Free ICC B1 Exam Flashcards

The model IRC covers detached one- and two-family dwellings, townhouses with separate means of egress, and associated accessory structures, within its limit of three stories above grade plane. Check the scope exceptions and local adoption separately (R101.2).

The building official interprets and enforces the adopted code, administers permits and inspections, and issues certificates of occupancy where appropriate (R104, R105, R109 and R110).

Keep the top level. Step the footing when its top elevation must change or when its bottom would slope more than 1 vertical to 10 horizontal (R403.1.5).

High water tables or other severe soil-water conditions trigger waterproofing for walls retaining earth and enclosing below-grade interior space (R406.2).

Wait for adequate wall strength and for the wall to be anchored to the floor above or adequately braced. R404.1.7 excepts bracing for walls holding less than 4 feet of unbalanced fill.

The general minimum is 7 feet for habitable space and hallways, and 6 feet 8 inches in bathrooms, toilet rooms and laundry rooms. Check the exceptions in 2024 IRC R313.1.

Under 2024 IRC R312, a habitable room generally needs at least 70 square feet and at least 7 feet in any horizontal dimension; kitchens are excepted. There is no separate 120-square-foot room minimum in this rule.

The default glazed area is 8% of the floor area served (2024 IRC R325.1.1). Before substituting artificial lighting, check the conditions for the applicable exception, including ventilation.

No. R502.8.2 permits cuts only as allowed by the manufacturer or where their effects were specifically considered in the member design by a registered design professional.

A hole over 40% and up to 60% of the stud depth normally requires doubling; no more than two successive doubled studs may be bored this way. Check the approved stud-shoe exception (R602.6).

Use the number of jack studs or an approved framing anchor required by the applicable header table. The adjacent full-height studs have their own requirements (R602.7.5).

Provide full bearing on a nominal 2-by or larger sole plate or sill that is at least as wide as the studs (R602.3.4).

Normally at least 5.7 square feet, or 5.0 for a grade-floor opening. The width and height must independently reach 20 inches and 24 inches. Those two minima alone give 480 ÷ 144 = 3.33 square feet (R319.2).

Check the product identification required by the AISI standard referenced in R603.2.4. A wood lumber grade stamp does not apply to this framing.

The bottom of the clear opening may be no more than 44 inches above the floor (2024 IRC R319.2.3). An exterior area-well ladder addresses well depth separately.

The nearest panel edge is generally within 10 feet of each end of the line and adjacent panel edges are generally no more than 20 feet apart. Check the exceptions in R602.10.2.2.

Lap upper flashing over lower flashing so water drains outward, rather than reaching the wall cavity (R703.4).

Immediately above the flashing in the outside wythe, no more than 33 inches on center, with at least 3/16-inch diameter (R703.8.6).

7-3/4 inches maximum for a conventional stair; measure vertically between leading edges of adjacent treads (2024 IRC R318.7.5.1).

10 inches minimum, measured horizontally between the vertical planes of the foremost projection of adjacent treads. Winder treads must be at least 10 inches at the walk line and never less than 6 inches at any point.

Place it at least 4 inches above earth or 2 inches above pavement, at or below the foundation plate line (R703.7.2.1).

Match the material to Table R702.4.2 and install it according to the manufacturer’s instructions. The visible finish cannot establish that the backer is suitable.

Use the horizontal projection, not the sloped length along the rafter. Choose the applicable R802.4.1 table for loading, grade, spacing and other conditions.

R802.10.4 requires approval from a registered design professional before a truss member is cut, drilled, notched or otherwise altered.

Handrails are required on at least one side of any stairway with four or more risers. (Three or fewer risers do not require a handrail unless otherwise mandated by other provisions.)

2:12 under R905.2.2. Below 4:12, consult the applicable low-slope underlayment provisions before approving the roof.

For listed roof coverings in areas designated for a history of eave ice and backed-up water, R905.1.2 generally extends the barrier at least 24 inches inside the exterior wall line. Check exceptions and slope details.

Provide a guard if the vertical drop exceeds 30 inches at any point within 36 inches horizontally of the open edge. Normal guard height is at least 36 inches; the open side of a stair can be 34 inches (2024 IRC R321.1).

