EstatePass

Building Planning — ICC B1 Practice Questions

44 questions · 8% of the ICC B1 exam

Worked questions

1. Under the 2021 IRC two-family dwelling provisions described by ICC, which statement correctly describes the separation rating between the two dwelling units? Consider the baseline and the reduction for a qualifying dwelling sprinkler system installed throughout.

  • AEvery duplex separation always requires two hours
  • The baseline is one hour; a qualifying system under Section P2904 or NFPA 13D can permit a half-hour separation
  • CTwo independent stud walls eliminate the need for a rating
  • DOnly horizontal separation is regulated

Where to look it up

https://www.iccsafe.org/building-safety-journal/bsj-technical/significant-changes-to-two-family-dwelling-separation-in-the-2021-international-residential-code/

Why B is correct

ICC explains a one-hour baseline for two-family dwelling separation. In the 2021 IRC, a qualifying dwelling sprinkler system under P2904 or NFPA 13D can support reduction to one-half hour. This is edition-specific; the article distinguishes the earlier full NFPA 13 condition. A change still needs an approved assembly and applicable project approval, not merely a lighter wall chosen onsite.

2. Below the ceiling line the rated separation is intact, but in the attic the framers stopped the assembly at the top of the ceiling joists and left the space above open across the unit line. What should the inspector require?

  • ANothing, because the attic space above the ceiling line falls outside the required separation

    The attic is expressly inside the required separation. The rating is not allowed to stop at the ceiling line.

  • BDraftstopping material only, because a rated assembly is not required above a ceiling

    Draftstopping limits the spread of fire within concealed spaces and carries no fire-resistance rating. It is not a substitute for continuing a rated assembly.

  • CThat the opening be closed with unfaced batt insulation packed tight against the framing

    Insulation of any type provides no fire-resistance rating and will not close the assembly. Packing the gap gives the appearance of a seal with none of the performance.

  • That the rated separation be continued from the foundation to the underside of the roof sheathing

Why D is correct

A townhouse separation has to be continuous, running from the foundation all the way to the underside of the roof sheathing, with the joint between the wall and the deck closed. An attic that is open over the top of the wall gives fire an unobstructed path from one unit into the next, which defeats the entire separation regardless of how well the wall below was built.

What this question is testing

The item tests whether the candidate understands that a fire-resistance-rated separation must be continuous through concealed spaces, and whether the candidate can distinguish draftstopping from a rated assembly.

On the job

Attics are inspected last, poorly lit, and full of trusses that make sighting down the wall line difficult. This is where separation walls get abandoned, especially where the truss profile changes or a mechanical unit sits over the party wall. Carry a light and walk the full length of the wall on both sides of the unit line. The other frequent finding is a properly built wall with a two-inch gap at the roof deck that nobody thought to close.

Memory technique

Fire goes over the top. A wall that stops at the ceiling is a wall with a door in it.

Exam tip

Follow a rated wall with your finger from the footing to the roof deck. Wherever it stops, that is the answer.

Where to look it up

IRC Chapter 3, Section R302.2 for townhouses, and R302.12 for draftstopping, which is a separate requirement.

3. For this bedroom area check, use a specified minimum floor area of 70 square feet and minimum horizontal dimension of 7 feet. The room is 8 by 8 feet with full required ceiling height. Which finding follows from these two criteria?

  • It fails the area criterion: 64 square feet is below 70
  • BIt passes both criteria because both dimensions exceed 7 feet
  • CIt fails because the supplied area minimum is 100 square feet
  • DOnly the total dwelling area matters

Where to look it up

Explicit exercise assumptions; not a universal code requirement.

Why A is correct

Area = 8 × 8 = 64 square feet, 6 below the supplied minimum. Both horizontal dimensions exceed 7 feet, but that does not cure the area deficiency. This is a check against the stated criteria; simply relabeling a room does not establish that its actual use or applicable requirements have changed.

4. In a newly finished basement, the family-room ceiling is 7 feet high, with 6 feet 6 inches of clearance under one girder. The bathroom ceiling is uniformly 6 feet 10 inches high, including its shower-use area. Considering only 2021 IRC R305.1’s ceiling-height requirements, which finding is correct?

