Which code must detached one- and two-family dwellings comply with?

Detached one- and two-family dwellings must comply with the International Residential Code (IRC) because this code is specifically designed to address the unique needs and characteristics of residential buildings. The IRC covers various aspects including structural integrity, safety considerations, plumbing, mechanical systems, and energy efficiency tailored to one- and two-family homes.

The International Building Code typically governs larger, more complex buildings and may not address the specific requirements for residential structures as thoroughly as the IRC. The National Fire Protection Code primarily focuses on fire prevention and safety standards, which, while important, does not encompass the full range of elements typically included in residential construction. The Mechanical Code regulates mechanical systems but does not address the entirety of building requirements for residential dwellings. Therefore, the International Residential Code is the most appropriate and relevant standard for detached one- and two-family dwellings.