Block

• Reinforced concrete foundations are often constructed from individual concrete blocks, which are similar in shape to bricks. Cement block walls are generally weaker than poured-concrete walls because they are hollow. This means that block walls are probably a bad choice for larger houses or structures.
  
  

Poured Concrete

• If the concrete foundation is not built of individual blocks, it is made of concrete, poured in one or more sessions on or off-site. The three types of poured concrete foundations are slab-on-grade, T-shaped and frost-protected.
  
  

Slab-on-grade

• A slab-on-grade foundation gets its structural reinforcement from its graded edges. The concrete is poured thicker on the edges and thinner in the center, weighing and balancing the foundation so it stays in place. Because this type of foundation does not penetrate the frost line in the ground, it is not ideal for colder regions.
  
  

Frost-Protected

• A frost-protected foundation is structurally similar to a slab-on-grade. The main difference is that frost-protected foundations have layers of insulation that protect them from frost damage by trapping heat. These layers only function, however, if the house or structure is heated.
  
  

T-shaped

• T-shaped structures are the alternative to the slab-on-grade style. They are made of one even slab of concrete, supported by feet that go farther beneath the ground. These feet penetrate the frost layer, preventing structural shifting during frosts.