Floors, Interior - Tile over Structural Plank Subfloor

• maximum spacing of joists is 24" (610 mm) o.c.
• double layer wood floor consisting of:
  - minimum structural plank subfloor thickness – 3/4" (19 mm)
  - minimum underlayment thickness – 15/32", 1/2" nom. (13 mm)

Substrate Preparation

• verify that subfloor planks are properly fastened to framing members
• underlayment – minimum 15/32", 1/2" nom. (13 mm)-thick eposure 1, plugged-face plywood or OSB with 1/8" (3 mm) gap between sheets;  
• any leveling of the assembly must be done prior to installing Schluter-DITRA

Movement Joints

• Schluter-DITRA does not eliminate the need for movement joints, including perimeter joints, within the tiled surface. Movement joints should be installed in accordance with industry standards and norms; see guidelines for the placement of movement joints for more details

Setting and Grouting Materials

• latex portland cement (p.c.) mortar - ANSI A118.11
• unmodified thin-set mortar - ANSI A118.1
• grout - ANSI A118.3, A118.6, A118.7, A118.8

Setting and Grouting Specifications

• tile - ANSI A108.5
• grout - ANSI A108.6, A108.9, A108.10

Other Considerations

• vapor barrier on crawl space floors according to regional building codes
• where a waterproof floor is required, all Schluter-DITRA seams and floor/wall transitions must be sealed with Schluter-KERDI-BAND using unmodified thin-set mortar; see waterproofing requirements for more details
• certain moisture-sensitive stones, e.g., green marble, or resin-backed tiles may require special setting materials. Consult stone supplier and Schluter®-Systems for more information