Your foundation may be the most important aspect of your home. It’s the base of the entire structure. Even the word “foundation” has made its way into popular culture; its how we describe one’s character, morals, and the basis of their ideas. If your foundation is weak, everything else built upon it suffers. Without a solid foundation, what would your home look like?
Well, it turns out you don’t have to look too far to see what a house without a solid foundation looks like: there are still examples of them today. If you head over to areas of South America, you may see many stilt houses. A stilt house is built upon raised piles, typically over a body of water. They help to prevent flooding in low lying areas. More and more houses in the Gulf Coast are being built or converted to stilt houses. And while modern stilt houses use sturdy steel materials, the old fashioned wood stilt house may not provide the most solid foundation over the years. If you didn’t live on stilts, you could always live in a pithouse, which typically consists of a hole dug in the ground surrounded by wood and mud. Or you could live in a house with a saddle stone foundation, where the entire structure rests upon a few big rocks! We’ll touch on all of these as we continue down the path of foundation history.
Home Foundations of the Past
We probably take our foundations for granted. Of course our house would come with a solid, concrete foundation; why wouldn’t it? But foundations were not always as solid as they use to be. Foundations and the methods of repairing them have come a long way.
Step into our handy dandy Kent Foundation Repair Time Machine and come with us as we explore the history of foundations and foundation repair methods. Our first stop is roughly 15,000 years ago in the Upper Paleolithic age, where the earliest remains of “pit dwellings” were discovered. Typically, pit dwellings relied on a dug out area in the ground surrounded by a structure of wood, animal hide, or even bone. It is still debated whether these pit dwellings were used as homes or storage pits. Postholes were later added to pit dwellings to provide additional support for a roof. This is our first early example of post in ground construction. Early postholes were dug to support wood or stone protruding from the ground. This is the earliest type of “foundation” used, which relied on digging out of the ground or simple placing a post within the ground to stabilize the structure.
Additionally, the earliest known use of primitive concrete appeared in 6500 BCE by Nabataea traders in ancient Syria and Jordan. They were able to construct simple concrete foundations and floors, as well as rubble houses. Some of these structures still exist today.
Possibly the most famous example of concrete use was by the Romans. In fact, the Romans may have been one of the first civilizations to utilize concrete foundation repair. They would add horsehair to concrete to reduce the liability of cracks when the concrete hardened. The Romans also discovered that adding blood would make concrete more frost-resistant. Can you imagine if your contractor recommended horsehair and blood for your foundation!
For the next 700 years, the Romans used concrete extensively. It allowed them to make more complex structures such as domes, arches, and vaults. After the fall of the Roman Empire, knowledge of concrete was somewhat lost until the 14th century, where it gradually started to return. It wasn’t until hundreds of years later, in 1849, when reinforced concrete was invented, along with massive structures like the Hoover Dam.
As time progressed to around the Early Bronze Age in the 21st century BCE, the earliest large-scale buildings started to appear. These buildings used more advanced techniques with stone and brick. The larger buildings and temples would have stone foundations.
From this point onwards, foundations split into multiple techniques all over the world. In England and Northern Spain, padstones (or Staddle stones) were commonplace. In Germany, German fachwerkhaus, which have a foundation of stone or brick usually several meters high, was a popular housing design. Additionally, Poteaux-sur-sol (Post on a sill) construction was a type of post in ground construction used by the early French settlers of North America between 1534 – 1763.
Rubble trench foundations, an ancient style of construction, was brought back to life and popularized by Frank Lloyd Wright in the late 1800’s and early 1900’s. Rubble trench foundations utilize rubble and loose stone to improve drainage and reduce the use of concrete. To properly create a rubble trench foundation, a hole must be dug below the frost line. The frost line is used to describe the depth at which groundwater in the soil freezes. The frost line varies slightly from different demographics. It ranges from zero to six feet in the United States alone. Most building codes require foundations to meet the frost depth requirement because frost heaving can cause significant damage to a building’s foundation.
Evolution of the Modern Foundation
The word foundation comes from the Latin word fundatio or fundare, which means to lay a base for, confirm, or establish. Fundare can also mean bottom or base. Fonder and Fondation arose as Old French words and merged with the English word found to create foundation in late Middle English. Found is defined as establish or originating. It could also mean to construct a base for. The word foundation, has declined in use since the 1760’s. Here’s a graph showing the popularity of the word foundation in print media since the 1500’s.
