We have always needed shelter, from the environment, the weather and from dangerous predators, although the predators have changed over the centuries! So the practice of building literally dates back to prehistoric times. The foundation of your home is arguably one of the most important components of your property. Foundations provide support for structures by transferring their load to layers of soil, or rock beneath them. Humans have been constructing foundations for over 12000 years. It seems that our ancestors knew the importance of foundations even back then! It has been discovered neolithic humans in Switzerland built houses on long wooden poles that were driven into the shallow beds of lakes. This was to protect them from dangerous predators. Thousands of years later, the Babylonians supported their monuments on mats made from reeds. The ancient Egyptians also used foundations, they supported their pyramids on stone blocks resting on bedrock.
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It wasn’t until ancient Rome that engineering became more advanced. Rules were created for buildings and it was at this time when the first use of concrete was recorded. Modern buildings as we know it did not make an appearance until the Victorian age and the first modern period of building happened from 1930 to 1950. The second is from 1950-1970 and the third 1970-1990. We have been in the current age of building for 30 years, if we were to look back at the evolution of building elements so much has changed. Particularly over the past century from the Victorian age. Modern building techniques, materials and designs are far removed from Victorian times.
Victorian Building Methods
The Victorian age is from 1837 to 1901. During this time England underwent a change, it was a time of improved standards, an increase in wealth and prosperity and many advancements in the industrial field and scientific research. During this time the population had almost doubled, so there was a lot of building activity to provide housing for all the people. In 1875 Because of poor building methods and serious health problems the Public Health Act was introduced to attempt to improve living standards.
The Public Health Act of 1875
Victorian houses did not have toilets, drainage systems or damp-proof courses. The Public Health Act allowed the local authorities to set some building rules and brought into action the removal of sewage by drains. This was the first legislation that enabled byelaws to be set by local authorities. It led to the development of new streets, more structural stability of houses, efficient drainage systems and air space around buildings.
The Building Act of 1875
Three years later the Building Act of 1878 provided more details with constructions- they defined foundations, damp proof courses, the thickness of walls, ceiling heights, space between dwellings, underfloor ventilation, ventilation of rooms, and size of windows. For foundations, the bylaws stated that walls should have stepped footings twice the thickness of the wall and nine-inch thick concrete should be placed under the footings.
Victorian Foundations – Stepped Foundations
Victorian foundations before the bye-laws were very different compared to our modern foundations. Modern foundations are large and usually on concrete ground or beams of reinforced slabs. The Victorians built shallow foundations out of 5-6 bricks in a pyramid shape, in a shallow solid trench and spread the load across the ground. This was known as a stepped foundation and consisted of 3 bricks on the bottom with 2 more laid on top. Some foundations were only 20cm deep! Surprisingly many of these buildings have survived the test of time and are still standing. The main problem with these shallow foundations was the shrinkage and swelling of the clay soils that are predominant across London and Southeast England. Subsidence is a major problem in these areas.
Raft Foundations
In the 1920-1930 foundations had evolved into raft foundations made from reinforced concrete slabs covering a wide area. The load was spread over the whole area of the foundation. Twenty years later 1950s foundations had changed again into strip foundations. A strip foundation is one of the most commonly used types of the foundation today, as it provides continuous strip footings of support to a linear structure, like a wall.
Strip Foundations
In the late 1940s and throughout the 1950s, most new houses were built on strip foundations, although raft foundations remained popular. Strip foundations are particularly suited to light structural loadings, such as those found in many low-to-medium-rise domestic buildings. Regulations were set out in the National Building Regulations in 1965 and applied generally throughout England and Wales, with the exception of London which had its own Building Acts. Today, raft foundations are quite rare, except in former mining areas.
Modern Evolution of Foundations
In today’s modern age, engineers and architects have choices when it comes to what type of foundation to use. There are a variety of factors that have to be considered when deciding on a suitable foundation. These factors can vary from soil condition, the type of structure being built and the loads that are involved.
The material that is being used for the construction, also affects what type of foundation is needed. Reinforced concrete, for example, will exert a much higher load on the foundation compared to a steel structure.
Type of Soils
Soil is a mixture of solid particles, water and air. There are many different types of soil. It is divided into 2 descriptions: topsoil and subsoil. The subsoil is used for the base of foundations. Before deciding upon a foundation a soil investigation needs to be performed to give details of the depth of different layers of soil, the types of soil, the depth of the water table, water content and the bearing capacity of the soil at different levels.
Foundations in the neighbourhood
Deciding what foundation to use can also be done by looking at the types of foundations already present in the surrounding neighbourhood.
Types of Foundations
The various types of foundations, commonly used today are isolated foundations, combined footings, pile foundations and raft or mat foundations, to name a few. These can be selected based on the type of soil and loads from the building.
For more information, please visit our website on basement and foundation types.