DITRA Installation Instructions

For centuries, builders have relied upon the uncoupling principle to lay tile. Unlike today's direct bond installations in which tile is bonded directly to the substrate, an uncoupled installation allows independent movement between the tile covering and the substrate, neutralizing differential movement stresses between the substrate and tile covering. This is particularly important with the use of today's thinner, larger-format tiles and lightweight building materials.

Easy Step-by-step installation

1. Using a thin-set mortar that is suitable for the substrate, apply the thin-set mortar (mixed to a fairly fluid consistency, but still able to hold a notch) using a 1/4" x 3/16" (6 mm x 5 mm) or 5/16" x 5/16" (8 mm x 8 mm) V-notched trowel.

2. Apply Schluter-DITRA to the floor, fleece side down. Work DITRA into the mortar, using a float or screed trowel in such a way that the fleece of the DITRA is solidly embedded in the bonding mortar throughout its entire surface (please observe the open time of the bonding mortar).  After applying DITRA, lift up one corner to check the fleece for full mortar coverage. For joining sections of DITRA, simply abut end and side sections of adjacent sheets.

3. Tile can be installed over Schluter-DITRA immediately; no need to wait for the mortar to cure. Using a trowel that is appropriate for the size of the tile, apply the bonding mortar (unmodified thin-set mortar) and solidly embed the tiles in the setting material. Periodically remove and check a tile to assure that full coverage is being attained.

Estimated thin-set coverage:

• To bond DITRA to the substrate:   Use one 50-lb. (22.68 kg) bag of mortar per 150 - 200 sq ft (13.9 - 18.6 sq m).

• To bond the tile to the DITRA:  Using a 1/4" x 3/8" (6 mm x 10 mm) square- or U-notched trowel will require 50-lb (22.68 kg) bag of mortar per 40 - 50 sq ft (3.7 - 4.6 sq m).

Waterproofing

The following steps are required for waterproofing only.  This practice is not required in all applications, but provides for a waterproof installation that will not suffer damage in the event of an unexpected water leak (e.g.: overflowed toilet, broken dishwasher line, etc.).

1. At the joints, fill the cut-back cavities with unmodified thin-set mortar, approximately 8" (203 mm) wide, centered over the joint.
   
   
2. Comb additional unmodified thin-set mortar over the joint using a 1/4" x 3/16" (6 mm x 5 mm) V-notched trowel.
   
   
3. Using the flat side of the trowel, firmly press the 5" (127 mm) wide Schluter-KERDI-BAND into the mortar to ensure 100% coverage and to remove excess mortar and air pockets.
   
   
4. At all wall junctions, apply a 10" (254 mm) wide strip of Schluter-KERDI-BAND, centered where the wall and floor meet. 

Notes:

• KERDI-BAND must lap DITRA at seams and at floor/wall transitions by a minimum of 2" (50 mm) in order to maintain waterproof integrity. 
  
  
• In some applications the vertical section of the floor/wall transition will not accept a bond to unmodified thin-set mortar. Connections to such elements can be achieved using Schluter-KERDI-FIX or suitable trowel-applied waterproofing materials, such as those that require atmospheric moisture to cure (e.g., urethane sealant).