Basements built since 1980


How is a ground floor slab constructed?

Virtually every client will sooner or later be confronted with the topic of ground floor slabs. As a transition between the ground and the building, this component is essential in the construction of a basement. A distinction has to be made between non-load-bearing basement floor slabs and so-called ground floor slabs. The latter play an important role in the statics of the building.
When talking about a floor slab, people almost always mean a ground floor slab. But how is such a ground floor slab actually built? What are their advantages and what variants are there? In the following blog post, we will answer these questions.


Built according to a standardised scheme

In the construction industry, the floor slab conceals a slab-shaped foundation. It is considered the constructive and static basis of the transition between the structure and the ground. Floor slabs are the basic requirements for the comprehensive stability of the building and are always built according to a standardised scheme. This includes the founding, the drainage (including laying the drainage pipes), the insertion of the spacers, the sheathing and laying of the reinforcement and finally the concreting. In addition to floor slabs in the form of foundation slabs, there are also strip foundations (e.g. for individual walls) as well as point foundations for support columns.

The individual steps in the floor tile construction

The construction of a floor slab is done in five steps:

  1. The founding (shallow foundation / deep foundation)
    Depending on the subsoil, the first decision is which type of foundation to use. It must be different on a hillside than on a plain. Important: Frost protection must be guaranteed to a depth of at least 80 cm. This is the only way to prevent damage at a later date.

  2. The drainage
    The next step is laying the hard, plastic underground pipes for sewage, rainwater, etc. Also, PVC ducts are installed into the ground under the floor slab for access to Gas, Electricity, Telecoms etc. Lifting systems and backflow valves are also installed in this phase. After the pipes and ducts are installed, a shingle and gravel filling is used and  a special PE foil is installed.

    Bodenplatte Entwässerung + MSH

  3. Formwork and installation of the spacers
    After inserting a special PE foil as a separating layer underneath the ground bearing slab, spacers are installed to maintain the concrete cover and to guarantee the long-lasting durability of the building above.

  4. The reinforcement
    Before concreting the floor slab, reinforced steel is installed.

  5. The concreting
    The last step is the concreting. Here, C20 / 25  grade concrete is used. The concrete is compacted by specialised machinery, which then smooths the surface. The rate at which the concrete hardens depends on the surrounding temperature and the air pressure. In normal conditions, this takes around 28 days. As soon as the minimum pressure capability has been reached, it’s possible to start building the house.

    Bodenplatte Betonage

Various floor plates are available

Glatthaar Fertigkeller offers two types of floor slabs: the Vario and the EcoHit. The difference lies in the type of frost protection offered. While the Vario floor slab is considered to be the ideal solution for level building sites, EcoHit floor slabs are used on sloped building plots or on poor ground conditions. As the standard Glatthaar ground bearing slab, the frost protection on Vario floor panels is achieved with a surrounding layer of concrete, whereas the frost protection on the EcoHit panel is ensured by a frost-resistant substrate.

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