  • AThe girder necessarily violates a 7-foot minimum at every point
  • BBoth the girder and bathroom necessarily violate a universal 7-foot minimum
  • Neither stated height is deficient: the habitable ceiling, basement girder exception and bathroom minimum are satisfied
  • DEvery basement space has a universal 6-foot-8-inch minimum with no obstruction exceptions

Where to look it up

https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

Why C is correct

R305.1 requires 7 feet for habitable space and 6 feet 8 inches for bathrooms, toilet rooms and laundry rooms. Exception 3 allows beams, girders, ducts and other obstructions in basements containing habitable space to extend down to 6 feet 4 inches. Thus the 7-foot family-room ceiling, 6-foot-6-inch girder clearance and 6-foot-10-inch bathroom ceiling pass these stated height checks. The showerhead area has its own 30-by-30-inch minimum-area height condition; the question states the same bathroom height there. This finding does not approve unrelated aspects of the work. Source: https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

5. A garage below a bedroom has the required 5/8-inch Type X ceiling separation and the required wall separation. Steel beams and columns supporting that floor-ceiling assembly are exposed with no equivalent protective covering. Under 2021 IRC Table R302.6, what protection is required on those supporting members?

  • At least 1/2-inch gypsum board or equivalent
  • BNone, because steel is noncombustible
  • CNone, because only ceiling and wall membranes are regulated
  • DOnly 5/8-inch Type X gypsum board is permitted, with no equivalent option

Where to look it up

https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

Why A is correct

Table R302.6 separately lists structures supporting the floor-ceiling assemblies used for the required separation. Their minimum protection is 1/2-inch gypsum board or equivalent. Noncombustible steel is not an exemption from this table row. The ceiling beneath habitable rooms has its own 5/8-inch Type X-or-equivalent row. R302.6 directs gypsum attachment to Table R702.3.5; this question does not establish a fastening violation from an unspecified screw pattern or predict an appeal outcome. Source: https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

6. A bathroom uses 2021 IRC R303.3’s window-based light and ventilation option. Its only window has 4 square feet of fixed glazing and no openable portion. No artificial-light-and-local-exhaust alternative is provided. What is the finding?

  • AThe total glazing area alone makes it compliant
  • It fails the openable-window requirement despite adequate total glazing
  • CThe interior bathroom door substitutes for openable exterior glazing
  • DIt fails because every bathroom must use the habitable-room 8-percent glazing rule

Where to look it up

https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

Why B is correct

R303.3 requires at least 3 square feet of aggregate window glazing, one-half of which is openable. Four square feet of entirely fixed glass supplies no openable area, so it fails this selected route. The exception is not simply “add any fan”: it requires artificial light and local exhaust meeting M1505, discharged directly outdoors. Bathroom identity and the chosen compliance route are now explicit; the habitable-room percentage is not the bathroom-specific rule. Source: https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

7. The ceiling joists were sized from the table column for an uninhabitable attic with limited storage at 20 pounds per square foot, and the stair is now framed and finished. How should the inspector judge the framing?

  • AAccept it; the stair affects how the attic is reached and not the load the framing has to be designed for

    Access is exactly what the table keys on. A fixed stair changes how a space gets used, and the table assigns a higher load for that reason.

  • BAccept it; the limited storage column already accounts for occasional foot traffic during maintenance

    The limited storage value contemplates occasional light storage in a space reached by a hatch or a pull-down. It is not the value the table assigns once a fixed stair is provided.

  • Reject it; an attic served by a fixed stair is designed for 30 pounds per square foot, so the joists must be rechecked
  • DReject it; an attic reached by a fixed stair becomes a habitable room and must meet the ceiling height requirements

    A fixed stair does not by itself make the attic habitable; habitable space brings ceiling height, light, ventilation and egress requirements that follow from finishing the space, not from the stair. The immediate issue is the design load.

Why C is correct

The live load table gives attics served by fixed stairs 30 pounds per square foot, against 20 for an uninhabitable attic with limited storage. Adding the stair changed the governing load, so the joists must be rechecked against the higher value and reinforced if the span no longer works.

