History of Foundations
The history of foundations can be dated back to ancient civilizations. These civilizations recognized the need for a strong foundation which enabled them to build elaborate structures that can still be seen today. A foundation must provide a strong and stabilizing base for your home. The surrounding geography and climate affect the type of foundation you can build. There are advantages and disadvantages of each type of residential foundation. Therefore, the type of foundation used must be appropriate for its environment and the area in which it is built.
Building shelters dates back to the beginning of time. Ancient civilizations already understood the importance of a strong foundation for building their homes, temples, and other structures. Many examples of the early building successes can be seen today in part or in whole. Ancient Egypt is a prime example of well-built structures with foundations. The Egyptians used thick stones made of mud to build which was not only strong but a good insulator. It helped to regulate temperature. Furthermore, the Egyptians built the pyramids using limestone blocks as their foundation. A foundation was recognized as an integral part of their building process.
Ancient Romans used concrete with their stone and brick. The use of concrete allowed for stronger more elaborate structures. These larger elaborate structures needed a strong stabilizing base to support the structure. The Romans used cobble for their materials when building a foundation for their larger structures. This allowed for the distribution of the weight of the structure. In the 20th century, Frank Lloyd Wright used some of these same principles with stones in his foundation designs. However, building science and energy efficiency has continued to influence and change building practices leading us to stronger foundations and more energy efficient homes.
Types of Foundations
In our previous blog, we discussed the different types of home foundations. The most common types of residential foundations are basements, open piers, crawl spaces, and concrete slabs. The history of foundations was affected by building costs, environmental factors, addition of garages, housing construction styles, the need for more energy efficient homes, and the geographic location in which each style is found.
However, with changes in our building practices and desire for more energy efficient buildings over the last century, other issues arose. The evolution of foundations may have solved one problem; however, new issues were created – specifically moisture and air quality issues. Like many things in life, fixing one issue often has a new unintended consequence.
History of Residential Foundations
After WW II, the number of house builds exploded across the US. The economy was good, and the American people were moving to the suburbs to live in the idealistic “white picket fence” home. There was a desire for finished basements for additional living space and garages to park cars, thus changing the style and shape of homes. The housing boom and more luxurious living styles affected housing construction.
Concrete Slab Foundation
During the housing boom, concrete slab foundations were often selected when building neighborhoods. Builders could build homes quickly, and it was more cost effective than other foundations. Furthermore, there was very little maintenance for the homeowner with this style of foundation. Basements were still desired after the war but with one caveat. Americans wanted a finished basement to increase living space. Prior to finishing root cellars and basements, the basement was built with drains to compensate for water issues. Once these spaces were built for living, water seepage and moisture issues had to be addressed differently to prevent damage to the living space.
Open Pier Foundation
Another common type of foundation is the open pier. Houses built on open piers are raised off the ground to allow for air to circulate and protect the home from flooding. These homes are often found in coastal regions and near lakes and rivers. Often found in Louisiana, the raised home design was thought to have originated from the Portuguese. The Portuguese settled in West Africa in the 1400s along with other Europeans. These various ethnic groups most likely influenced each other’s building styles. The homes here were raised to prevent flooding and allow air circulation underneath the house.
As sugarcane farming drew the Portuguese to South America, Haiti and other surrounding areas, the raised style of home was carried to these hot tropical environments. It was thought that this housing style was later brought to the US, specifically Louisiana, by the Portuguese and influenced the raising of homes to prevent flooding and allow for air circulation under the home.
The open pier foundation is still found in Louisiana and other flood prone areas in the US. However, the energy crisis of the 1970s focused on sealing homes to increase energy efficiency. With energy efficiency in mind, open piers shifted to foundations built with walls for what is known as a crawl space, or a skirt was added to close it off. Additionally, some homes were closed or partially closed for a more appealing aesthetic for the front of the home. However, closing off these spaces created new moisture related issues.
Crawl Space Foundation
The history of the crawl space foundation heavily revolves around solving moisture issues created by more energy efficient homes. Crawl space foundations have gone through a significant evolution to address the moisture issues. Much like an open pier foundation, crawl space foundations were built to prevent minor flooding issues. Over time, there have been changes in building recommendations and code to help reduce and prevent these moisture related issues.
The Influence of the Energy Crisis
In the 1940s, the FHA placed requirements on ventilating crawl spaces. This allowed for air to flow and moisture to move out of the space. By the 1950s, vapor barriers were beginning to be used in building practices to keep ground moisture from entering the crawl space. However, as building practices changed to be more energy efficient, the crawl space moisture issues increased.
Changes in subflooring and the addition of air conditioning were also contributing factors to moisture issues. After WW II, homes were using plywood as subfloors. This was a more energy efficient subflooring than the previous solid boards. However, the older solid boards were laid side-by-side allowing for air and moisture to escape through the gaps, but this was not an energy efficient building practice. As subflooring, insulation, and other sealing of the home became more prevalent, the moisture in the crawl space no longer had an outlet. It was trapped in the crawl space.
With nowhere for moisture to go, the moisture was unable to escape, and moisture related issues began to increase in the crawl space. Passive ventilation and vapor barrier requirements were set early on to slow the release of ground moisture and allowing for it to exhaust through ventilation. In the early 2000s, the vapor barrier practices increased to 100% coverage in an attempt to further control moisture infiltration. The furthering of energy efficient building may have decreased energy costs, but there was a significant problem arising – moisture and air quality related issues.
Builders continue to construct more energy efficient homes. Homes are more sealed and insulated than ever before. Some of the reasons for the ability to build more energy efficiently is more precise manufacturing processes that lead to fewer gaps and cracks within the home. These manufacturing standards combined with an increase in sealing and insulation have led to very energy efficient buildings. However, changes in these building practices have led to the need for better moisture control and air quality solutions in the crawl space.
Home Building Practices Today
The recent covid pandemic highlighted the importance of ventilation with outside air for improved air quality. Many health researchers recognize the need for open fresh air to exchange stale stagnant air to provide a healthier indoor environment. The same principle can be applied to your crawl space. The air in your crawl space affects your home’s structural integrity and air quality.
The history of foundations for homes has evolved over the centuries. More elaborate structures, changes in home design, and the desire for more energy efficient homes are influencing factors. As building practices have evolved and tightened homes, we have created other issues that must be addressed and considered when building a home. The industry does not have a definitive answer to solving all of these issues. However, government agencies have identified the need and importance for fresh outside air. Building practices will continue to evolve to meet the needs of our home and health. Furthermore, environmental factors will continue to influence these practices as they have since the beginning of time and practices will evolve to meet these changing needs.