24” (610 mm) o.c. joist spacing, single layer OSB or plywood subfloor

Areas of Application

  • over any even and structurally sound OSB or plywood subfloor with 24" (610 mm) o.c. joist spacing
  • interior dry or wet areas



*** Essential
**   Significant
*     Helpful


  • maximum spacing of I-joists or floor trusses is 24" (610 mm) o.c.
  • minimum subfloor thickness - 23/32", 3/4" nom. (19 mm) tongue-and-groove with 1/8" (3 mm) gap between sheets

Substrate Preparation

  • verify that subfloor panels are properly fastened to framing members 
  • any leveling of the assembly must be done prior to installing Schluter-DITRA-XL

Movement Joints

  • Schluter-DITRA-XL 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

  • tightly butted and/or tented plywood or OSB seams must be addressed prior to installing Schluter-DITRA-XL
  • vapor barrier on crawl space floors according to regional building codes
  • where a waterproof floor is required, all Schluter-DITRA-XL seams and floor/wall transitions must be sealed with Schluter-KERDI-BAND using unmodified thin-set mortar; see waterproofing requirements for more details