Footings & Foundation

Under most houses is a solid foundation upon which it rests, and under most of these foundations are footings. In a majority of cases, the foundations and footings ware made of concrete. The foundation is what the entire house should reside on; it transmits some of the loads of the structure to the supporting soil. Footings are an important part of the overall foundation construction. They are there to support the foundation, prevent settling, and add strength. In some regions, construction was observed to have several factors that could potentially cause damage or failure to the foundations or building envelope. Some examples and locations are shown below.

In this example there is exposed electrical wiring which could lead to electrical fires with earthquake activity. This house is also built on stilts. In this case, the structure was observed to be unattached to the stilts, which makes this structure vulnerable to the uplifting force of water. Adding bracing or support brackets from the stilts to the underside of the floor structure could significantly decrease the likelihood of significant movement and subsequent damage.

Exposed electrical and insecure stilts in Bali:

Footing go below ground and will vary in depth and width based on the soils and building structure. Below is a sample of a trench dug out for the upcoming placement of footings. This type of trenching and placement of footings below ground is highly recommended to improve building strength and stiffness.

Dugout for footings in Lombok:

The foundation, in cases of liquefaction where the ground becomes almost fluid-like, can essentially float like a boat if it has enough strength and stiffness. However, this can only occur if it is solid, reinforced both horizontally and vertically, and amply connected to what rests above it. Below is a sample of a strongly reinforced foundation that would likely perform well in an earthquake/tsunami situation.

Strongly reinforced foundation:

Below is an example of a house from Lombok that does not demonstrate these features. Notice that there is minimal support as well as a lack of footing stability. Minor shaking would likely cause this support structure to fail.

Faulty foundation in Lombok:

Learn more

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License