Building a house requires a solid foundation to support the structure. Various types of foundations can be used. These foundations provide stability and support to the structure, while also distributing load to the ground efficiently. Foundations can be designed according to most recent national building codes.
Typically, residential construction projects use concrete masonry and cast-in-place concrete. However, other materials are available. The material and type of foundation that is best suited for a particular building depends on a number of factors.
Generally, the depth of the foundation should be in accordance with the structural design of the structure. Normally, the minimum depth of the foundation should not be less than 50 cm. The depth should be enough to accommodate variations in ground level. This is to prevent uneven ground settlement. In addition, the depth should be sufficient to allow removal of topsoil. Depending on the soil type and bearing capacity, the depth of the foundation may need to be more or less than 50 cm.
When designing a foundation, the first step is to determine the load transmission. This includes transmitting the combined dead and live loads. It is recommended that the foundation design also considers the wind load. If the structure is located in a region with a climate that has strong winds, the design should be made to take account of wind.
The most common type of foundations is the individual footing. Unlike concrete masonry, this foundation is constructed in brickwork or stone masonry. A footing is usually square in shape and is connected to the wall with a horizontal plinth beam.
The foundation wall typically has a thickness of six to ten inches. As with all structures, the depth should be chosen according to the structural design. For example, if the basement floor slab is located at the centerline of the foundation, the wall should be at least three times the height of the basement wall.
The wall is then strengthened and reinforced if necessary. In some cases, the strength of the wall can be increased by installing vertical or horizontal shear reinforcement. Another method to improve the shear capacity is by constructing the wall thicker.
Some residential structures are framed with a wood-frame foundation. The foundation wall is sheathed with preservative-treated plywood and pressure-treated lumber. Alternatively, a foundation wall can be made from cast-in-place concrete.
Most foundations are set at a depth where the removed soil has equal weight to the structure’s weight. This is to facilitate the transfer of the weight to the surrounding soil. Sometimes, the soil is tamped to avoid excessive settlement.
If the structure is located in a coastal flood zone, the foundation is constructed in the form of a pile. Typical applications of a pile foundation include fences, carports, garden houses, and wooden decks. Usually, these foundations are designed to withstand concentrated loads.
To ensure the proper support of the structure, it is essential that the foundation construction is carried out as per the instructions of the structural designer. The foundation layout drawing is usually prepared by the structural designer and approved by the architect.
