Building regulations: Building regulations
United States: International Residential Code 2021
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- Category
- Building regulations: Building regulations
- Kind
- Regulation pack
- Languages
- None provided. The words are as the provider wrote them.
- Author
- CadCraft
- Version
- 6, published Oct 27, 2026 Published
The model code: numbers and section numbers entered from the IRC 2021 text in ICC's free viewer, checked 2026-10-27. A model code is not law until a state or city adopts it; pick your state's pack to check against what applies there.
License
CC0CC0 1.0 (public domain dedication). Anyone may use, change and share it for any purpose, with no conditions. Credit is welcome but not required.
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Regulation pack
Draft: entered from the published code, not yet reviewed by a professional. The model code: numbers and section numbers entered from the IRC 2021 text in ICC's free viewer, checked 2026-10-27. A model code is not law until a state or city adopts it; pick your state's pack to check against what applies there.
- Place
- United States
- Pack id
us-irc-2021- Edition
- IRC 2021
- Authority
- Model code
- Source date
- 2021-01
- Last checked
- 2026-10-27
- Source
- International Code Council, International Residential Code 2021
| Rule | Clause | Required |
|---|---|---|
| Riser height | R311.7.5.1 | At most 196.85 mm |
| Tread depth | R311.7.5.2 | At least 254 mm |
| Stair width | R311.7.1 | At least 914.4 mm |
| Stair headroom | R311.7.2 | At least 2,032 mm |
| Handrail height | R311.7.8.1 | 863.6 mm to 965.2 mm |
| Ceiling height Simplified: the code has exceptions for beams, sloped ceilings and basements. | R305.1 | At least 2,133.6 mm |
| Glazing, share of floor area Simplified: lighting by artificial means is allowed in some rooms. | R303.1 | At least 8 % of the floor area |
| Openable area, share of floor area Simplified: mechanical ventilation is allowed instead. | R303.1 | At least 4 % of the floor area |
| Habitable room floor area Every habitable room; kitchens are exempt. Floor under ceilings lower than 5 ft (sloped) or 7 ft (furred) does not count. | R304.1 | At least 6.503 m² (70 sq ft) |
| Habitable room least dimension In any horizontal direction; kitchens are exempt. | R304.2 | At least 2,133.6 mm |
| Hallway width | R311.6 | At least 914.4 mm |
| Egress door clear width One side-hinged egress door per dwelling unit; clear width with the door open 90 degrees (the checker estimates it as the leaf width less 2 in). | R311.2 | At least 812.8 mm |
| Egress door clear height Clear height from the top of the threshold to the bottom of the stop. | R311.2 | At least 1,981.2 mm |
| Escape opening net clear area Every sleeping room (and basements, habitable attics). Grade-floor openings may be 5.0 sq ft. The checker estimates the clear opening from the window type. | R310.2.1 | At least 0.53 m² (5.7 sq ft) |
| Escape opening clear width Net clear opening width. | R310.2.2 | At least 508 mm |
| Escape opening clear height Net clear opening height. | R310.2.2 | At least 609.6 mm |
| Escape opening sill height Measured from the floor to the bottom of the clear opening. | R310.2.3 | At most 1,117.6 mm |
| Wall outlets: farthest point from an outlet Measured along the floor line in each wall space 2 ft or wider, unbroken by doorways; kitchens, living, dining, family rooms, bedrooms and similar rooms. | E3901.2.1 | At most 1,828.8 mm |
| Switched lighting outlet | E3903.2 | At least 1 |
| Bathroom outlet The code asks for one within 36 in of each basin; the checker counts outlets in the bathroom. | E3901.6 | At least 1 |
| Laundry outlet | E3901.8 | At least 1 |
| Garage outlet One per vehicle bay. | E3901.9 | At least 1 |
| Hallway outlet (halls 10 ft or longer) | E3901.10 | At least 1 |
