Are you planning to add a subsurface structure, such as a basement, to your home? Read on and discover some of the considerations that a structural engineer will have in mind when designing such a subsurface addition. Structural Support The structural engineer will assess whether sufficient structural support exists for the addition that you wish to construct. For example, will the basement extend beyond the confines of the foundation? Sections that are not supported by the foundation are likely to settle and can put the entire home at the risk of collapsing.