The 2024 International Residential Code (IRC) is a comprehensive standard encompassing all building, plumbing, mechanical, fuel gas, and electrical requirements for one- and two-family dwellings and townhouses up to three stories in height. This edition introduces several significant updates to enhance safety, consistency, and modern building practices: Wall Bracing and Separation: Braced wall lines must now align with physical walls or be placed between multiple walls. Two-family dwellings require a 1-hour fire-resistance-rated separation—regardless of whether a lot line exists between units.209