to be level, it needs to be flat. No big deal if it slopes to one side as long as you get it flat.

If you want really good advice on any tile questions, head over to this tile forum and ask for some advice. They are super helpful to DIYers. http://www.johnbridge.com/vbulletin/forumdisplay.php?f=1

Answer 3

I would recommend using cement mix rather than mortar mix for the large depressions and then use mortar mix to even out the rest. As was said above, while the floor doesn't have to be level, it does have to be EVEN in order to lay tile. If you lay tile on an uneven floor it WILL ultimately fail AND will have to be replaced in a short period of time. This approach allows you to use less LevelQuik which is the most expensive of the underlayment materials. Another flooring option would be a floating snap-in engineered floor. If you go that route, you still must even out the major depressions and test the floor for vapor content. -I was a bathroom and flooring contractor for 15 years. Good luck!

Answer 4

Estimate for fixing the floor, installing flooring or both as a single job? A tile or snap-in floor would run about the same material-wise but labor costs would be different. Before ANYTHING, you have to even the floor. The moisture content of the subfloor is critical. Being a basement, I would probably go with tile. The other alternative is a polished concrete floor. You can get an estimate at Home Depot--there is a charge but it is refunded on the backend of the install. There are many different costs and labor scopes differ for each task and the materials involved. I would start with filling the deep depressions. If it ends up not going well DYI, then you can pay someone else. I recommend doing whatever tasks you're comfortable with to keep overall costs down.

Answer 5

Also, if you decide to go with outside contractor, I would probably split this upgrade into two jobs-1: resurfacing the floor and 2: installing flooring. I think you could get a better price for each job as separate.