2021 International Residential Code (ICC IRC-2021) | Essential Standards for Home Construction | International Code Council

The 2021 IRC is a comprehensive, stand-alone residential code that creates minimum regulations for one- and two-family dwellings of three stories or less. It brings together all building, plumbing, mechanical, fuel gas, energy, and electrical provisions for one- and two-family residences.

The International Code Council (ICC) publishes the IRC.

The IRC is updated every three years. The 2021 edition is the most recent version.

The IRC applies to detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress.

The IRC becomes legally binding only when adopted by a jurisdiction (state, county, city) as their building code.

Check with your local building department or visit the ICC's adoption page for information on code adoption by state.

Yes, jurisdictions can amend the IRC to suit local conditions. Always check with your local building department for any local amendments.

Key changes include:

• New provisions for energy storage systems
• Updated requirements for deck construction
• Changes to emergency escape and rescue opening requirements
• New provisions for tiny houses

Yes, the 2021 IRC includes updated energy provisions aligned with the 2021 International Energy Conservation Code (IECC).

Habitable rooms must have a floor area of at least 70 square feet, with no dimension less than 7 feet (except kitchens).

Generally, habitable spaces must have a ceiling height of not less than 7 feet. There are exceptions for bathrooms, laundry rooms, and basements.

Basements, habitable attics, and every sleeping room must have at least one operable emergency escape and rescue opening. The 2021 IRC includes updated provisions for these openings.

Yes, the IRC provides details on reinforcement, thickness, and vapor retarders for slab-on-ground foundations.

Span tables in the IRC help determine the required size and spacing of joists, rafters, and beams based on the loads they must support.

Yes, the IRC provides detailed requirements for wood frame construction, including studs, joists, rafters, and sheathing.

Roof coverings must be installed in accordance with the manufacturer's instructions and the IRC. The code specifies requirements for different roofing materials.

Yes, in areas where there has been a history of ice forming along the eaves, an ice barrier is required and must extend from the lowest edges of all roof surfaces to a point at least 24 inches inside the exterior wall line of the building.

The IRC provides detailed requirements for the construction of masonry chimneys and fireplaces, including clearances, flue lining, and hearth extensions.

The IRC includes requirements for electrical system sizing, grounding, wiring methods, and device and luminaire locations. It also mandates GFCI and AFCI protection in specific locations.

The IRC covers water supply and distribution, sanitary drainage, vents, and fixtures. It specifies pipe sizing, materials, and installation methods.

The IRC provides requirements for HVAC equipment sizing, duct systems, combustion air, and venting of fuel-burning appliances.

The IRC includes provisions for insulation, fenestration, air sealing, and equipment efficiency. These align with the International Energy Conservation Code (IECC).

The IRC includes provisions for additions, alterations, and repairs to existing structures. However, many jurisdictions have separate existing building codes.

Yes, the 2021 IRC includes Appendix Q, which provides specific provisions for tiny houses (400 square feet or less in floor area excluding lofts).