The company designs and constructs seismic/wind load-rated rooftop curbs. Rated curbs resist the effects of site-specific forces determined according to the requirements of the International Building Code or other applicable codes. Curb walls are constructed of heavy-gauge galvanized steel, and appropriate wall thickness is determined by project-specific analysis of curb wall stresses generated by the seismic/wind load acting on the rooftop unit. Curbs can be provided in insulated, uninsulated, and vibration-isolated styles of various heights for sloped or flat roofs. Wood nailers are provided for attachment of roofing material. Project-specific seismic/wind calculations can be provided for the roof curb, the connection of rooftop equipment to the roof curb, and roof-curb connections to the building structure. Calculations will be signed and sealed by a professional engineer registered in the state where the project is located.