Ditra

[Robby]

I have been installing tile independently since 95. I have always used concrete board as an under-layment for flooring, with the goal being an inch and an eight of subfloor underneath the tile.

I am wanting to jump on the Ditra bandwagon, but I would like to hear what you have to say first.

So do you guys use Ditra over three quarter inch osb with no problems.

So if Ditra is all that it is "cracked up" to be, when should you NOT use Ditra.

I appreciate your response

Robby

http://www.mctp.biz/

[cx]

Welcome back, Robby.

If you're in the tile industry it'll help if you'll add some information to that effect to your User Profile so folks can look there and see what kinda fella they're having the conversation with.

When not to use Ditra? When it's not indicated by the manufacturer for such use. Other than that it's just a matter of choice. Some folks like it, some folks like other substrates. Schluter's published installation instructions and requirements are pretty clear and comprehensive.

If you'll type Ditra into the Advanced Search feature and ask for Titles you'll surely find some helpful information on preference in the first 500 or so threads that appear.

[MHI]

Hi Robby.

I haven't had any problems when used according to the Ditra handbook.

When to not use it? One thing I can think of is tile smaller than 2x2, which is in the handbook.

There are times I don't use it over a mud bed, and other times I do. It depends on the budget, and how important it is to have a fail proof job.

[Rkeister]

Robby -

The best way to look at the ditra is that if the subfloor isn't strong enough for backer, then it's not strong enough for ditra/vice versa. CBU has 0 structural value.

[Lump]

Robby, what Ditra will do for you is save your body from the abuse of backer board. Offer both options to your customers or choose the one that fits each job. You will not be disappointed transitioning to Ditra. Look into switching to Kerdi showers too you will never look back. good luck

[Hank B.]

Robby, your post seems to imply you consider your cement board as part of the sub floor? As mentioned, cement boards add no structural value. So if you have 3/4" plywood/osb, whether you use ditra, or 1/2" cbu you still only have a 3/4" sub floor.

Imo the only drawback to ditra is having to buy rolls that are 320 sq ft. vs cbu that can be purchased in 15 ft increments. But if you do a lot of tile over wood substrates then it's not a big deal. The other drawback is schluters requirement to use non modified thinset. But that isn't really a problem in my opinion. Plus lots of folks use modified anyway. You'll void your warrantee, but you don't get much of a warrantee with cbu anyway.

[talon4x4]

The ability to carry the underlayment for an entire job under 1 arm is a big plus to using Ditra.

I'm in the process of doing my first DIY'er bathroom remodel. I liked what I read about Ditra plus I figured after carrying sheets of plywood, drywall and 80lbs boxes of tile up to the 2nd floor, did I really want to carry cement board up there too.

[Eschbach]

I use Ditra over 3/4 ply and osb all the time.Use a good modified and check your coverage and you will be fine.Get a handbook and study the models.It is about a buck a foot and can be installed fast with scissors and a razor.Also you cant beat an 1/8 of an inch

[tilelayer]

Well schluter says you can put ditra over joists 24" on center as long as you add a layer of plywood, as far as I know you cannot do that with any other product...

[e3]

We also do it,had it tested years ago at the TCNA,nothing new.

[tileguynky]

Posted by Derrick,

Well schluter says you can put ditra over joists 24" on center as long as you add a layer of plywood, as far as I know you cannot do that with any other product...

Funny how some concrete board will give a track home builder a warranty on 24" OC without second layer of ply when the builder is still doing 400+ houses a year but won't give the warranty to me when I work in those same houses as people are remodeling the older houses.

As for the Ditra, it's my number one choice of underpayment. I usually don't even talk about concrete board. I buy it in the 320sq ft rolls because my local vendor gives a sweet discount for full roll purchase. They also sell it by the lineal foot, which is great for those doing small projects. I also buy my Kerdi in full rolls too, again huge price break when I do the full roll.

[cx]

Originally Posted by Derrick

Well schluter says you can put ditra over joists 24" on center as long as you add a layer of plywood, as far as I know you cannot do that with any other product...

In addition to what Eric said, I believe the TCNA publishes a couple methods (F149/155-12) of doing that with no membrane or other tiling substrate at all. And one for DensShield type products. And one for membranes such as Eric's.

[gueuzeman]

Originally Posted by original post

when should you NOT use Ditra.

When you REALLY need to save height, then use Greenskin.

Because there are times when you need to use 2 layers of plywood.

I use cement board for floor protection these days. Thats about it.

.

[NAI]

I've never used greenskin, only Schluter (Ditra/Kerdi) and Laticrete (Hydroban/Blue 92/9235). Each has is purpose/preference. Since i use laticrete 317 with ditra (usually install on concrete substrate) i want to try laticrete's new strata mat and see how that compares.

Also, you can try using laticrete 125 instead of a ditra/mat ... this works well, doesn't save on material costs, but a little in labor.

Either way, its just good practice. my problem is most DYI shows use ditra, so if you use something other than the 'orange' mat, clients think they are getting a subpar product ...

[MNTileGuy]

Ditra XL is rated for single layer ply on 24" oc floors.