My head is spinning over the different answers I am getting about mortar;

We took a very long time but we finally have our heated flooring in the bathroom covered with Self leveling compound. We wanted to use Ditra over this but we are confused on what type of mortar. Some say modified some say unmodified, some say modified under and unmodified over to lay tiles. We are seconds away from laying tiles but we want to do it right. Please help me do it right.

It looks like we are going with Kerabond Premium Grade Dry Set Mortar for both sides of the Ditra. I hope its right.

It's really pretty simple. Unmodified to set your tile on Ditra, always. Underneath, you use unmodified if setting to concrete (including cement boards or self leveling cements or mud beds) or use modified underneath if setting onto plywood.

Use gray underneath as you will get a very contrasting darkening of the Ditra as you embed the fleece into the mortar so you will be sure of the coverage underneath.

Better quality unmodified thinsets, which are those you want to use, will start in the $10-$11 dollar range. Low budget unmodifieds, while scraping the minimum standards of ANSI 118.1 should be avoided. Stay away from the entry level $5-6/50 lb bag stuff.

In your case, specifically use unmodifed under and above and be certain to scrape the back of each tile with the thinset before you set it to ensure complete contact of the unmodified thinset with every little pore and nook on the back of your tile.

Good Luck.

I just saw your answer Bljack. Thank you so much. It looks like we picked the right choice. I was told Kerabond was very good.

Kerabond is a very good choice. For anyone else, other decent unmodifieds include Laticrete 317 (aka "megabond" through Lowe's stores), Tec's Full set plus (I'm not a fan of Tec's Sturdiset on it's own), and for those that have Hydroment products around them, you might be able to pick up a bag of Ditraset, but if not, either Tilemate or Tilemate Premium. No one near me carries c-cure so no suggestions there. Ironic that Home Depot has Ditra in stock and can order Kerdi but the only unmod they have or can get is Custom Blend, far from a premium variety. Custom building products used to sell masterblend, decent product. If you find it somewhere now, it's far past it's usable date. Maybe Jaz can also comment on some of the other unmods for the lurkers who research but never post.

You pretty much covered the subject Brian. I use Ditraset or Laticrete 317 when ever setting over Ditra and when building Kerdi showers. I'm open to also using Tec's Full Set Plus and even others with the exception of the cheap Custom's mortar sold at the orange place.

My Schluter distributor also distributes Laticrete and Hydroment products so I'm lucky in that regard. If I run short I'll run into a Lowe's for Megabond as you also suggested.

Jaz