When major alterations or repairs to a building are performed due to planned renovations or fire damage, the existing structure may be impacted by current building codes.
In South Carolina, the Rules and Regulations specified by the State Fire Marshall indicate that buildings damaged or altered in excess of fifty percent of the appraised market value prior to the damage must conform to the requirements for new construction if the building is to be repaired. In short, if the building is repaired, the entire structure must comply with the latest building codes, and not just the portions of the building being repaired or replaced.
Current codes require new construction to withstand external loads imposed by wind and earthquakes. The intensity of the loading, and the use and location of the building determine the minimum construction requirements.
For masonry and concrete structures, minimum construction requirements include building geometry, such as height and length, wall support, and minimum steel reinforcement. Existing building construction may not meet these requirements, and remedies may greatly increase the cost of the project. Also, modifications required for code compliance may be technically infeasible, meaning that the modifications cannot be performed due to the impact on critical elements of the structure or the inability to access areas of the structure requiring modification.
For instance, a fifty year old masonry wall may require the addition of steel reinforcement due to seismic classification. Inserting steel into an existing wall would require access to the top of the wall, which could require the removal of primary roof structural elements. Also, the steel reinforcement would have to continue into the existing foundation to positively connect the wall to the foundation, and could be difficult to achieve without removing large portions of the existing wall and foundation.
Some insurance policies have provisions pertaining to compensation for required code structural upgrades. Knowing the age, general construction characteristics and wind and seismic loading potential can aid in determining the modification potential to the structure. A Professional Engineer can inspect the structure and apply current code provisions to provide insurers with information useful for evaluating claims.