Deciding on constructing floors on soil, we should prepare a very thorough design, since it is a barrier that is constantly exposed to the presence of cold and dampness from the soil. A floor, in contrast to, e.g., a wall, is relatively difficult to dry and thus it has to not only be stable from the very beginning, but, most importantly, properly insulated. Otherwise, we are facing very costly and inconvenient renovation work. If we are also pressed for time and we want to accelerate the readiness of subsoil for laying concrete floors, then we have no choice but to use lightweight expanded clay aggregate.
Expanded clay is lighter than sand, much more stable and has excellent insulation parameters. It is also chemically inert, natural, non-flammable and frost-resistant. Furthermore, it is an exceptionally durable material, resistant to all kinds of moulds and rodents. Using it will greatly accelerate construction work, since a single layer of this material replaces three other layers. In this case these are the sand bedding layer, bottom layer of concrete sub-base and the thermal insulation material (wool or foamed polystyrene).
Floor on expanded clay is built in a very similar manner to traditional floor, with a bedding layer and foamed polystyrene/wool, only much quicker and more easily. You just need to lay the aggregate on soil. You can do this with loose aggregate, i.e. simply pour expanded clay on compacted soil, or you can also lay it directly in bags. In the first case, the laid aggregate layer should be properly compacted, e.g. with a lightweight mechanical compactor, and then covered with a thin stiffening layer of very thin concrete. It will be easier to lay damp-proof insulation and then the reinforcement and floor on such a layer.
If, for a change, we lay expanded clay directly in bags, then we do not compact it, but fill the empty spaces with loose aggregate and cut the bags open in order to remove excess air from them. We do not cover the bags with a layer of concrete, but lay the damp-proof insulation directly on them. Further work is the same as in the case of a traditional floor – reinforcement, expansion joints and concrete screed.
Thanks to the use of expanded clay aggregate, laying the floor will be faster and the subsoil underneath it will be prepared just as well, as in the case of work conducted in the traditional manner.