Heated Floors, Interior - Tile or Stone

Wood Substrate - thin-mat or wire system

Areas of Application

  • over an even ad structurally sound substrate
  • interior dry or wet areas according to heating system manufacturer's recommendations


  • minimum 2" x 2" (50 mm x 50 mm) tile


*** Essential
**   Significant
*     Helpful


  • for wood substrates, subfloor/underlayment configuration according to details for 16" (406 mm) o.c. joist spacing 19.2" (488 mm) o.c. joist spacing 24" (610 mm) o.c. joist spacingNatural Stone

Substrate preparation

  • any leveling of the assembly must be done prior to installing Schluter-DITRA and Schluter-DITRA-XL
  • additional preparation according to the manufacturer's directions

Movement Joints

  • Schluter-DITRA and Schluter-DITRA-XL do 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
  • heating system – follow manufacturer’s directions

Other Considerations

  • vapor barrier on crawl space floors according to regional building codes 
  • where a waterproof floor is required, all Schluter-DITRA and 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
  • 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

open/close   Further information
open/close   Download DITRA Installation Handbook
open/close   Download Ditra Installation Information