**1. Introduction**

Currently, floors are commonly made of cement-based materials. They are used in civil engineering for various purposes, e.g., as the top layer of the floor in residential and industrial buildings, in public buildings, and in multi-car garages [1]. Floors made of cement-based materials can also be a substrate for the finishing layer of other materials, such as epoxy resin coatings, ceramic tiles, parquet, etc. [2–4]. The substrate for floors is usually concrete or a reinforced concrete ceiling, but can also often be foamed polystyrene, which is a layer of thermal or sound insulation, which was presented in Figure 1.

In order to make floors made of cement-based materials without faults, it is necessary to comply with the technological and technical requirements that are contained in the standards and set by the designer [5–10]. However, this is not the only condition that needs to be met. It is first necessary to ensure by the technical supervision that the conditions necessary to make a decision about the commencement of flooring are met, and then to monitor the entire implementation process on an ongoing basis. In the final phase, strength requirements should be checked before the floor is commissioned. It should be stated that in the case of strength parameters, not only the flexural and compressive strength should be monitored. It should also test the compressive strength along the thickness of the floor. The non-destructive ultrasonic method with the use of exponential heads is irreplaceable for this purpose. Ultrasounds are still very popular in civil engineering (for example for damage detection, as presented in [11]). The problem of lower compressive strength in the upper zone of floors, which is related to the horizontal direction of their concreting, is described, among others, in [12,13]. The subsurface tensile strength and abrasion resistance should also be controlled, which depends on the compressive strength in the upper zone of the floor. This upper zone of the floor is, after all, subjected to direct operational effects, and therefore maintaining an adequate compressive strength and subsurface tensile strength in this particular zone is very important for durability and

safety of use [14–17]. This is very important when the floor is the final finishing layer. If the floor is laid directly on a concrete substrate or a reinforced concrete ceiling, the pull-off adhesion between the floor and the substrate also requires control, which is due to the fact that the durability of the exploited floor is dependent on this parameter [18–20].

**Figure 1.** Applied variants of various floor systems made on: (**a**) a concrete substrate or a reinforced concrete ceiling: (**b**) a foamed polystyrene laid on a concrete substrate or reinforced concrete ceiling.

In order for the entire flooring process to be correct, its control should be effective. Comprehensive control can guarantee this. This control should be complex and methodological. However, such a methodology is missing in the literature. According to the authors, the consequence of this can be seen in the very frequent cases of cement floors being executed badly, regardless of whether they are made of ready-mix cement mortars or prepared directly at the construction site [21–24]. In construction practice, there are known cases of removing defective floors and then re-executing them again [25–29].

Considering the above, the main goal assumed in this article is to develop—based on many years of experience acquired by the authors when testing the technical condition of floors, the quality of which has been questioned by users—an original and complex methodology for the effective control of the entire process of executing floors made of cement-based materials. The developed methodology is preceded in the article by a list of more important requirements for such floors. These are not only the result of a failure to comply with the relevant requirements, but above all the incorrect control of this technological process, which can be seen to be unmethodical, ineffective and not random. The article has been enriched with a discussion comparing and contrasting the current state and standards of quality control of floor performance with comprehensive control of the developed methodology. Its purpose is to show that the practical application of the proposed methodology will effectively eliminate many implementation problems and thus improve the quality of floors made of cement-based materials.
