International Residential Code for One- and Two-Family Dwellings ICC IRC standard 2021

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International Residential Code for One- and Two-Family Dwellings

ICC IRC-2021  

standard by International Code Council, 2021



The 2021 International Residential Code for One- and Two-Family Dwellings is a series of regulations that establishes minimum standards for how homes are built. The code establishes how homes are built, but also how they are designed and the types of materials that can be used. The code is broken down into six parts, and each part has its own chapter. The first part covers general provisions, the second part covers construction, the third part covers electrical, the fourth part covers mechanical, the fifth part covers plumbing, and the sixth part covers energy conservation. The code establishes requirements for every aspect of building a home, from where the septic tank is located to how many outlets are in the bedroom. The 2021 International Residential Code for One- and Two-Family Dwellings is an essential tool for anyone who is planning to build a home.


This comprehensive code comprises all building, plumbing, mechanical, fuel gas and electrical requirements for one- and two-family dwellings and townhouses up to three stories. The 2021 IRC® contains many important changes such as:

  • Braced wall lines must be placed on a physical wall or placed between multiple walls.
  • The rated separation for two-family dwellings is 1 hour whether or not a lot line exists between units.
  • Emergency escape and rescue openings require a clear 36-inch-wide path to a public way.
  • An engineered design is required for storm shelters.
  • A habitable attic is limited to one-half the area of the story below and the dwelling requires sprinklers.
  • Updated Wind Speed maps match IBC and ASCE 7 maps.
  • Deck design now considers snow load, tributary area for footing and post height, and guard details.
  • Specific requirements for deck guardrails were added.
  • Component and cladding wind pressures in Table R301.2(2) are updated for new design wind speeds and hip or gable roof profiles.
  • Minimum footing size tables are revised to more accurately reflect current practice.
  • Cripple wall requirements apply only to exterior cripple walls.
  • New appendices for cob construction and 3D printed construction are added.
  • A 30 percent reduction of airflow is permitted for balanced ventilation systems.
  • Commercial gas cooking appliances are prohibited.
  • The head pressure for a water test of DWV systems increased to 10 feet.
  • Air vacuum testing is now permitted for plastic piping DWV systems.
  • Section P2904 for dwelling sprinklers is expanded to more closely align with NFPA 13D.
  • An emergency service disconnect is required in a readily accessible outdoor location.
  • A surge-protective device (SPD) is now required at the service panel.
  • The number of receptacle outlets required for peninsular and island countertops in kitchens is determined by the area of the countertop surface.
  • GFCI protection is now required for damp and wet locations not included in the other 10 areas requiring GFCI protection.

The 2021 IRC® Redline is still in development and you will received an updated PDF once completed.


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  • 5
    Latest code book

    Posted by Tyrone S. on Jan 4th 2023

    Great for keeping up on current building codes

  • 5
    Excellent and fast

    Posted by Eric G. on Dec 16th 2021

    Excellent and fast. I am very happy with my purchase and would recommend to anyone!!

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