Of course, with the advancement of foundation technology, foundation repair techniques also changed. Unfortunately, before the technology had caught up with foundations, there was typically not much that could be done for older foundations in need of repair. Minor repairs, like cracked plaster in stone foundations, could possibly be repaired, but major repairs like crumbly mortar or gaps in the joints may have required a professional mason to resolve.
It wasn’t until the mid 20th century when technology advanced enough to dig deep foundation holes. This allowed for the rise of taller buildings and eventually skyscrapers. Deep foundations allow for larger design loads using excavation and drilling. Timber can be used for deep foundations, as well as concrete and steel.
Deep foundations are typically installed using a pile driver. Pile drivers have a unique history of their own. The earliest known pile drivers were used around 55 BC by the Romans and the earliest known drawing of a pile driver appeared in 1475. Modern pile drivers use hydraulic motors, counter-rotating weights and vibrations to install foundations more than 100 feet into the ground.
The other type of modern foundation is the shallow foundation. Shallow foundations transfer soil loads to the surface rather than a range of depths like a deep foundation. Typically shallow foundations include earthbag foundations, slab-on-grade foundations, and rubble trench foundations.
Foundation Repair Tools and Methods
Today, foundations can be repaired with advanced machinery. Techniques that were typically impossible can now be resolved, and foundations can be repaired and even strengthened, adding durability to the building. Some of the tools used for modern day foundation repair include screw-piles (or helical piles), earth anchors, and retaining walls.
Helical piles themselves are not a new technology. Screw foundations appeared as early as the 1800s, primarily used as pile foundations for lighthouses as well as piers for harbors. The wrought-iron screw-pile was created by Alexander Mitchell in 1833, and allowed for improved construction over the standard straight-pile method. However, helical piles had existed for over a decade by the time Mitchell introduced his new screw-pile design. Screw-pile lighthouses and piers stand on piles that screwed into sandy river and ocean bottoms. Over 100 screw-pile lighthouses were placed along the United States east coast between the 1850s and 1890s. The original helical piers had limited load-bearing capacity. Modern day helical piers can hold a weight exceeding 200 metric tons. Modern helical piers also offer a variety of designs for different concrete and steel structures. They are still used today for roads, rails, lighthouses, and telecommunications. They are heavily favored for their ability to be used on pre existing structures as well as their fast installation. Helical piers offer a number of benefits, including easier installation, shorten project times, reduced costs and risk, and a smaller carbon footprint.
As for concrete repair, we have developed far more advanced methods that allow for concrete restoration with minimal effort. One of the most popular concrete repair methods is concrete lifting, or slabjacking. Slabjacking (also known as mudjacking) is a procedure that lifts sunken concrete by pushing it from below using a pump system.
Retaining walls are another design in the foundation family that have existed for some time in history. Retaining walls are designed specifically to prevent sloped soil from naturally falling off. They are especially useful on hills and steep slopes, and allow for two different elevations in areas that would typically be surrounded by hills. The most recognizable type of retaining wall that you may be familiar with is a basement wall. A basement wall allows for a flat elevation (ie, your basement) where the surrounding soil is uneven or sloped. Basement walls are built to resist pressures and pushes from the surrounding soil, but sometimes they need extra support.
Another modern form of foundation support is earth anchors. They are also known as ground anchors or mechanical anchors. Earth anchors can be used to support retaining walls. Similarly, helical tiebacks can also be used to provide additional support for retaining walls. Unlike an earth anchor, helical tiebacks are horizontal wires or rods that are used to reinforce and stabilize retaining walls. One end of the helical tieback is anchored into the surrounding soil, while the other end is attached and secured to the wall. Helical tiebacks also work hand-in-hand with helical anchors.
Making History With Each Repaired Foundation
As you can see, foundations and foundation repair methods have a long and interesting history. Some knowledge was lost, some was improved upon, and who knows what we will discover about foundation technology in the future. Kent Foundation Repair has even worked on repairing historic homes. We completed a foundation repair job on a 150 year old house that required commission approval. In repairing the support for the historic home, we wanted to be as unintrusive as possible. This particular home had a Michigan basement, meaning that it has shallow footing. However, that shallow footing consisted of a single rock layer with weak mortar. After consulting with a professional architect, we were able to install helical piers without extra pressure or vibrations to ensure the structural integrity of the house. We are proud to say that site disruption was kept to a minimum. You could say that we have become a little bit of history ourselves.