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Strip foundations are particularly suited to light structural loadings, such as those found in many low-to-medium rise domestic buildings, with minimum strip widths applying to different ground types and total load. In the late 1940s and throughout the 1950s, most new houses were built on strip foundations, although raft foundations remained popular.

In the 1920s and 1930s, this type of foundation was common, with brick footings also permitted. They spread the load over the whole area of the foundation, in effect ‘floating’ on the ground. Raft foundations are created from reinforced concrete slabs of uniform thickness, covering a wide area. This meant that the nature and quality of foundations varied somewhat (concrete foundation, brick footings, rubble/flagstone) with depths varying according to circumstances and, in general, shallower than modern foundations. It is not known how many authorities adopted these byelaws outside London – many produced their own, less onerous rules. Common (hydrated) lime was seen as inferior.

At that time, Portland cement was seen as making the best concrete, with hydraulic lime as ‘the next best thing’. For foundations, the byelaws stated that walls should have stepped footings (twice the width of the wall) and that nine inch (225mm) thick concrete should be placed under the footings unless the building sat on gravel or rock sub-soil (‘solid ground’). In 1878, the Building Act provided more detail regarding house foundations and wall types. These byelaws were focussed on the development of new streets, ensuring the structural stability of houses, preventing fires, providing adequate and efficient drainage, and ensuring air space around buildings. The Public Health Act, introduced in 1875, was the first legislation that required byelaws to be set by the authorities. In the first of a series of posts that chart the history of modern building elements in the UK, we look at how foundation engineering has changed over the past century or so. It was in ancient Rome that foundation engineering really leapt forwards, with rules created and concrete used. A few thousand years later, the Babylonians raised their monuments on mats made from reed, and the ancient Egyptians supported the pyramids on stone blocks which rested on the bedrock. Over 12,000 years ago, neolithic inhabitants of Switzerland built houses on long, wooden piles that were driven into the soft beds of shallow lakes, keeping people high up above dangerous animals and hostile neighbours. Foundations provide support for structures by transferring their load to layers of soil or rock beneath them. Constructing foundations is one of the oldest of human activities.