A foundation for two identical buildings may be different, even if they are within the same city block. The types of building foundations vary because of the soil composition that the structures are built upon. However, there are several common building foundation types that can be found in a majority of buildings both commercial and residential.
Residential Foundation Types
Residential foundation types are most frequently constructed with concrete and wood. Here are three foundations and types you have probably seen:
Poured Concrete/ Slab Foundation
The vast majority of homes are build upon poured concrete or slab foundations instead of other residential foundation types. The diagram above shows one way a slab foundation is built. The depth of the footing and the foundation wall can be adjusted depending on whether or not the home is to have a basement. For areas with high water tables, a shallow, ground level foundation is acceptable. Severe winter freezes may require that a foundation wall be deeper, such as with a basement, placing the foundation below the frost level.
This style of construction applies a small alteration to the poured concrete style. In place of a solid concrete wall, hollow concrete bricks, held together with rebar mortar, serve as the foundation. CMU foundations offer several benefits such as reduced costs from maintenance and repair, enhanced noise isolation, and avoiding issues caused by insect damage or mold growth.
Permanent Wood Foundations
Of all the options, this is the quickest and cheapest form of foundation construction. There are some clear benefits to this style when building on a budget. Wood foundations also provide excellent insulation and can more easily be finished than a masonry foundation. It does come with its tradeoffs. Wood is far more susceptible to decay, insect infestation, and water damage.
Commercial building foundation types
The big difference between commercial and residential foundations types is the load they must support. Small commercial buildings can be built using the same slab or CMU foundations, but large buildings need more support. Additionally, things like parking garages, elevators, and other aspects of commercial buildings change how a foundation is constructed.
Although there are many commercial building foundation types, here are a few you way have come across.
A mat foundation is much like a slab foundation and is even often referred to by that name. This commercial building foundation type is a good choice for moderate sized steel or other light metal buildings. Heavy column and wall loads are built across the mat to distribute weight. Mat foundations are commonly used in areas that require basements. This is also a versatile method that can be classified as either a shallow or deep to meet different construction conditions.
Pile foundation is a broad term that can be used to describe several foundations and types. In general, a pile foundation refers to a system that transfers the load of the building to a deep layer of rock or other solid strata. This form of foundation is ideal for areas with unsuitable surface soil, that experience high winds, or that have frequent earthquakes.
Pier, Footing, and Grade Beam
Referring back to the diagram provided for residential housing may help you understand this commercial building foundation type. It it similar to pile foundations but does not require the deep drilling and rock strata. This foundation style use a series of piers to distribute weight which sit upon rectangular footings placed at a reasonable depth. This means the structure maintains some resilience against wind uplifting and poor soil conditions. The added benefits and versatility does increase cost, but this system is recognized for its reliability.
Foundation and Types of Repairs
Even a well built foundation may run into issues. Natural and unnatural forces are always working against the structure. With time, some repairs may be necessary to keep a foundation safe and strong.
So, what are the types of foundation problems you can encounter and how do you repair them? Although not comprehensive, here are three things to consider.
Tree roots can cause a surprising amount of damage. Given enough time, roots can break through concrete. You have probably seen many cracked sidewalks showing signs of a tree’s persistence to grow. Tree roots can also break through pipes, causing dangerous leaks underneath a foundation or causing plumbing backups that result in internal damages.
To prevent this problem, look into a root barrier installation. A root barrier is a small, underground wall. With the root barrier in place, roots are prevented from growing toward pipes or foundation walls.
Broken pipes can lead to a number of problems. An irrigation leak, even from a very small hole, can waste more than 8.000 gallons of water a month. Ground beneath the foundation can become saturated. The softened soil will cause a foundation to sink. Adversely, soil rich with clay can expand, lifting part of the structure. In both cases, a shearing force on the foundation will result in cracks throughout a building.
Water supply line and sanitary leak detection through hydro-static or isolation testing can identify leaking pipes. Additionally, tunneling or break-through plumbing repairs can correct the problems and prevent future damage.
Many things can lead to poor soil conditions. Long periods of rain or drought will alter ground moisture levels. Harsh winters or uncommonly strong winds will take a tole. Foundations are built for specific soil types and weather patterns. Anything breaking from the norm may put a foundation at risk.
Depending on where the problem is located, different procedures can be used to repair damage. A polyurethane repair will lift and stabilize the interior slab-on-grade. If the problem is found to be a load bearing exterior and interior grade beam, then pressed pier repair will be the best option.
Concrete lifting will fix unevenness, warping, and other issues. It is a common alternative to concrete replacement as it only cost a fraction of the price. This repair can be used in many different foundations and types including sidewalks, pathways, slabs, roads and foundations.