Does the Staenis grid replace an uncoupling mat?

Yes, the Staenis grid divides the screed into areas of 0.5 x 0.5 m. This distributes the saucer-shaped effect and is expressed at least per square. In this way, the screed remains supported on the substrate and the tiles or floor finish do not experience any stress, making a decoupling mat superfluous, because the problem is solved at source in this way.