What this question is testing

Whether the candidate can read the live load table by how a space is accessed and used, recognizes that a field change to access can change the governing load, and knows the correct response is to recheck the framing.

On the job

Owners add attic stairs all the time, sometimes under a permit for something else and sometimes with none at all. Inspectors who see a new stair look at what the ceiling joists were sized for, which means going back to the plans. The correction is usually sistering the joists or adding a beam, and it is far easier before the attic is floored and filled.

Memory technique

Give an attic a stair and it fills up.

Exam tip

The live load table treats attics by access. A fixed stair moves it to 30 pounds.

Where to look it up

IRC Chapter 3, design criteria, the live load table with its attic entries.

8. For a natural-ventilation area check, an 11-by-12-foot bedroom must provide openable area of at least 4 percent of floor area. The clear opening is 30 by 26 inches; the rough opening is 34 by 62 inches. Does the clear opening meet the stated area requirement?

  • ANo: the required openable area is 10.56 square feet
  • BNo: the openable area must equal all glazing
  • CYes: use the rough-opening area
  • Yes: the clear area is about 5.4167 square feet, exceeding 5.28

Where to look it up

Explicit exercise assumptions; not a universal code requirement.

Why D is correct

Required area = 11 × 12 × 0.04 = 5.28 square feet = 760.32 square inches. Actual clear area = 30 × 26 = 780 square inches = 5.416666... square feet. The margin is 19.68 square inches. This passes only the supplied ventilation-area check; rough-opening area is not credited and other bedroom requirements are separate.

9. For this approved-plan comparison, the stated prescriptive limits are 10 feet of laterally unsupported bearing-wall stud height and no more than 16 inches of floor-framing depth. Actual unsupported stud height is 12 feet, with 14-inch floor framing. No alternative design has been approved. What follows?

  • The stud-height limit is exceeded; the supplied prescriptive basis does not approve this wall
  • BThe wall passes because floor depth is below 16 inches
  • CSheathing automatically waives the stated stud-height limit
  • DDoubling studs automatically waives the stated stud-height limit

Where to look it up

Explicit exercise assumptions; not a universal code requirement.

Why A is correct

The unsupported stud height exceeds the supplied limit by 12 − 10 = 2 feet. The 14-inch floor framing meets its separate 16-inch limit but cannot offset excessive stud height. Resolve the discrepancy through an applicable approved design or compliant revision. These supplied limits are not universal limits for every wood wall.

10. A dwelling address is spelled out in 3-inch brass script characters against a matching brass plate. Under 2021 IRC R319.1, what is required instead?

  • ACharacters at least 3 inches high, with street visibility optional
  • BOnly 6-inch internally illuminated numbers are permitted
  • Approved identification using Arabic numbers or alphabetical letters without spelling out numbers, at least 4 inches high with a 1/2-inch stroke, contrasting and visible from the fronting street
  • DIdentification must always be moved exclusively to a mailbox

Where to look it up

https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

Why C is correct

R319.1 requires legible, contrasting identification visible from the street or road fronting the property. It sets a 4-inch character height and 0.5-inch minimum stroke and prohibits spelling out numbers. The stated 3-inch, matching-color, spelled-out treatment fails those specified requirements. Distance from the street alone does not establish invisibility, and no hedge or measured stroke failure is assumed. The section also addresses additional approved locations and a monument, pole or other sign where private-road access prevents viewing the address from the public way. Source: https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

11. The site is established as a windborne debris region under the adopted 2021 IRC criteria. Exterior windows have a sufficient wind-pressure rating but no impact qualification and no compliant opening protection is provided. Under R301.2.1.2, what is the finding?

  • AWind-pressure rating alone satisfies debris-impact protection
  • BOnly windward windows require protection
  • COnly upper-story windows require protection
  • The exterior glazing requires compliant windborne-debris protection; pressure rating alone does not establish it

Where to look it up

https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

Why D is correct

R301.2.1.2 requires exterior glazing in a windborne debris region to have debris protection meeting the referenced impact requirements. Pressure resistance and debris impact are different evaluations. The section has a separate garage-door glazing standard and an express route for qualifying wood structural panels with stated thickness, span and attachment conditions. Therefore plywood is not categorically excluded, but a loose uninstalled panel is not proof of compliance. The question states that no compliant protection is present; neither a windward-only nor an upper-story-only exemption cures that. Source: https://codes.iccsafe.org/content/IRC2021P1/chapter-3-building-planning

33 more in the bank

Answers and explanations for these are in the app.

