What Is Floating Slab?
A floating slab is another type of concrete slab laid on the ground with no support. The slab is built in two stages. Footings are cast individually in the first stage, and then the center floor of the slab is poured.
Because of the floating slabs, the ground preparation is reduced to a larger extent. Since the floating slab does not have a connection with the foundation, it is also called a monolithic slab.
This type of slab is used when the structure requires low bearing capacity. This foundation is suitable for small structures where a deeper structure is not required and when additional infrastructure is not needed.
Floating slabs are used as the foundation for small structures such as manufacturing workshops, sheds, and garages. Let’s discuss its construction process.
Why Use Floating Slab?
Floating slab is one of the most economical foundation construction methods. Traditional foundations require a strip footing with a frost wall above. The strip footing installed below the frost level is usually 4 inches below grade. The cost of a strip footing and frost wall is higher because more excavation, concrete, and labor are required.
Construction Procedure Of Floating Slab
To begin the construction of floating slabs, the planned building requires a stable foundation to completely sustain the entire weight of the superstructure.
As previously said, they are more commonly utilized in garages, home additions, and sheds that do not require large foundations. Structure-wise, these structures are light.
When compared to conventional slab construction, floating slabs are proven to be the most suited and cost-effective. The steps involved in the construction of a floating slab are described below.
1. Site preparation
The first step is to inspect the site where the floating slab will be built. Clear the site of any trees, small shrubs, or other debris. Then, make an excavation plan, including where to dig and where to take the soil.
2. Excavation
After all the preparation, the next step is to excavate the site. Excavate the area for the slab in accordance with the level. In this step, make a drainage channel on the sides for water to drain out through the gravel base.
Water will be removed from the concrete slab foundation by sealing the trench with geotextile and gravel. Make sure to cover this channel with waterproofing material.
3. Laying Gravel Base
In this step, gravel is spread over the area to allow unwanted water to drain.
4. Reinforcement For Slab
After laying the gravel base, the next step is to prepare reinforcement as per the structural design. Lapping should not occur in a single location during reinforcement; instead, it should occur in a different manner.
In addition, the reinforcement must be in accordance with the slab’s dimensions and specifications in order to strengthen the structure.
5. Shuttering
Now, it is time to begin shuttering. The formwork may require a smooth surface, proper alignment, and good quality work. To prevent the formwork from opening during concrete pouring, the cover block should be fixed after shuttering.
6. Concreting
Concrete can be made on-site in a concrete mixer, or ready-mixed concrete can be used for floating slab concreting. All materials are mixed in a proper mixer machine to achieve high strength.
Adequate compaction should be performed during the concreting process. Depending on the area and workmanship, it is compacted by hand or by a mechanical vibrator. After 24 hours, the shuttering should be removed.
7. Curing
The slab should be cured for seven days after removing the shuttering. Curing plays an important role in achieving the desired concrete strength. For curing, water is sprayed.
Advantages Of Floating Slab
• A floating slab can keep moisture out of the floor. It is used to separate the ground and the superstructure. Additionally, it protects against water and frost.
• This slab has the spreading property, which allows vertical loads or stresses to be distributed over a larger area.
• A floating slab is a good option if your home requires an extension. This slab serves as a physical barrier between the superstructure and the ground. This prevents water and frosting. As a result, this slab is mostly used in cold-weather construction.
• Don’t require a wood flooring system & 8′-0″ basement wall.
• It requires less concrete and formwork for more economical and ecological construction.
• No footer trenches are required for this slab. They can be poured by trenching or excavating, which is a less expensive method. This slab causes no disturbance to the earth beneath it.
• Floating slabs can be heated with radiant floor heat, which provides a comfortable and balanced heat.
• Floating slabs are the best choice where the soil layer has a chance of shifting, primarily because of high moisture content.
• Cheaper house insurance because there is no basement to flood or chance of Radon gas infiltration.
Disadvantages Of Floating Slab
• It uses outdated technology.
• Less design resonance exists in foundations with floating slabs.
• Loss of storage space.
• Because there is no space in the floating slab for a sewage line, a trench must be dug during the construction.
• Floating slabs are ineffective for overloaded bearing structures.
• Repairing a floating slab is costly.
• Sometimes, the resale value of the house is lower because of the missing basement.
Uses
Floating slabs are mostly used for the following buildings
- Accessory buildings
- Garages
- Drive sheds
- Houses & cottages
- Barns.
FAQ
What are the advantages of floating slabs?
A floating slab offers numerous benefits, including cost efficiency, reduced construction time, enhanced stability, accessibility, resistance to moisture problems, and versatility in flooring options
What are the advantages and disadvantages of slab?
There are good reasons for building or buying a house on a slab, such as cost savings and less risk of damage in certain instances. The disadvantages include that heating and cooling units may have to be installed on the ground floor, which takes up living space. There is also a potential for cracks
What are the problems with floating foundations?
One of the main disadvantages of using a floating concrete slab is that it may not be as durable as other types of foundations. This is particularly true if the ground beneath it shifts or settles over time, which can cause the slab to crack or become unstable
Is a floating foundation good?
Floating foundations are desirable for the following types of soils: Soils which have a good shear strength but have a problem of large settlements and differential settlements under heavy loads. In this case, a floating foundation can reduce the settlement values to a greater extent
What are the disadvantages of floating?
Exchange Rate Volatility: One of the most significant drawbacks of a free-floating system is the potential for exchange rate volatility. Currencies can experience rapid and unpredictable fluctuations, which can introduce uncertainty for businesses engaged in international trade and investment
Which type of slab is best?
Two-way slabs: Two-way slabs distribute weight in two perpendicular directions. This is ideal for larger areas with support on all four sides, such as commercial buildings, multi-storied buildings, and parking garages. Flat slabs and waffle slabs are popular two-way slab choices
What are the disadvantages of flat slabs?
Disadvantage of Flat Slab System
The major disadvantage of flat slabs and any beam less system like flat plate is their lack of resistance to lateral loads like wind loads and seismic forces. Due to this, we may have to adopt a single system where the entire lateral forces are dumped in to the shear walls
What are the disadvantages of a slab foundation?
Gas and Water Lines: One of the biggest downsides to slab foundations is that there isn’t any space to run gas and water lines, which means they have to be embedded in the foundation. When your pipes wear out, you’ll have to open your foundation to replace them, increasing the cost and lengthening the project