The general limit excludes a 4-inch sphere. Stair guards exclude a 4-3/8-inch sphere, and their riser/tread/bottom-rail triangle excludes a 6-inch sphere (2024 IRC R321.1.3).

Footings must be sized to the IRC tables based on soil bearing and load; minimum concrete footing thickness is 6 inches, and footing projection beyond the foundation wall must be at least 2 inches but not more than the footing thickness.

Extending below the local frost line is one option; R403.1.4.1 also lists frost-protected designs and solid rock. The general exterior footing minimum is 12 inches below undisturbed ground; check the applicable frost rules and exceptions.

Table R402.2 generally requires 2,500 psi at 28 days for concrete not exposed to weather. Choose the actual minimum by element and weathering exposure; some exposed slabs require up to 3,500 psi.

Sill plates must be anchored with 0.5-inch-minimum-diameter anchor bolts (or approved straps) spaced not more than 6 feet on center, embedded at least 7 inches into concrete or grouted masonry.

In the standard R403.1.6 bolt layout, use at least two per plate section, with a bolt 7 bolt diameters to 12 inches from each end. For a 1/2-inch bolt, 7 diameters equals 3-1/2 inches.

A vented crawl space generally needs 1 square foot of net open vent area per 150 square feet. An approved Class I ground retarder permits 1:1,500 under R408.2. R408.3 sets separate requirements for unvented spaces.

Within a crawl space, R304.1 requires naturally durable or preservative-treated wood for joists closer than 18 inches, girders closer than 12 inches, and columns closer than 8 inches to exposed ground.

Joists must bear at least 1.5 inches on wood or metal and at least 3 inches on masonry or concrete. Inadequate bearing is a frequently cited framing inspection defect.

Ordinary notches cannot exceed 1/6 of member depth or 1/3 of depth in length; none in the middle third. End notches may be up to 1/4 depth. The tension side of a member at least nominal 4 inches thick can be notched only at its ends (R502.8.1).

Hole diameter is limited to 1/3 of member depth. Keep holes at least 2 inches from top and bottom edges, other holes and notches (R502.8.1).

Floor members have an L/360 deflection limit under the applicable live load (Table R301.7). A 15-foot span is 180 inches, so 180 ÷ 360 = 1/2 inch.

Exterior and bearing studs: up to 25% notch depth; boring over 40% through 60% requires doubling under the standard rule. Nonbearing partitions: up to 40% notch depth and 60% hole diameter (R602.6).

Keep at least 5/8 inch from the hole edge to the stud edge and do not bore through a notch section. For an exterior or bearing stud hole over 40% through 60%, double the stud; no more than two successive doubled studs may be bored this way (R602.6).

Use the applicable R602.7 table for the opening and supported load. Check the table’s assumptions and required supports; a fixed two-ply size does not fit every opening.

Connections such as joist-to-sill, top plate laps, stud-to-plate, and sheathing nailing are governed by the IRC fastening schedule table. On the open-book exam, locating Table R602.3(1) quickly is more valuable than memorizing every value.

R802.6 generally requires 1-1/2 inches of bearing on wood or metal or 3 inches on masonry or concrete. Without continuous ties, R802.3 requires the ridge to be supported by a wall or a designed ridge beam.

The default is 1:150 net free vent area. R806.2 permits 1:300 if the upper/lower vent distribution is met and, in Climate Zones 6–8, the warm side has a Class I or II vapor retarder.

Where the attic has at least 30 inches of vertical height over at least 30 square feet, the required rough opening is at least 22 by 30 inches (R807.1).

It interrupts concealed draft paths. R302.11 calls for fireblocking at floor and ceiling levels and horizontally at intervals of no more than 10 feet in concealed stud or partition spaces.

Table R302.6 generally calls for at least 1/2-inch gypsum board or equivalent on the garage side and 5/8-inch Type X or equivalent below habitable rooms. R302.5.1 separately governs door openings.

Smoke alarms go in each sleeping room, outside each separate sleeping area, and on the applicable stories. CO alarms go outside sleeping areas when a fuel-fired appliance or a communicating attached garage triggers the rule, and in a bedroom if it or its attached bath contains a fuel-burning appliance (2024 IRC R310–R311).