Foundations and Commercial Buildings

Not all Commercial Buildings use the same Foundation

A concrete slab being poured over rebar for a commercial foundationCommercial foundations are similar to home foundations. However, there are differences, especially when it comes to load-bearing capacity and foundation design. Most commercial buildings, such as an office building, will clearly have more traffic than a regular home, so it needs to be extremely stable from the start.

There are numerous structural elements that are involved in a commercial foundation. These types of buildings range from one level to several floors, so you’d have to take into account dead loads such as walls, floors, and ceilings; live loads which change in position and magnitude, such as people or vehicles (such as in a parking garage); and then there are environmental loads such as heavy winds, potential tornadoes, excessive rain, and temperature changes.

Various Foundations Used in Commercial Buildings

Much of the planning for commercial construction and foundations depends on the overall environment, especially the type of soil in which the foundation will be laid. Some commercial foundations use slabs and piles, but there are other types that are also frequently used.

Pile Foundations

In most commercial foundations, you’ll find deep and shallow ones to be the most common. Pile foundations are considered deep ones, as they go very deep into the ground, sometimes through unstable soil, until it reaches dense layers of rock at the bottom.

Piles are lengthy columns, usually made out of concrete or steel, and they’re ideal in helping transfer the overall load of the building, especially if the soil has a high water content, usually related to groundwater or drainage issues. They also come in handy if the building encounters heavy live loads.

The T-Shape Foundation

The T-shaped foundation is one type of foundation often used in climates where it’s often cold and the ground freezes. If the ground is frozen, there is often a greater amount of load on the foundation, but a T-shaped foundation can help prevent damage from occurring if the ground is frozen, especially if you have a tall building.

Concrete footings are placed below the frost line in an upside-down T shape, with walls constructed on top of the footings, that spread out past the surface of the soil. Once the walls are established, a concrete slab is then poured between them. This type of foundation can be extremely expensive as it requires at least three concrete pours to complete.

Spot Footing Foundations

The footing is considered the base of any foundation. Spot footing, also known as continuous footing, is a shallow foundation that is common in commercial construction. The footing helps columns and/or grade beams distribute the load around the foundation of the building. Spot footing supports points of contact, like beams or posts, and concrete or rebar is used to help reinforce the overall foundation to help it with extra weight.

Spread Footing or Individual Footing

A spread footing can be used to help support columns and walls while distributing any load hitting the structure to the soil underneath without surpassing the soil’s bearing capacity. This process is designed with concrete and rebar and is more durable than other footing foundations, as it helps to spread the foundation’s weight over a greater surface area. There are four types of spread footing: isolated spread footing, combined footing, strip footing and mat foundations.

Mat or Raft Foundations

Mat foundations or raft foundations consist of a thick concrete slab that rests on the ground and is reinforced with steel, columns or walls and transfer loads going from the structure to the soil. This type of foundation often covers the entire area of whatever structure it supports.

Mat foundations are used to control differential settlement and are a great option if the soil has low bearing capacities. They require less excavation and the foundation and ground floor of the building can be poured at the same time. It works in poor quality soil and is quite resistant to excess water or flooding.

Slab Foundations featuring Grade Beams

The slab foundation is commonly used in many home foundations, but it’s also used for commercial buildings, as it’s a cost-effective choice. For this type of foundation, grade beams, castings, and reinforcements are intermingled with the concrete slab, to help support the structure’s walls where there is a balanced, or uniform load of weight. You’re more likely to find this type of foundation in Central Texas, where the ground doesn’t freeze as often, compared to the Northeastern United States.

Repairing a Commercial Foundation

Regardless of the different types of commercial foundations that exist, there are bound to be issues with settling, shifting, cracks in the walls, leaning walls, water leaks, cracks in the concrete, and even uneven floors over time. Other issues can be responsible, such as poorly mixed concrete, soil moisture, and soft ground (for example, soft ground is considered the main cause behind the Leaning Tower of Pisa’s four-degree lean). Depending on what type of commercial foundation you’re dealing with, there are options to help reinforce or repair any possible damage.

This may include:

  • Underpinning techniques, if your foundation is sinking
  • Steel push piers can help transfer your structure’s weight
  • Piling, which allows for piles to be inserted in the ground and then are removed and filled with concrete to help support the structure
  • Soil nailing, a shoring technique that helps stabilize shifting walls and retaining walls

About Done Right Foundation Repair

Locally Owned, Texas Proud

Done Right Foundation Repair was created over 20 years ago by Chris Felsing with the support of his family. He started with a small team and a big dream, learning the ins and outs of foundation repair as he went. He and his team looked for ways to provide a complete solution to all foundation issues and have worked tirelessly for the past 20 years to master their craft. Our Central Texas locations: Done Right Foundation Repair in AustinDone Right Foundation Repair in New BraunfelsDone Right Foundation Repair in San Marcos