  • The side wall of the house sits 2 feet 6 inches from the lot line, and the framers have roughed in two bedroom windows in that wall. The dwelling has no automatic sprinkler system. What is the correct call?
  • The garage side of the common wall is covered with half-inch gypsum board, the garage ceiling under the bedroom is covered with the same half-inch board, and the door from the garage into the house is a hollow-core wood slab 1 and three-quarter inches thick. What must the inspector cite?
  • The finished ground surface next to the foundation falls only 2 inches over the first 10 feet away from the wall, and there is no swale, drain or other approved means of carrying water away. What does the IRC require here?
  • The base flood elevation for the site is 12 feet and the design flood elevation is also 12 feet. The builder set the lowest floor of the dwelling at exactly 12 feet, matching the map. How should the inspector rule under the IRC?
  • The room contains a tub and a toilet, and the ventilation is a ceiling exhaust fan rated at 30 cfm operated by a wall switch, discharging to the outdoors. How should the inspector rule?
  • The room measures 14 feet by 18 feet. Its only glazing is a fixed unit with 12 square feet of glass and a casement with 6 square feet of glass, and no artificial lighting alternative was approved on the plans. What does the inspector find?
  • The bedroom measures 12 feet by 15 feet. It has two double-hung windows, each with 15 square feet of glazing, and each sash opens to expose half of that glazing. No whole-house mechanical ventilation alternative is shown on the approved plans. What does the inspector find?
  • The drawings show one building holding three attached dwelling units side by side. Each unit is four stories above grade plane, each has its own separate means of egress directly to the outside, and each is separated from the next by a wall running from the foundation to the roof along a property line. Which statement correctly describes how the project is governed?
  • In this row the floor joists of one unit bear on a ledger fastened to the wall framing that belongs to the adjacent unit, and the roof framing of one unit is carried on the top plate of its neighbor's wall. The common wall itself is a single assembly with the required fire-resistance rating. How should the inspector rule?
  • The side wall stands 4 feet from the lot line used to determine fire separation distance. The wall measures 40 feet long by 9 feet high, and the framers have roughed in window and door openings totaling 92 square feet. At this fire separation distance the maximum permitted area of openings is 25 percent of the wall area. How should the inspector rule?
  • The new dwelling sits 40 feet from every property line, but only 5 feet from the existing dwelling standing on the same lot. The contractor argues that fire separation distance is measured to the property line, so the wall facing the existing house needs no rating and carries no limit on openings. How should the inspector respond?
  • Between the finished faces of the knee walls the space will be 6 feet 6 inches across, and it runs 12 feet the other way, so the floor area works out to 78 square feet. Full required ceiling height is available throughout that footprint, and the plans label the space a bedroom. The minimum floor area for a habitable room is 70 square feet and the minimum horizontal dimension is 7 feet. How should the inspector rule?
  • The new basement bathroom has 6 feet 10 inches of clear height over most of the room, dropping to 6 feet 6 inches beneath a duct soffit that crosses the room, and the soffit passes directly over the shower so that the clear height at the shower head position is also 6 feet 6 inches. The minimum ceiling height in a bathroom, toilet room or laundry room is 6 feet 8 inches, and that height must be provided over the shower head area. How should the inspector rule?
  • The new family room is fully below grade with no glazing of any kind. The owner has installed recessed lighting throughout and asks whether the room can be approved without any glazed area. Leaving the emergency escape and rescue requirement aside, what does the light requirement permit here?
  • The study measures 13 feet by 16 feet with an 8-foot ceiling, and none of its windows open. The mechanical alternative to natural ventilation calls for an outdoor air supply capable of 0.35 air change per hour in the room, but not less than 15 cubic feet per minute of outdoor air per occupant, and the room is designed for two occupants. What is the minimum required outdoor air supply?
  • The lowest floor is elevated above the design flood elevation as the plans require. Below it, the builder has enclosed the pier area with framed walls and gypsum board, fitted a solid entry door, and finished the space as a hobby room. There are no openings of any kind to let floodwater in or out of the enclosure. How should the inspector rule?
