Floating slabs are concrete slabs that are laying over the ground, without any kind of anchoring, as if it simply sits on it and floats. Floating slab, as the name tells it resembles a plate that is simply laid over water, with no kind of connection between them.
It is economical when used in areas wherever the need for standard foundations is not required. The main application of floating slabs is to use as a base foundation for sheds, manufacturing workshops, home additional room, or garages. The construction details are explained in detail in the following sections.
When we assume a building with floating arrangement, we must picturize as a building with a standard foundation of strip footing, that is constructed several feet below the ground. Then we have the wall built up above the ground surface. Then literally the floating slabs float on the ground. Here the need for ground preparation is reduced to a larger extent.
The floating slabs are called as monolithic slabs as they have no connection with the foundation. If it’s the case, only after curing of the foundation we cast the floating slab.
The building of floating slabs needs details to start the proposed building needs a solid foundation to completely support the whole weight of superstructure.
These buildings are light in structure. So floating slabs are found most suitable and economical, compared with conventional slab building. As mentioned they are more used in garages, an extension of the house or sheds that does not necessarily need huge foundations.
The main construction layers in the floating slab are shown in figure-1. The construction involves the following steps:
Fig.1: Floating Slab Layers
The initial stage of floating slab building is to clear the land and excavate the area as per the plan. This is the initial preparation for the building.
Fig.2: Preparation of land by removing the upper layer
The step also involves making a drainage in the sides, for the water to drain out through the gravel base as shown below. The trench constructed is sealed with geotextile and gravels as shown below, which will remove water from concrete slab foundation as shown in figure 3.
Fig.3: Excavated drainage and the prepared drainage
Fig.4: Laying Gravel base layer over the area for drainage of unwanted water
The slab mold is placed for casting process. To strengthen the slab, the reinforcing bars are provided as per dimensions and codes.
Fig. 5: Reinforcement Bars Arranged in slabs
It is compacted either my labor or mechanical vibrator depending on the area and workmanship. The concrete is poured into the slab formwork. Proper curing has to undergone for almost 2 to 3 days. Proper compaction has to be undergone, to make the slab fully productive.
Fig.6: Compaction of Poured Concrete