Recognizing that the rehabilitation of existing structures represents approximately half of all U.S. building construction activity, comprehensive codes that deal specifically with this type of project are evolving.
New Jersey and Maryland now have codes that specifically address alterations to existing buildings, and the International Code Council (ICC) plans to issue a similar document in 2003. ICC released the final draft in August.
While current building codes typically have chapters that deal with alterations to existing structures, they are focused primarily on new construction. Some jurisdictions, including California, have stand-alone codes that apply to historic buildings. However, codes that are focused primarily on new construction lack predictability with regard to what is required when renovation involves existing buildings. This gives building officials considerable latitude in enforcing them, making it difficult for owners and design professionals to determine the scope and cost of work that will be required, according to Hamid Naderi, senior staff engineer with ICC.
The advent of codes for existing structures is designed to answer questions such as whether alterations would require enclosure of existing open stairways, Naderi says.
New Jersey was the first state to issue a comprehensive code for existing buildings. Its Rehabilitation Code establishes requirements according to five categories:
"Repair" is defined as fixing a worn or damaged building component with another that is the same or nearly the same.
"Renovation" encompasses removal and replacement of interior or exterior finishes, doors, windows, trim or other materials with new materials that serve the same purpose.
"Alteration" involves reconfiguring interior space by adding or removing walls, doors, stairs or windows, or by changing ceiling height.
"Reconstruction" is a combination of repair, renovation and/or addition that is so extensive that the building—or a significant portion of it—cannot be occupied during the project.
"Change of use" covers a change in the building's purpose or its primary activity.
Citing the New Jersey Rehabilitation Code's impact in upgrading structures in major metropolitan areas since it was released in 1999, William Connolly, director of the state's Division of Codes and Standards, says projects involving existing structures increased by 62 percent in the state's 16 largest cities, compared with a statewide increase of 15 percent.
The International Existing Building Code under development by ICC establishes three levels for alteration projects: Level 1 includes the removal and replacement, or covering, of existing materials, elements, equipment or fixtures. Level 2 includes the reconfiguration of space, the addition or elimination of any door or window, the reconfiguration or extension of any system or the installation of additional equipment. Level 3 alterations apply where the work area exceeds 50 percent of the aggregate area of the building. The provisions that deal with requirements for renovation of flood-damaged structures are the only ones triggered by a building's market value, according to Naderi.
Maryland adopted a code for existing buildings that became effective this summer. Like the other similar codes, Maryland's attempts to eliminate the "gray areas" of code application to existing structures, according to Lawrence Perry, a codes consultant whose clients include Building Owners and Managers Association International.
The state of Minnesota has issued a guide for renovation of existing structures that is based on the Nationally Applicable Recommended Rehabilitation Provisions developed by the U.S. Department of Housing and Urban Development.