CSLB General Building (B) — All Questions
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700 questions
A weep screed at the base of a stucco wall must be located at least how far above adjacent surfaces?
- a.At least 4 inches above earth or 2 inches above paved areas✓
- b.Flush with the finished grade, meeting the soil directly
- c.At least 8 inches above paved areas in every case
- d.At least 12 inches above earth at every wall base
The foundation weep screed must sit a minimum of 4 inches above earth or 2 inches above paved surfaces so moisture in the stucco can drain out above the splash and grade line. Twelve inches, flush with grade, and 8 inches above paving are not the code-required minimums.2025 CA Residential Code §R703.7.2.1
CALCULATION: Cement plaster control joints are recommended to divide large wall areas into panels not exceeding 144 square feet. On a wall panel 8 feet tall, at about what horizontal spacing should control joints fall to stay within that limit?
- a.12 feet
- b.18 feet✓
- c.24 feet
- d.6 feet
Area = height x length, so length = 144 / 8 = 18 feet. Control joints spaced about 18 feet apart keep each 8-foot-tall panel at roughly 144 square feet. Six or twelve feet would create smaller panels than required, and 24 feet gives 192 square feet, exceeding the 144-square-foot guideline.
When metal lath for three-coat stucco is fastened to a wood-framed wall, how far should the fasteners penetrate the framing?
- a.Just into the sheathing, letting the panel itself hold the lath and the wet plaster wherever a fastener misses a stud
- b.No penetration is needed if the lath is tight, because a drum-tight sheet is held against the wall by its own tension
- c.Into the studs or supports far enough to hold the lath securely (commonly at least about 3/4 to 1 inch)✓
- d.Only into the WRB, so the fastener stops at the barrier and does not carry any moisture deeper into the wall behind it
Lath fasteners must reach into the studs or solid supports enough (commonly on the order of 3/4 to 1 inch) so the lath and the heavy wet plaster cannot pull loose. Fastening only to sheathing, to the WRB, or relying on tight lath without penetration will not hold the plaster.2025 CA Residential Code §R703.7
In traditional three-coat stucco over metal lath, the total nominal thickness is about 7/8 inch. Which sequence of coats builds that thickness?
- a.Scratch coat, brown coat, then finish coat✓
- b.Finish coat, brown coat, then scratch coat
- c.A single thick coat troweled to 7/8 inch
- d.Two brown coats and one scratch coat
Three-coat stucco is applied as a scratch coat (scored to bond the next coat), a brown coat (bringing the wall to plane), and a finish coat, totaling about 7/8 inch over metal lath. Reversing the order, doubling the brown coat, or applying one thick coat are not the standard three-coat method.2025 CA Residential Code §R703.7
Fiber-cement lap siding is installed on a wood-framed wall. What clearance is generally required between the bottom edge of the siding and the finished grade or a roof surface below it?
- a.A clearance (commonly around 6 inches to earth and about 1 to 2 inches above a roof) to keep the siding out of standing water and splash✓
- b.No clearance; siding may touch the ground, because fiber-cement does not rot the way wood siding does when it sits in wet soil at the base of the wall
- c.At least 12 inches above a roof
- d.Siding must be buried 2 inches into the grade so that the bottom course is locked in place and the wind cannot lift the lower edge away from the wall
Manufacturers and the code call for clearance at the bottom of fiber-cement (and most) siding, commonly about 6 inches to earth and roughly 1 to 2 inches above roof surfaces, to keep the siding out of standing water and splash that would wick moisture. No clearance, 12 inches above a roof, or burying the siding are incorrect.2025 CA Residential Code §R703.3
Why is vinyl siding fastened so that the panels can move slightly (nails not driven tight) rather than pinned firmly?
- a.To allow for thermal expansion and contraction so panels do not buckle or crack✓
- b.Because vinyl is structural sheathing, and a slightly loose nail lets the panel carry wall racking without cracking
- c.Because vinyl needs no water-resistive barrier
- d.To make installation faster only
Vinyl expands and contracts significantly with temperature, so nails are left slightly loose and centered in slots to let the panels move; pinning them tight causes buckling in heat and cracking in cold. Speed, structural function, and skipping the WRB are not the reasons for loose fastening.2025 CA Residential Code §R703.11
Where three-coat stucco terminates at a window, door, or dissimilar material, what accessory provides a clean, sealed edge?
