§ CODES International Residential Code
The IRC, in plain English.
The International Residential Code is the model code adopted (with amendments) by 49 of 50 states for one- and two-family dwellings. Entries span the 2018, 2021, and 2024 editions — translated into plain language and cross-referenced.
Entries covered
1,073
across all editions
Editions covered
IRC 2018–2024
3-year ICC release cycle
Chapters covered
42
in IRC 2024 (of 44 total)
States on IRC 2024
5 / 50
Adoption typically lags 2–4 years
§ 01 Editions & chapters
Pick an edition.
Editions release on a three-year cycle. State adoption typically lags by 2–4 years; check the state page to see which edition applies to your jurisdiction.
released Sep 2023 · adopted by 5 states
Chapter
Title
Scope
Entries
Chapter 1
Scope and Administration
Code applicability, AHJ authority, permits required, inspections framework.
8
→
Chapter 2
Definitions
Terms of art used throughout the code.
8
→
Chapter 3
Building Planning
Climate & geographic design criteria, occupancy, light & ventilation, means of egress, smoke alarms, AFCI/GFCI.
10
→
Chapter 4
Foundations
Footings, foundation walls, anchorage, dampproofing, drainage.
8
→
Chapter 5
Floors
Wood floor framing, concrete floors on ground.
8
→
Chapter 6
Wall Construction
Wood, cold-formed steel, ICF, masonry; bracing, fastening.
8
→
Chapter 7
Wall Covering
Interior & exterior coverings, lath & plaster, water-resistive barriers.
8
→
Chapter 8
Roof-Ceiling Construction
Rafters, ceiling joists, trusses, ventilation.
8
→
Chapter 9
Roof Assemblies
Underlayment, asphalt shingles, metal, tile, photovoltaic.
8
→
Chapter 10
Chimneys and Fireplaces
Masonry & factory-built, hearth extension, clearances.
8
→
Chapter 11
Energy Efficiency
Climate zones, R-values, fenestration, air leakage, ducts — major 2024 rewrite.
10
→
Chapter 12
Mechanical Administration
HVAC permits & inspection authority within IRC scope.
8
→
Chapter 13
General Mechanical System Requirements
Installation, access, listing & labeling, condensate.
8
→
Chapter 14
Heating and Cooling Equipment and Appliances
Furnaces, boilers, heat pumps, location, clearances.
8
→
Chapter 15
Exhaust Systems
Range hoods, dryer ducts, bath fans.
16
→
Chapter 16
Duct Systems
Materials, sealing, insulation, support.
8
→
Chapter 17
Combustion Air
Outdoor & combined-volume methods.
8
→
Chapter 18
Chimneys and Vents — Mechanical
Type B, masonry, listed venting, clearance.
8
→
Chapter 19
Special Fuel-Burning Equipment
Solid-fuel, fireplace stoves, sauna heaters.
6
→
Chapter 20
Boilers and Water Heaters
Sizing, T&P relief, expansion, seismic strapping.
6
→
Chapter 21
Hydronic Piping
Materials, joints, freeze protection.
6
→
Chapter 22
Special Piping and Storage Systems
Fuel oil, refrigerant access, leak detection.
6
→
Chapter 23
Solar Thermal Energy Systems
Collectors, freeze protection, sensors.
6
→
Chapter 24
Fuel Gas
Permitting framework for gas piping & appliances.
8
→
Chapter 25
Plumbing Administration
Permits, materials approval, inspection.
8
→
Chapter 26
General Plumbing Requirements
Installation, identification, fixture connections.
8
→
Chapter 27
Plumbing Fixtures
Bathtubs, lavatories, water closets, showers, accessibility.
10
→
Chapter 28
Water Heaters
Sizing, T&P, seismic, drain pans.
8
→
Chapter 29
Water Supply and Distribution
Sources, materials, sizing, backflow.
8
→
Chapter 30
Sanitary Drainage
Sizing, slope, materials, fixture units.
8
→
Chapter 31
Vents
Methods (cap, individual, common, wet, AAV).
14
→
Chapter 32
Traps
P-traps, prohibited traps, S-traps prohibited.
8
→
Chapter 34
General Electrical Requirements
Scope, identification, listing & labeling.
8
→
Chapter 35
Electrical Definitions
Terms used in electrical chapters.
8
→
Chapter 36
Services
Service capacity, equipment, working space.
8
→
Chapter 37
Branch Circuit and Feeder Requirements
Calculations, GFCI/AFCI requirements, conductors.
8
→
Chapter 38
Wiring Methods
Cable assemblies, raceway, fittings.
8
→
Chapter 39
Power and Lighting Distribution
Receptacle & lighting outlets per room.
10
→
Chapter 40
Devices and Luminaires
Switches, receptacles, lampholders, recessed.
8
→
Chapter 41
Appliance Installation
Required circuits, disconnects, kitchen appliances.
8
→
Chapter 42
Swimming Pools
Bonding, GFCI, equipment, lighting, signs.
8
→
Chapter 43
Class 2 Remote-Control, Signaling and Power-Limited Circuits
Doorbell, thermostat, low-voltage.
8
→
§ 02 Anatomy
What's in an entry.
Every entry follows the same shape: a citation header, plain-English body, key takeaways, an FAQ tied to the section, and links to related entries in the same chapter.
A · Citation
Section ID & chapter
Mono-set citation (e.g. IRC 2024 § R311.7) with parent chapter, edition, and section title.
B · Plain-English body
What the rule actually requires
Multi-section editorial body translating the code into language a homeowner, contractor, or inspector can read in under three minutes.
C · Key takeaways
The points to remember
A short numbered list of the rules a reader should walk away knowing — pulled into a sticky callout in the entry's right rail.
D · Field Q&A
Common questions, in context
Section-specific Q&A plus links to sibling entries in the same chapter.
§ 03 Common questions
About the codes.
Adoption, scope, and citation questions — answered once so each entry page doesn't have to.
01Which edition applies to my project?▸
The edition adopted by your state on the date your permit was issued (or, in some jurisdictions, the date of permit application). Check the state page for the current adopted edition. Some cities adopt local amendments on top of the state edition.
02Is this the official code text?▸
No. We publish editorial summaries and plain-English explanations alongside references to the official text. The official IRC is published by the International Code Council and is what an inspector enforces. Always cross-check against the official ICC publication for binding interpretation.
03Why aren't the IBC, IPC, IMC, or NEC here?▸
Coming. The IRC covers one- and two-family dwellings, which is most residential work and the bulk of homeowner traffic. The IBC (commercial), IPC (plumbing), IMC (mechanical), and NEC (electrical) are on the 2026 roadmap.
04Do you cover every section of every chapter?▸
Not yet. We publish entries for the sections that come up most often in field questions — currently 1,073 entries across 3 editions. Coverage expands as we triage homeowner and contractor questions; flag a gap at hi@jaspector.com.
05Can I cite Jaspector in a permit submittal?▸
Cite the underlying IRC section, not Jaspector. We exist to help you find and understand the section; the section itself is what carries weight with a plan-checker.
§ 04 Next