Which type of dwellings must comply with the requirements in the International Residential Code?

The correct answer includes all the specified types of dwellings: detached one-family dwellings, detached two-family dwellings, and multiple single-family dwellings. The International Residential Code (IRC) is designed to establish minimum regulations for residential buildings to ensure safety and livability.

Detached one-family dwellings are explicitly covered by the IRC, as they focus on individual homes. Detached two-family dwellings, often referred to as duplexes, must also comply with IRC regulations, as they possess unique safety and structural considerations. Furthermore, multiple single-family dwellings can refer to structures that, while housing separate families, function as a single building with shared elements, which also fall under the guidelines of the IRC.

In essence, the IRC aims to standardize construction practices and safety measures across a range of residential structures, which is why all these types of dwellings are included. By doing so, it ensures consistency in construction quality that protects both occupants and the broader community.