ICC R5 cheat sheet

Scope: the IRC governs detached one- and two-family dwellings and townhouses not more than three stories above grade plane with a separate means of egress, plus accessory structures.

Chapter 1 assigns duties: the building official enforces the code; the permit applicant is responsible for compliance of the submitted construction documents.

Permits are required for new construction, additions, alterations, and most structural, electrical, mechanical, and plumbing work; ordinary repairs and listed minor work are exempt.

Construction documents must show the extent and character of the work, and must be prepared and sealed by a registered design professional where the law requires.

Inspections required before concealment include foundation, framing, and rough-in; work may not be covered until inspected and approved.

A certificate of occupancy is issued only after the completed work is inspected and found to comply with the approved documents.

Board of appeals: an appeal of an official's interpretation is filed within the time stated in the local ordinance, and filing an appeal stays enforcement unless the official certifies immediate hazard.

Validity: a permit lapses if work does not commence within 180 days (or the locally adopted period) or is suspended or abandoned for 180 days.

Light, ventilation, and occupancy: every habitable room needs aggregate glazing area of at least 8 percent of floor area and openable area of at least 4 percent.

Ceiling height: habitable rooms, halls, and corridors require not less than 7 ft (2134 mm) clear; bathrooms, toilet rooms, and laundry rooms require 6 ft 8 in.

Egress: a dwelling unit must have at least one exit door, and every sleeping room must have at least one operable emergency escape and rescue opening.

Emergency escape opening sill height is not more than 44 in. above the floor; net clear opening is at least 5.7 sq ft (5.0 sq ft for grade-floor openings) with minimum width 20 in. and height 24 in.

Foundation footings: minimum width 12 in. and minimum thickness 6 in., bearing on undisturbed soil below the frost line; footing projections beyond the face of the wall are limited by table.

Frost-protected shallow foundations use a minimum footing depth per the frost-depth table plus insulation and drainage detailing; footing depth may not be less than the local frost line unless designed.

Story height above grade plane determines whether the building falls within the IRC: not more than three stories above grade plane.

Site grading: the ground within 6 in. of the foundation shall slope away at not less than 6 in. fall in the first 10 ft.

Floor joists: sawn-lumber spans are taken from the joist span tables and are limited by species/grade, size, spacing, and live load; notches in the top or bottom are limited to one-sixth of depth.

Bored holes in floor joists: diameter not more than one-third of joist depth, located not closer than 2 in. to the top or bottom edge and not in the middle third of the span where the hole diameter exceeds one-third.

Wall studs: size and spacing from the wall table; notching of exterior and bearing wall studs is limited to 25 percent of width, and boring to 40 percent of width.

Headers and lintels over openings are sized by span tables and must be supported by jack studs or an approved hanger; bearing length on wood or metal is at least 1 1/2 in.

Roof framing: rafters and ceiling joists are sized from span tables; rafter ties or a structural ridge resist thrust, and collar ties alone are not a substitute for rafter ties.

Rough sill and band joists must be anchored to the foundation with anchor bolts spaced not more than 6 ft on center, with at least two bolts per plate section and not less than 7 in. embedment.

Wood decay protection: wood in contact with the ground or in a crawl space must be naturally durable or preservative-treated; fasteners must be compatible with the treatment.

Trusses must be designed and installed per approved truss drawings; cutting, notching, or altering a truss member is prohibited.

The energy provisions require a building thermal envelope that limits heat loss and gain, with insulation installed in substantial contact with the surface it insulates and in full conformity with the labeled R-value.

Building thermal envelope values (R-values and U-factors) are set by climate zone; the same assembly has different requirements in zones 1 through 8.

Air leakage: the building thermal envelope must be sealed at penetrations, joints, and seams; recessed luminaires in the envelope must be sealed and rated for insulation contact.

Ducts and HVAC equipment located outside the conditioned space must be insulated and sealed; duct leakage testing applies where required by the adopted energy chapter.

Whole-house mechanical ventilation is required where the envelope is tightened; exhaust fans must vent to the outdoors, not into attics or crawl spaces.

Interior environment: bathrooms, toilet rooms, and kitchens require local exhaust; habitable rooms require natural or mechanical ventilation per the ventilation table.

Combustion air: fuel-burning appliances in a confined space require outdoor combustion air sized by the appliance input rating, or the space must be classified as unconfined.

Moisture control: a vapor retarder is required on the warm side of the assembly as specified, and crawl spaces must have a ground cover of at least 6-mil material.

Smoke alarms: required in each sleeping room, outside each sleeping area in the immediate vicinity, and on each additional story including basements; they must be interconnected.

Smoke alarm power source: primary power from the building wiring with battery backup, or a listed battery-only alarm where permitted for existing or non-remodeled dwellings.

Carbon monoxide alarms are required outside sleeping areas and on each story where the dwelling contains a fuel-burning appliance or an attached garage.

Fire separation: a one-hour fire-resistance rating is required between a dwelling unit and an attached private garage, and between townhouse units, with doors of at least 20-minute rating.

Egress doors must be side-hinged, at least 32 in. clear width, and at least 6 ft 8 in. tall; the required exit door must be readily openable from the inside without a key or tool.

Egress window wells: where an emergency escape opening is below grade, a ladder or steps and a minimum well area and horizontal projection are required.

Fireblocking is required at concealed spaces: between floor and ceiling, at the top and bottom of stair stringers, and at penetrations through wall and floor assemblies.

Draftstopping is required in concealed attic and floor spaces to limit the horizontal spread of fire; the maximum area of a draftstopped space is specified in the fire chapter.