Prior to installation, it should be verified whether the installation sub-layer is suitably prepared. This means that the sub-floor must be dry, even, clean and able to provide a supporting surface. Suitable sub-layers are all types of screed including hot water-heated screed, wooden chipboard structures, fibreboard, PVC, linoleum, natural stone boards or ceramic tiles.
The sub-floor must be dry, able to support loads, even, and clean. Large deviations should be handled with suitable measures (e.g., with self-levelling compounds).
For more information, please see the relevant Fitting Guide.