Gypsum Substrate

Schluter-DITRA and Schluter-DITRA-XL

Specifically designed as an underlayment for ceramic and stone tile

Ceramic and stone tiles are durable, easy to maintain, and hygienic, representing the ideal surface coverings. However, today’s lightweight construction methods can make the installation of hard surface coverings particularly challenging. In order to protect the integrity of the tile assembly, an underlayment that performs multiple functions is required.

Schluter-DITRA and Schluter-DITRA-XL are specifically designed to allow the installation of ceramic and stone tile over any even and load-bearing substrate. The integration of four functions—uncoupling, waterproofing, load-distribution, and vapor management—makes consistent results viable through the use of Schluter-DITRA or DITRA-XL.

Every substrate presents unique challenges

Bonding ceramic or stone tiles directly to gypsum concrete substrates is generally considered questionable or not recommended. The challenges associated with gypsum-based underlayments include the requirement of an extended drying period before installing tile and continued sensitivity to the reintroduction of moisture throughout the life of the installation.

In addition, since the coefficient of thermal expansion of gypsum concrete is substantially greater than that of ceramic tile, shear stresses caused by temperature fluctuations can result in delamination or cracking of the tile covering. This is particularly important when gypsum concrete is used as a thermal mass for radiant heated floors. With the increasing popularity of radiant heated floors, which typically utilize gypsum concrete, tile installers need a reliable installation system to address these issues.

Uncoupling

Schluter-DITRA/ Schluter-DITRA-XL’s uncoupling function protects the ceramic or stone tile covering by neutralizing the differential movement stresses between the gypsum concrete substrate and the tile, thus eliminating the major cause of cracking and delaminating of the tiled surface.

Waterproofing

Schluter-DITRA/ Schluter-DITRA-XL’s waterproofing function prevents the reintroduction of moisture to gypsum concrete underlayments, which, if not prevented, could significantly compromise performance of the underlayment and lead to damage of the tiled surface.

Vapor Management

The residual moisture in gypsum concrete is allowed to escape through the channels on the underside of the Schluter-DITRA or Schluter-DITRA-XL matting. This is particularly important since gypsum concrete must dry in order to gain strength.

Support/ Load Distribution

Since Schluter-DITRA and Schluter-DITRA-XL are virtually incompressible within the tile assembly, the advantages of uncoupling are achieved without sacrificing point load distribution capabilities.

By addressing all of the challenges associated with today’s fast, lightweight construction methods, Schluter-DITRA and Schluter-DITRA-XL provide a durable installation system for ceramic and stone tile over gypsum substrates.