Underlayment For Floor Tile - South Florida

ETHICS05

I'd like to get your opinions on underlayment - yes or no - for floor tile over concrete slab for south Florida applications for new construction.

Up to this point my tile guy has been using Ultraflex thinset with no "crack paper" or any other type of underlayment and the results have been good, but not perfect. Still run into some cracking, but nothing major. Are my expectations too high here?

There are many underlayment products out there and some can get very expensive; however, I'd like to know what you've encountered.

Are they worth it? If so, what seems to be the better products out there for the best results.

Thanks!

Mike Finley

What would you consider to be very expensive? Ditra is about $1 a square foot.

MattCoops

CBU is even cheaper

__________________
Matt with Cupan Custom Tile & Paint of Lowell, Massachusetts
Design and installation of ceramic tile and natural stone for floor, wall, and countertops
(978) 601-8774 | cupantile@gmail.com | view tile pictures and more

Bud Cline

UltraFlex is a good product for the price but it isn't very forgiving and offers not near the flexibility that is available in other products even tho they use "flex" in labeling the product.

Custom's MegaFlex would do a better job but is twice the cost.

There are several good flexible membranes available and that seems to be the way to go today. Not only do they offer more flexibilty than regular thinsets they also isolate the tile from the structure and will not allow cracks in a substrate to telegraph through to the tile in most cases.

Schluter's DITRA is a top of the line product as is Noble's CIS. Custom Building Products offers a product called EasyMat and in your area I think MerKrete's isolation membrane is also available.

I don't know of any product that would be referred to as a "crack paper" that is recognized by the tile industry with the exception of that Tavy stuff and we won't go there.

PS: CBU's CAN NOT be used over concrete.

Teetorbilt

Everybody that I see does as you say. I remod and consider it more acceptable after the slab has settled (for about 20 yrs.).

I see it done every day but you know that it's going to break at sometime given everybody working to 'code'. aka 'bare minimum'.

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HallisseyDesign

Have you guys ever used 1/4" hardi board for tile jobs? I use it and it is nice when you have to take it up too! Don't ask !! It is 9 bucks a sheet. I have seen in southern California the guys lay the tile right on the concrete and go. I am normally laying tile on subflooring so throwing concrete on plywood is not a good idea. The only way it comes up is with a jackhammer and a nice big flat blade. Don't ask again!

JustaFramer

A jackhammer wtf. A bosch demo hammer with a chisel bit is all it would take. However I have demo'd some tile in my time and all that is required is a wonder bar and hammer.

I used to prep for a tile setter. I would use thinset and durarock or hardi backer. Never prepped on a slab so I wouldn't know the best way.

Mike Finley

There is a right way to do this type of work and there is a wrong way. If you're not aware of the Tile Council Of America, you might want to buy their annual, handbook that describes the industry standards to lay any type of tile over any substrate. Your description of your methods isn't an approved method for this scenario.

In another post you said you new a whole lot more than others, your reply here is now showing maybe that isn't so. Buy that hand book. There is very little difference in doing something that will last 50 years and something that will last 5.

HallisseyDesign

Hey I thank you for telling me that is wrong. Like in the other thread I also added I worked for a construction group in cali. He tought me how to lay tile. He said it was right and the inspector sitting over his shoulder said th same thing. I will buy that book.

JustaFramer

A inspector sitting over the shoulder of a tile setter. Maybe they do that in Cali. But the only time I have seen a inspector look at tile was on the final inspection of a finished house.

Mike Finley

Yeah. There are only 2 inspections associated with residential tile work that I know of. One would be for mud pans and the other would be if they have adopted the the 2006 IRC and would be for no more drywall in a wet area under tile.

HallisseyDesign

The inspector was there checking for other stuff done in the bathroom by his guys. So I got the white glove test when laying it.

JustaFramer

Did they finally put that in the code books. I haven't seen the 06 IRC. I don't think I have seen tile on greenboard since 01. When I was doing some prep work for tile in 02-04 it was either durarock or hardi in wet spots.
Inspectors where not needed to be called back then. I knew there was issues with tile insurance wise when I was asked several time if there was tile in my residence. When I was shopping for home insurance.I was told they wouldn't give me a policy if it did.

ChrWright

Ditra is a great product, as long as there are no floor height/transition issues. On older, fully cured concrete that is stable I might consider laying tile directly to slab using modified thinsets & grouts. Don't forget control joints for larger areas and be careful of cuts/control joints in concrete slabs (like basements).

Laticrete Blue 92 & 9235 are good slip/isolation membranes but can get expensive. They're also good if you need to stay thin.


TCA guidelines are a MUST have for anyone who lays tile or hires it out.

I'd trust the pimpled kid at Lowes more than I would an inspector on how to install tile right.... Some people have ten years experience, and some have one year of experience, ten times.

ETHICS05

Thanks guys! Good stuff!