| Outdoor outlets (front and back) One at the front and one at the back, no higher than 6 ft 6 in above grade; the checker counts outlets outside the rooms. | E3901.7 | At least 2 |
| Smoke alarm in each sleeping room | R314.3 | At least 1 |
| Smoke alarm on each story Each story including basements; also outside each sleeping area. | R314.3 | At least 1 |
| Footing depth below grade Exterior footings, below undisturbed ground; at least the frost depth where the place gives one (R403.1.4.1). The checker takes the footing bottom less 6 in for the floor above grade. | R403.1.4 | At least 304.8 mm |
| Footing width At least 12 in; the size table for the loads, stories and soil (1500 psf presumed) can ask for more. | R403.1.1 | At least 304.8 mm |
| Footing thickness At least 6 in; the size table can ask for more. | R403.1.1 | At least 152.4 mm |
| Slab thickness Concrete floor slabs on ground. | R506.1 | At least 88.9 mm |
| Wall stud spacing From Table R602.3(5) by stud size and what the wall carries; the checker takes exterior walls as bearing. | Table R602.3(5) | At most 609.6 mm |
| Wall stud height Height between lateral supports, from Table R602.3(5) by stud size. | Table R602.3(5) | At most 3,048 mm |
| Header span From Table R602.7(1) (exterior bearing walls) by header plies and size, building width, floors above and ground snow load (30 psf column at least); the value shown is the table's largest span. The checker takes the clear span as the header length less 3 in. | Table R602.7(1) | At most 4,648.2 mm |
| Floor joist span From Table R502.3.1(2) (40 psf live load, living areas; sleeping areas may use the 30 psf table) by joist size and spacing, No. 2 lumber; the species is not recorded, so the lowest span of the four species is asked; the value shown is the table's largest span. Engineered (TJI) joists follow the make | Table R502.3.1(2) | At most 6,375.4 mm |
| Rafter span Table R802.4.1(1), 20 psf roof live, ceiling not attached, lowest species. Span = horizontal projection (sloped length x cos pitch). Not judged where ground snow is over 20 psf or the roof is trusses. | Table R802.4.1(1) | At most 7,924.8 mm |
| Ceiling joist span From Table R802.5.1(1) (uninhabitable attic without storage, 10 psf live) by joist size and spacing, No. 2 lumber, lowest of the species; the value shown is the table's largest span. | Table R802.5.1(1) | At most 7,924.8 mm |
| Exterior wall insulation R-value By climate zone (from the place criteria). Compares the insulation layers of each exterior wall type (nominal R) with the cavity and continuous options; no insulation layer is a note, not a pass. | N1102.1.3 | At least R-30 |
| Roof or ceiling insulation R-value Ceiling R-value by climate zone. The model records no roof insulation yet: shown as a note where the building has a roof. | N1102.1.3 | At least R-60 |
| Window U-factor Fenestration U-factor by climate zone. Windows carry no U-factor in the model yet: shown as a note where the building has windows. | N1102.1.3 | At most U-0.3 |
A guide only: the registered professional and the local authority decide. A pack holds numbers and clause numbers, never the standard's text. The Building regulations add-on in BimCraft checks drawings against it.
Versions
All versions| Drawing | Version | Change | License | Status | Published |
|---|---|---|---|---|---|
| Version 6 | DataUpdated from the add-on's pack (0d9874fc9322). | CC0 | Published | Oct 27, 2026 | |
| Version 5 | DataUpdated from the add-on's pack (9fb753138904). | CC0 | Published | Oct 27, 2026 | |
| Version 4 | DataUpdated from the add-on's pack (83c511359460). | CC0 | Published | Oct 27, 2026 | |
| Version 3 | DataUpdated from the add-on's pack (5a044d55311c). | CC0 | Published | Oct 27, 2026 | |
| Version 2 | DataUpdated from the add-on's pack (b5a7c368de82). | CC0 | Published | Oct 27, 2026 |
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