  • The unit has a kitchen sink, a water closet and a lavatory, all connected to an approved water supply and drainage system. It has no bathtub and no shower, and the owner explains that the occupants will use the bathroom in the main house 40 feet away. How should the inspector rule?
  • The approved site plan shows the front wall of the house 25 feet from the front lot line and the side wall 8 feet from the side line. Measuring from the surveyor's pins, you find the forms sit 25 feet off the front but 6 feet 3 inches off the side line. The excavator explains that he shifted the hole over to save a large tree. What is the appropriate inspector response?
  • The adopted table gives an ultimate design wind speed of 130 miles per hour for this jurisdiction, and the designer's notes state that the house was designed for 115 miles per hour, citing a regional map. How should the inspector or plan reviewer treat this?
  • The space is insulated and finished, the electrical is complete, and no heating equipment of any kind serves it; the owner intends to use a portable plug-in heater. How should the inspector judge this?
  • The water closet flange is set with its centerline 13 inches from the finished face of the side wall, and 20 inches of clear space in front of the bowl to the opposite wall. How does this layout stand?
  • The exhaust fan is rated at 80 cubic feet per minute and switched at the door, and its flexible duct runs 6 feet into the attic and simply ends there, discharging above the insulation. How should the inspector judge this?
  • The structure is roofed, its long side facing the driveway is open, and the three remaining sides have been framed and sheathed with siding, with a service door in the rear wall. How should the inspector classify and judge it?
  • The set shows the required separation between units and no automatic fire sprinkler system anywhere in the row, and the designer states that sprinklers are optional for residential construction. How should the plan reviewer respond?
  • The room measures 12 feet by 14 feet. The window's sash gives a net clear opening of 5.9 square feet and its total glazed area is 9 square feet, and natural light requires glazing of not less than 8 percent of the floor area. Does the room comply for light?
  • The house is 2,400 square feet with three bedrooms, and the ventilation rate is figured as 0.01 times the floor area plus 7.5 times the number of bedrooms plus one. What continuous rate does this house require?
  • The only glazing proposed for the room is a fixed unit with 14 square feet of glass, and natural light requires a glazed area of not less than 8 percent of the floor area. No artificial lighting alternative is shown on the plans. What is the largest floor area this room may have and still be approved for natural light on that glazing alone?
  • The room measures 15 feet by 16 feet. Its windows give a combined 20 square feet of glazing, of which 8.5 square feet is openable. Natural light requires glazed area of not less than 8 percent of the floor area and natural ventilation requires openable area of not less than 4 percent, and no mechanical alternative is shown on the approved plans. What is the finding?
  • The bathroom measures 7 feet by 10 feet. Its only opening is an awning window with 4 square feet of glazing, and the sash swings out to leave 2.5 square feet of clear opening. The natural option for a bathroom calls for an aggregate glazing area of not less than 3 square feet, one-half of which must be openable. What is the finding?
  • The outdoor air intake for the ventilation system is a hooded opening in the side wall. The clothes dryer exhaust terminates 4 feet from it and the furnace vent terminal is 6 feet from it, all three at about the same height on the wall. What is the finding?
  • The tub surround is tile that stops 5 feet above the bathroom floor, and from there to the ceiling the wall is painted gypsum board. The builder says the tile height matches the curtain rod. What is the finding?
  • The clear height over the open floor is 7 feet, and a trunk duct crossing the middle of the space leaves 6 feet 2 inches beneath it, measured to the finished floor. The path from the stairs to the laundry passes under that duct. What is the finding?
  • The insulation contractor has adhered 2-inch extruded polystyrene to the exterior face of the concrete foundation wall from the sill plate down to the footing, and the walls framed above are ordinary untreated lumber. What is the finding?

Practice all 44 Building Planning questions

Plus timed mock exams and a wrong book that follows you between the web and the app.

Start studying free

Other ICC B1 content areas