What Is a Floating Slab?
A floating slab is another type of concrete slab that is placed on the ground without any kind of support. There are two stages to the slab’s construction. First, each footing is cast separately, and then the center floor of the slab is poured.
The floating slabs significantly lessen the amount of ground preparation that is required. The floating slab is also referred to as a monolithic slab because it is not connected to the foundation.
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.
How Floating Concrete Slabs Work
When compared to conventional slab foundations, floating slabs offer a more cost-effective option. Although they are designed to “float” on the ground without the need for direct supports like beams, footings, or thicker edges, floating slabs don’t require a lot of excavation.
Why Use Floating Slab?
One of the most cost-effective foundation building techniques is floating slab. Strip footings with frost walls above are necessary for conventional foundations. Typically, the strip footing is placed 4 inches below grade below the frost level. A strip footing and frost wall requires extra excavation, concrete, and labor, which raises the cost.
Types of Floating Slab Foundations
The only real type of floating slab foundation is a concrete slab that is poured straight onto the ground by a contractor into a concrete mold. There are two types of slab foundations that some people refer to as floating slabs, however this is a misnomer.
Slab-on-Grade Foundation:
Concrete footings are typically used on slab-on-grade foundations to provide additional support for the slab. To reach below any soil that can freeze or expand in the presence of precipitation, the footings are positioned a few feet below the earth.
Monolithic Slab Foundation:
Footings that extend into the earth are also a feature of a monolithic slab foundation; however, instead of pouring footings separately, the home builder will pour a single concrete slab with built-in footings.
Construction of Floating Concrete Slabs
Site Preparation
Land clearance and inspection are necessary for the first phases of construction. In order to remove dirt and fill it with concrete, this entails removing trees and the top layer.
Excavation
Frost walls usually require channel-like trenches that are 4 to 6 feet deep. Additionally, footing can be needed, depending on the building.
Laying Gravel Base
In order to let excess water drain, gravel is placed over the area in this phase.
Reinforcement for Slab
Following the gravel base’s installation, reinforcing must be prepared in accordance with the structural design. During reinforcement, lapping should take place in a variety of ways rather than in a single spot.
A good foundation needs to be robust enough to support all of the loads that the building and the environment will put on it.
Shuttering
It’s time to start shuttering now. A smooth surface, correct alignment, and high-quality work may be necessary for the formwork. After shuttering, the cover block should be secured to keep the formwork from opening while the concrete is being poured.
Pouring Concrete
Ready-mixed concrete can be used for floating slab concreting, or concrete can be prepared on-site in a concrete mixer. To obtain high strength, all ingredients are combined in an appropriate mixer machine.
During the concreting process, proper compaction should be carried out. It is either mechanically vibrated or compacted by hand, depending on the region and workmanship. The shuttering should be taken down after a day.
Curing
After the shutters are removed, the slab needs to cure for seven days. For concrete to reach the appropriate strength, curing is crucial. Water is sprayed for curing.
Floating slab foundations have a role in building, just like any other kind of foundation. Before installing this sort of foundation on your property, you should weigh its benefits and drawbacks.
Advantages of a floating slab:
- The most economical foundation design
- All soil types can use it.
- Absence of exposure to elevated water tables
- may work well for modest home additions.
- Small constructions can be DIYed.
- Minimal problems with moisture
- Very little chance of a pest infestation
Disadvantages of a floating slab:
- Frost heave is a possibility.
- Not the best option for colder climates
- Unsuitable for big constructions
- Repairing it can be costly.