All about the Base: Everything You Must Know before Your Home Sits on It
The importance of the foundation of your home cannot be stressed enough. Any mistake in its construction is bound to create serious consequences, known as compounding defects. Since your home sits on top of it, its quality guarantees the future of the durability and integrity of the structure.
These are just some of the functions served by a house’s base:
- The load bearer
Foundations must support the dead and live loads of the structure built on top of it. To explain, dead load refers to the constant weight of the structure, while live load is defined as the changing weight of the structure’s contents such as people, furniture, appliances, etc. Rigidity is crucial in ensuring the foundation can transmit the weight it bears into the ground without giving in.
- A guard against the rise of ground moisture
For areas where wooden buildings are common and levels of ground moisture is high, rotting posts and flooding basements are constant issues. To protect your house from these problematic conditions, especially if you live in damp areas, sealed box foundations with concrete slabs can keep the unwanted water out.
- A bulwark against the vicissitudes of natural forces
If you are familiar with the story of the three little pigs, consider the forces of nature as the wolf that would huff and puff and blow your house down. No one wants to end up like the first and second pig, so it’s important to ensure that your foundation is strong enough for your house to survive earthquakes, strong winds, tornadoes, floods, tsunamis, and frost-heaves. Hence, a building which is securely bolted to its foundation will keep the structure in place, making it less likely to be swept away by natural disasters.
Site analysis: essential considerations for foundation design and material
Completing a foundation design is a highly specialised task best left to professionals. It is usually done by a structural engineer, and it demands a comprehensive study and examination of several relevant elements. For instance, how much depth is required for your foundation depends on:
- The type of soil beneath the structure
- How much load can the existing soil bear
- The depth of frost penetration if the ground consists of silt and fine sand
- The height of ground water
Once these components have been identified and examined, the engineer can now recommend and select the location, depth, and width of the foundation, and ensure that the material used can guarantee maximum bearing capacity and shear resistance.
Choice of material
With the development of modern technology, the types of house base material used have changed throughout history. Historic types include posts in ground, earthfast construction, timber pilings, padstones, dry laid stone foundations, and rubble trenches. Today, foundations are typically made of:
This flexible construction material can be used on almost every building project imaginable – including foundations. Concrete is a popular choice for box foundations that double as basements. They’re fairly easy to construct, wherein you must first build a wooden frame, pour concrete into it until it hardens, remove the frame, and they’re good to go.
- Concrete block
Also called breeze blocks, they look like large bricks but are made of concrete. They weigh lighter than what you might expect, but they have the capacity to be heavy duty and frost resistant.
Metal is often added to concrete foundations for additional reinforcement, strength, and rigidity.
- Bricks and stones
They are still used today, although they are more vulnerable to water damage as stones tend to have gaps in between them.
Working with wood is actually an effective means of creating a strong, durable base for your home. Opt for pressure treated wood to prevent rot and termites from consuming it.
Once the site analysis has been completed and the material has been selected, another part of the construction process consists of selecting the type of foundation that will work out best according to your structural needs.
Also known as footings, they reach a depth of just about a metre or so. They include spread footing and slab-on-grade. In spread footing, concrete strips or pads are used to embed the soil just below the frost line to transfer the weight of the structure into the ground. Meanwhile in slab-on-grade foundations, the weight of the structure is transmitted through a concrete slab.
This type is used to transmit the load all the way down to the subsoil, which is stronger than the topsoil. Deep footings include drilled shafts, earth-stabilised columns, helical piles, impact-driven piles, caissons, monopiles, and the like.
Foundation strengthening measures for superior durability and rigidity
In construction and renovation, there are two primary techniques in strengthening the base of your home, depending on the findings of the site analysis.
Typically, piling is utilized as a means to fortify unstable bases, especially those of structures with enormous vertical loads such as multi-storeyed buildings. Piling methods are divided into two categories:
- Driven piling
Hammering a precast pile into the ground results in soil displacement, but is proven as an effective way of making the base durable.
- Bored piling
Hydraulic pressure is often used in drilled piling and the piles are casted on site.
Underpinning, on the other hand, is utilized when:
- the usage of the building has been altered
- the properties of the soil has changed
- existing foundations need an increase in load capacity
- natural forces destroyed the structure
- nearby construction results in the excavation of the soil beneath existing foundations
Underpinning methods include resin injection, mass concrete, beam and base, and mini-piled underpinning. In the UK, Belowground specialises in providing piling and underpinning services.
Identifying foundation problems
If you suspect your house is in danger due to weak or damaged foundation, never hesitate to contact specialists in your area. You can tell your building’s base is failing if you notice the following:
- Cracks on exterior wall finishing
- Misaligned doors and windows
- Blocks and bricks separated by the joint
- Sagging or sloping floor
- Basement wall cracks
- Flooring cracks
Overall, don’t wait for your house to collapse, sink into the ground or be blown away by natural disasters. Start building it right by seeking the help of professionals, and make the necessary repairs and strengthening.