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Types of Foundations There are two main types of foundations. The first type is a shallow foundation. It is like a big, flat pad made of concrete. You put it just under the building. It is good for small buildings like houses. The weight spreads out on the ground. The second type is a deep foundation. This is for tall, heavy buildings. Engineers use piles. Piles are long posts made of concrete or steel. Workers drive them deep into the ground. They go down to strong soil or rock. The building si