Observations and Analysis

The folloing are some common types of foundations.

1. Concrete footing

The most common residential foundation consists of concrete stem walls supported by concrete footings. When the wall height goes beyond certain limit, engineering becomes required.

2. Piles and grade beams

When the subgrade soil is not suitable for supporting the footing, or shallow soil strata is too weak, piles and grade beams configuration may become more economical. Usually this type of foundation needs to be engineered.

3. Raft slab foundation

Raft slab foundation is not very common in residential applications. There are certain situations that this is more suitable than other types of foundations.

4. Rock/Soil Anchors

When foundations sitting on bedrock, the rock anchors may be the best choice. Sometimes rock/soil anchors are required for constructablity reasons.

Conclusion

There are different foundation choices for different geotechnial conditions. Choosing a wrong foundation type may cause uneven settlements, cracks and/or higher construction cost. Both geotechnical and structural engineers may be involved for some situations.