1. The substrate must be free of bondinhibiting components, load bearing, and even. Any unevenness in the substrate must be levelled prior to the application of Ditra.
2. The type of bonding adhesive used to apply Ditra depends on the type of substrate. The adhesive must bond to the substrate and mechanically anchor the fleese on the underside of the Ditra matting. Verify the compatability of all materials prior to installation.
3. Apllt the bonding adhesive to the substrate using a 3x3mm or 4x4mm notched trowel.
4. Intervidual courses of Ditra are cut to size. Solidly embed the anchoring fleese on the underside of the Ditra in the adhesive so that its entire surface is bonded, and immediatly work into the adhesive a float or screed trowel. Please observe the open time of the bonding adhesive. When initially positioning Ditra, it is advisable to align and position the matting while slightly stretching it.
Application is made easier with a second person. The side edges and ends of individual courses are cut straight and abutted.
Note: If Ditra is only installed as an uncoupling membrane, side edges and ends of indervidual courses do not need to be sealed with Schluter -KERDI-KEBA. Please refer to the instructions for waterproofing.
5. Once installed, the matting must be protected against heavy mechanical loads to avoid loosening it from the substrate or other damage. It is advisable to place running boards to protect the Ditra. Other protective measures, such as sheilding of direct sunlight or protection from precipitation in exterior applications, may also be required. Carefully remove any moisture that may have gathered in the indentations of the studs before applying the thin-bed adhesive.
6. Immediately after the Ditra matting is installed, the tiles can be set using the thin bed method and using a bonding tile adhesive that matches the requirements of the covering. It is recommended to fill the square cavities with the smooth side of the trowel and to establish a regular pattern in the tile adhesive with the notched side of the trowel in one application. The tiles are fully embedded in the adhesive. The notches must mtch the thickness of the tiles.

could I lay DITRA matting directly on to old tiles and then put new tiles on top?

Originally Posted by Branleur

could I lay DITRA matting directly on to old tiles and then put new tiles on top?

I wouldn't advise it,take the tiles up.

Originally Posted by Dylante

1. The substrate must be free of bondinhibiting components, load bearing, and even. Any unevenness in the substrate must be levelled prior to the application of Ditra.
2. The type of bonding adhesive used to apply Ditra depends on the type of substrate. The adhesive must bond to the substrate and mechanically anchor the fleese on the underside of the Ditra matting. Verify the compatability of all materials prior to installation.
3. Apllt the bonding adhesive to the substrate using a 3x3mm or 4x4mm notched trowel.
4. Intervidual courses of Ditra are cut to size. Solidly embed the anchoring fleese on the underside of the Ditra in the adhesive so that its entire surface is bonded, and immediatly work into the adhesive a float or screed trowel. Please observe the open time of the bonding adhesive. When initially positioning Ditra, it is advisable to align and position the matting while slightly stretching it.
Application is made easier with a second person. The side edges and ends of individual courses are cut straight and abutted.
Note: If Ditra is only installed as an uncoupling membrane, side edges and ends of indervidual courses do not need to be sealed with Schluter -KERDI-KEBA. Please refer to the instructions for waterproofing.
5. Once installed, the matting must be protected against heavy mechanical loads to avoid loosening it from the substrate or other damage. It is advisable to place running boards to protect the Ditra. Other protective measures, such as sheilding of direct sunlight or protection from precipitation in exterior applications, may also be required. Carefully remove any moisture that may have gathered in the indentations of the studs before applying the thin-bed adhesive.
6. Immediately after the Ditra matting is installed, the tiles can be set using the thin bed method and using a bonding tile adhesive that matches the requirements of the covering. It is recommended to fill the square cavities with the smooth side of the trowel and to establish a regular pattern in the tile adhesive with the notched side of the trowel in one application. The tiles are fully embedded in the adhesive. The notches must mtch the thickness of the tiles.

Ditra should be cut to mirror any existing movement joints, and also cut where additional movement joints are to be placed