Slab-on-grade foundation is the simplest type of footing used in residential construction. It is a single concrete slab, reinforced with steel to prevent cracking. It supports the weight of the building and is common in warm climates.
The most common types of footing in residential construction are Isolated and Continuous spread footings. They are both part of a shallow foundation construction hence why they are used in residential construction. In addition, the other five footing types are Raft, Strap, Strip, Pile, and Combined footings.
Precast cement blocks are probably the cheapest and easiest footings to install. Each block is buried right beneath the ground's surface.
Spread Footing
This type of footing construction is used when the soil bearing capacity is relatively low, and a larger footprint is needed to distribute the load. Spread footings can be square, rectangular, or circular and are commonly used in residential and commercial buildings.
Footings should extend to a minimum depth of 12 inches below previously undisturbed soil. Footings must also extend at least 12 inches below the frost line (the depth to which the ground freezes in winter) or be frost-protected.
According to the U.S. building codes, the minimum rebar requirements for footings vary depending on the size and type of the structure being built. Generally, a minimum of two #4 bars are required for residential footing. The rebar should be placed in a grid pattern with a spacing of no more than 18 inches apart.
For every 2 feet of adjustment to the width of the house, add or subtract 2 inches of footing width and 1 inch of footing thickness (but not less than 6 inches thick).
There are also specific foundations for homes, such as basement and concrete slab foundations.In this article, we explore what a foundation type is, the primary types of foundations, foundations specific to home building and the construction occupations that use foundation types.
C25 standardised mix concrete or ST2 Concrete is widely versatile and used in numerous commercial and domestic projects. It is commonly used for footings and foundations, including mass concrete fill, trench fill and reinforced fill, as well as general groundworks.
The most common type of footing is the shallow footing, which is typically used for small structures such as sheds or decks. Deep footings are used for taller structures such as buildings or bridges, and pile footings are used to support very heavy loads.
A concrete pad footing is the simplest and cost-effective footing used for the vertical support and the transfer of building loads to the ground. These footings are “isolated” i.e. there is no connection between them. They are also reinforced.
A concrete slab is one of the most common types of house foundations, requiring the least amount of lot prep to begin building. Installation is simple compared to other house foundation types, making slab foundations popular among homeowners for their relatively low price tag.
Simple footing is used for carrying light loads and this footing has a single projection. But stepped footing is opposite from simple footing, it carries heavy loads and has multiple projections.
An isolated footing is used to support the load on a single column. It is usually either square or rectangular in plan. It represents the simplest, most economical type and most widely used footing.
For residential buildings, the most common type of foundation used is the strip foundation. This type of foundation is suitable for buildings with light loads and is constructed by excavating a strip of soil and pouring concrete into the trench. The foundation is then reinforced with steel bars to strengthen it.
J&W Lumber recommends using QUIKRETE to build your concrete footings. Take a look at this step-by-step informational video on how to build the footings for your deck.
It is important to note that IS 456 mandates that the minimum grade of concrete has to be M20 for RCC structures and buildings. Though some of the lower grades and its strength can be achieved by volume batching, it has to be designed.
Gravel provides drainage, stabilizes the soil, prevents erosion, and helps distribute weight more evenly. Without it, you risk the potential damages listed above. If you're planning a concrete project, don't skip the gravel layer—it's a foundation that ensures your concrete work stands the test of time.
The second main factor is the kind of foundation method you choose. There are several basic varieties of foundation (more on those further down), and their costs relate to how much excavation, as well as construction, they require. Concrete slab is the most common and cheapest, and costs around $7 per square foot.
The biggest difference and advantage of concrete block foundations is that they can typically hold more weight than poured concrete foundations. If you have a larger/heavier home, your house was most likely built with a concrete block foundation because it can better accommodate the weight.
Poured concrete is the strongest type of foundation for a house. Concrete is incredibly strong and durable, and it can be poured into any shape.
Footings are usually the first thing you build when starting a new construction project. Because they need to support a significant amount of weight, footings must be made of very strong concrete. It should be at least 3500 psi (pounds per square inch).
Footings shall be a minimum of 8 inches by 24 inches (203 mm by 610 mm) for houses two and one-half stories and less. The footings for a three-story building shall be 10 inches by 24 inches (254 mm by 610 mm).
Between your foundation walls and resting on top of the footings lies your foundation slab: the giant piece of concrete which makes up your basement floor or subfloor. Each of these pieces must be poured and cure one at a time: a process that can take up to a week for each step.