What should a foundation slab be made of to eliminate the undesirable phenomenon of floor settling while effectively insulating it? What material should be chosen in the case of complicated soil conditions when it is important to maximally relieve the structure? We have the answers!
The advantages of using foundation slabs are numerous, which is why not only investors planning to build on difficult soils (light, waterlogged, unstable) opt for this solution. In the cases mentioned above, a foundation slab distributes the loads much better than traditional foundations, thus solving the problem of building settlement. However, nothing prevents choosing a slab instead of traditional strip foundations even on soils with good bearing capacity. This solution significantly speeds up the construction time and can often be much cheaper than heavy, labor-intensive, and costly foundations. A well-prepared and level foundation slab is a surface ready for laying the floor, eliminating the need for building a floor on the ground. Additionally, underfloor heating can be installed in the slab, and the fact that it is insulated from the ground over the entire surface (not just around the building perimeter like strip foundations) effectively eliminates thermal bridges. Therefore, investors building energy-efficient or passive houses often choose a foundation slab. Various types of foundation slabs are available on the market: reinforced concrete, concrete, or slabs made of prefabricated elements. In this article, we explain why it is worth choosing foundation slabs made of foam concrete.
Foundation Slab Made of Poured Cellular Concrete
Why is foamed cellular concrete particularly suitable for foundation slabs? As mentioned earlier, it helps to relieve the structure, thus mitigating settlement phenomena – this is fundamental, but not the only reason. This material also has excellent thermal insulation properties – 20 cm of foam concrete is equivalent to 10 cm of styrofoam. The ability to forgo styrofoam is invaluable as it eliminates the risk of deformation, disappearance, and eventual floor settling over time or due to even small fires or aggressive chemicals. In a floor made of poured cellular concrete, there are no spaces where rodents or insects could nest. Moreover, floors insulated with styrofoam create a resonance box effect – they tend to boom when walked on. This problem does not occur with poured foundation slabs. Another great advantage is the ease and speed of construction – the material is delivered through hoses up to 100 meters, eliminating the need for heavy equipment on the site. This method allows for quick execution. A foundation slab made of foamed cellular concrete is poured in one day. Combined with one day for earthworks, laying the PE film and any necessary formwork, and one day for formwork, reinforcement, and pouring the reinforced concrete slab, all work takes only three working days in total.
The material, which is poured cellular concrete, perfectly secures all installations, pipes, and cables embedded in the slab by surrounding, stiffening, and protecting them from movement and leakage. The resulting structure is uniform, monolithic, and free from thermal bridges, and it does not require expansion joints. A foundation slab made of foam concrete is essentially a ready-made floor. Therefore, there is no need to transport and compact sand, perform additional insulation, or use so-called lean concrete and styrofoam, which is a non-load-bearing material – its disappearance and settling are only a matter of time. Cellular concrete has a much higher compressive strength, making it suitable for very demanding projects, such as the construction of roads, highways, airports, and parking lots.
Example of a Foundation Slab Construction
- Reinforced concrete slab (10 cm)
- Insulation layer of foam concrete PB 500 (50 cm)
- Insulation foil
Foam concrete, or foamed cellular concrete, is one of the most modern methods for building foundations, especially when they are to be built on difficult soils. This technology came to Poland from the Netherlands – a country where nearly 80% of the land consists of non-load-bearing soils. There, foam concrete is commonly used because it helps to relieve building structures while maintaining good strength and thermal insulation properties.