Introduction
Schluter®-DITRA is an underlayment for ceramic and stone tile installations, offering uncoupling, waterproofing, vapor management, and support/load distribution. It is suitable for various substrates and applications.

Installation Guidelines
Schluter®-DITRA can be installed over wood, concrete, gypsum, and heated floors. It requires specific thin-set mortars and adherence to movement joint guidelines.

DITRA-XL
A thicker version designed for even transitions between tile and hardwood flooring, accommodating greater movement and supporting installations over single-layer wood subfloors with wider joist spacing.

Testing and Certifications
DITRA and DITRA-XL have undergone extensive testing, including ASTM C627, to ensure performance under various conditions.

Specifications
Schluter®-DITRA and DITRA-XL are used for waterproof flooring applications. Seams and floor/wall transitions must be sealed with Schluter®-KERDI-BAND using unmodified thin-set mortar. Applicable over OSB or plywood subfloors with joist spacing up to 24" (610 mm) o.c. Minimum tile size is 2" x 2" (50 mm x 50 mm).

Substrate Preparation
Ensure subfloor panels are properly fastened. Underlayment should be a minimum of 11/32", 3/8" nom. (10 mm) thick, with a 1/8" (3 mm) gap between sheets. Leveling must be done prior to installation.

Movement Joints
Necessary and must comply with industry standards (TCA EJ171, TTMAC 301 MJ).

Setting and Grouting Materials
Use latex portland cement (p.c.) mortar (ANSI A118.11) and unmodified thin-set mortar (ANSI A118.1). Grout should comply with ANSI A118.3, A118.6, A118.7, A118.8.

Applications
Applicable for interior dry or wet areas, over structural plank subfloors, and existing vinyl floors. For concrete subfloors, Schluter®-DITRA provides uncoupling and waterproofing, protecting against differential movement stresses.

Limitations
Minimum tile size is 2" x 2" (50 mm x 50 mm). For natural stone, specific details and discussions are required. Concrete slabs must be structurally sound and free of waxy or oily films.

Other Considerations
Moisture-sensitive stones may require special setting materials. Vapor barriers are necessary on crawl space floors according to regional codes. Schluter®-DITRA's uncoupling function is beneficial for installations over concrete, addressing challenges like thermal expansion and moisture migration.

Exterior Applications
Concrete Substrate - Over Unoccupied Space: Provides waterproofing and allows moisture to escape from the substrate.
Wood Substrate - Over Unoccupied Space: Requires a sufficient slope (1.5 - 2%) and exterior-grade subfloor panels.
Concrete or Wood Substrate - Over Occupied Space: Requires specific subfloor/underlayment configurations and a roofing membrane with sufficient slope.

Movement Joints
Essential in tile assemblies to accommodate differential expansion and contraction of components due to changes in moisture, temperature, and loading.

Technical Guidelines
Movement joints are crucial in tile installations to accommodate movements and prevent stress-related damage. Schluter®-Systems offers prefabricated movement joint profiles, such as Schluter®-DILEX, which protect tile edges and prevent sound bridges and water penetration.

Testing and Performance
Unmodified mortars were tested for bonding porcelain tiles to DITRA over plywood, showing adequate performance. Freeze/thaw tests showed more than adequate performance without requiring extended drying times.

Green Building and VOC Emissions
Schluter®-DITRA emits zero VOCs, contributing to green building credits such as LEED and CHPS.

Warranty Information
Schluter Systems offers a 5-year limited warranty for Schluter®-DITRA and Schluter®-DITRA-XL, ensuring they meet composition and performance criteria when installed according to the Schluter®-DITRA Installation Handbook and industry standards.