The six-story home in Nairobi, Kenya's capital, collapsed after heavy rain, killing more than 80 people. While inquiries into the cause of this fall continue, we look at several prevalent issues. 1. The foundations are insufficient. Adequate foundations may be expensive. They can be as simple as footings poured over old or abandoned wells to prevent erosion and sliding. In some cases, they can include retaining walls, terraces, and other structures. However, even with adequate foundations, buildings will eventually fail due to soil instability under them. Heavy rains can cause dirt under foundations to move, which can lead to collapses. In this case, the house had been built on land that had been excavated for a well but never filled in. This left a gap between the house and the foundation, which allowed water to seep inside and weaken the structure. A similar incident occurred in Mumbai, India in 2012 when another building collapsed due to poor construction. Two years earlier, a nine-story residential building in the same area failed because its foundations were also damaged by the well excavation. These incidents show that even if you build your house properly, keep an eye on how much water is being taken up by the yard and make sure that there are no cracks in the ground under it, you still need to maintain it regularly so that it doesn't collapse.