Any floor, before laying the base coat, needs a screed that will allow the finish coat to lie flat. Recently, a semi-dry floor screed has been quite often used, for more details see https://altpol.ru/luchshaya-styazhka-polov/. The implementation of a screed using this technology differs slightly from concrete and is considered more complicated.
The solution is prepared from almost all the ingredients that are used with a concrete screed (cement, sand, in some cases plasticizers and expanded clay), but less water must be added to make it semi-dry. The peculiarities of the technology lie in the absence of the use of a reinforcing mesh, instead of which a relatively new material is used - fiber. Unlike metal reinforcing mesh, fiberglass will not rust, decompose or lose its technical properties over time, which is very important for the environmental friendliness and durability of the final floor covering.
The bases under the screed are primed to increase adhesion, after which the fiberglass is laid. A solution is poured on top, leveled and carefully tamped. Such a screed dries much faster than a concrete one, due to the smaller amount of water in its composition. After two weeks, it will be possible to lay the main flooring material on its surface.
By the way, a semi-dry screed can also be used over concrete, if the latter is damaged or initially uneven. Features of performing a semi-dry screed are presented in the video
