Schlüter^®-DITRA 25 is a polyethene membrane with a grid structure of square cavities, each cut back in a dovetail configuration and an anchoring fleece laminated to its underside. Designed for tile and natural stone installations, Schlüter^®-DITRA 25 serves as a waterproofing membrane, a vapour pressure equalisation layer to accommodate construction moisture occurring within the substrate and an uncoupling layer for problematic substrates.

The substrate must be even and load-bearing. To bond Schlüter^®-DITRA 25, use a bonding adhesive that is appropriate for the substrate. Apply the adhesive using a 3 x 3 mm or 4 x 4 mm notched trowel. The anchoring fleece on the underside of Schlüter^®-DITRA 25 must be fully engaged in the adhesive to provide a mechanical bond to the substrate. Please observe the open time of the bonding adhesive.

Using the thin-bed method and following all applicable industry standards, set the tile or stone covering directly on the Schlüter^®– DITRA 25 in such a way that the tile adhesive becomes mechanically anchored in the square, cut back cavities of the Schlüter^®– DITRA 25 matting.

Functions

Uncoupling
Schlüter^®-DITRA 25 uncouples the floor covering from the substrate and neutralises the tensions between the substrate and the tile covering that result from the varying deformations of the materials. Likewise, stress cracks in the substrate are bridged and are, therefore, not transferred to the surface covering.

Waterproofing
Schlüter^®-DITRA 25 is a waterproof polyethene membrane with a relatively high vapour diffusion density. Provided the mat joints and the connections to walls and built-in elements are properly installed, Schlüter^®-DITRA 25 can be used to create a certified bonded waterproofing assembly with the tile covering. Schlüter^®-DITRA 25 features the national technical approval (abP) required in Germany and bears the Ü mark. Moisture exposure class according to abP: 0 – B0 as well as A and C.
Schlüter^®-DITRA 25 has the required European Technical Assessment (ETA) as specified in ETAG 022 (bonded waterproofing assemblies) and bears CE marking.
Exclusively use system-approved thin-bed adhesives for areas that require CE conformity or compliance with the general certificate of national technical approval (abP). Please contact us at the address shown in this data sheet for further information about suitable thin-bed adhesives and the corresponding test certificates.
Therefore, Schlüter^®-DITRA 25 protects the substrate against damage due to moisture penetration and aggressive substances.

Equalisation of vapour pressure
The interconnected air channels between the cavities on the underside of the Schlüter^®-DITRA 25 matting remain open. This allows moisture in the substrate to evaporate, therefore neutralising vapour pressure.

Load distribution (load impact)
Tiles that are installed in floor coverings with Schlüter^®-DITRA 25 should have a minimum size of 5 x 5 cm and be at least 5.5 mm thick. The bottom of the square cavities in Schlüter^®-DITRA 25, which are filled with thin-bed adhesive, directly transfer the load impact on the tile covering to the substrate. As a consequence, tile coverings installed on top of Schlüter^®-DITRA 25 are highly load resistant. If high traffic loads are expected (e.g. in industrial locations), the tiles selected for the installation must be of the corresponding thickness and pressure stability. The requirements of the mandatory guideline “Ceramic Floor Coverings With High Impact Resistance,” published by the German Construction Industry Association (ZDB) must be followed.
In areas with high impact loads, the tiles must be fully embedded in the thin-bed adhesive. The contact surface of Schlüter^®– DITRA 25 amounts to approximately 50% of the total surface. This can reduce the load-bearing capacity in case of point loads. For high point loads, select a tile thickness that is capable of distributing the loads. Ceramic tile coverings should not be exposed to the direct impact of hard objects.

Adhesive properties
Due to the bonding of the anchoring fleece into the thin-bed adhesive on the underside and the mechanical anchoring of the adhesive in the cut back cavities, Schlüter^®-DITRA 25 achieves a good adhesion of the tile covering to the substrate (laboratory test values: ~ 0.2N/mm²). Consequently, Schlüter^®-DITRA 25 can be used for wall and floor coverings. Anchor plugs may be used with wall coverings if necessary.