- a.A weep screed only, run at the wall base
- b.A drip edge on the roof, set at the eave
- c.A rafter tie across the ceiling framing
- d.A casing bead (plaster stop) at the termination✓
A casing bead, or plaster stop, gives stucco a finished, gauged edge where it terminates against openings or other materials and creates a location to seal against water intrusion. A weep screed is used at the wall base, a rafter tie is a roof member, and a roof drip edge is unrelated to a wall stucco termination.2025 CA Residential Code §R703.7.3
When self-furring metal lath is used for stucco, what does the 'self-furring' feature accomplish?
- a.It replaces the scratch coat, so the plasterer can start with the brown coat directly over the mesh
- b.It eliminates the need for fasteners, since the dimples grip the backing and hold the sheet in place
- c.It holds the lath slightly off the backing so plaster can key fully behind the mesh✓
- d.It makes the lath waterproof, so the mesh keeps water off the backing without any other barrier
Self-furring lath has dimples or ridges that stand it off the backing a small distance, so the first (scratch) coat is pushed through and keys fully behind the mesh for a strong bond. It does not remove the need for fasteners, replace the scratch coat, or make the lath waterproof.2025 CA Residential Code §R703.7.1
A deck ledger is attached to the house rim joist. Which fastening is generally ACCEPTABLE, and which is NOT?
- a.Any construction adhesive alone is acceptable, since a full glue line spreads the load over the whole face of the ledger
- b.Through-bolts or approved lag screws in a prescribed pattern are acceptable; nails alone are not✓
- c.Standard drywall screws are acceptable, because enough of them in a close pattern will add up to the same capacity
- d.Toenails driven at an angle are acceptable
A deck ledger must be fastened with through-bolts or approved lag screws laid out per the code table, because they resist the tension pulling the deck away from the house; nails, drywall screws, toenails, or adhesive alone cannot safely carry those loads and are prohibited for ledger attachment.2025 CA Residential Code §R507.9.1.3
What flashing detail BEST protects the house at a deck ledger connection?
- a.Painting the ledger black, so the coating seals the wood and the dark surface dries out any water that reaches it before rot can start
- b.No flashing, just caulk the top
- c.A strip of untreated cardboard
- d.Corrosion-resistant flashing that directs water out over the ledger and integrates with the wall's water-resistive barrier✓
Proper ledger flashing is a corrosion-resistant metal or approved flashing lapped so water sheds out and away over the top of the ledger and integrates with the WRB, preventing rot behind the ledger. Caulk alone, cardboard, or paint do not create a durable, integrated drainage detail.2025 CA Residential Code §R507.9.1.4
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For a wood deck post that carries deck loads down to a footing, which connection detail is MOST important at the base?
- a.A decorative cap is all that is required to finish the base of the post
- b.The post may simply rest on soil, with the deck's weight holding it in place
- c.The post should be buried in the ground without treatment so the soil braces it
- d.A post base/anchor that ties the post to the footing and resists uplift and lateral movement✓
A code-compliant deck post uses a metal post base or anchor connecting it to the concrete footing so the post cannot slide off or lift, transferring gravity, uplift, and lateral loads. Resting on soil, burying untreated wood, or relying on a decorative cap does not provide the required structural connection.2025 CA Residential Code §R507.4
CALCULATION: A deck uses 2x8 pressure-treated joists of a species with a span table value of 12 feet at 16 inches on center. If the framer moves the joists to 12 inches on center, the allowable span will generally:
- a.Stay exactly the same, because the table value belongs to the joist size and species, not to the spacing
- b.Decrease to zero, because joists set that close are treated as one built-up member with no rated span
- c.Double to 24 feet, since each joist now carries half the floor area that it carried before
- d.Increase somewhat, because closer joists each carry less load✓
Spacing joists closer together (16 to 12 inches on center) gives each joist a smaller tributary load, so span tables allow a somewhat longer span at the tighter spacing. It does not drop to zero, stay identical, or double; the increase is modest, per the table, not a doubling.2025 CA Residential Code §R507.6
Where a deck beam bears on a supporting post, what is the BEST practice for the connection?
- a.Set the beam beside the post and rely on nails to hold it up, so that the post can run past the beam and continue upward to the guard above the deck
- b.Seat the beam so it bears on top of the post (or in an approved saddle/cap) with a positive connection to resist uplift and displacement✓
- c.Use adhesive only
- d.Balance the beam on top of a single nail, using the nail as a pin that lets the beam settle down evenly onto the post as the deck is loaded from above
Best practice seats the deck beam directly on top of the post or in an approved post cap/saddle so gravity load bears in compression, with a mechanical connection (bolts or an approved cap) resisting uplift and sideways movement. Side-nailing the beam, balancing on a nail, or adhesive alone are unsafe connections.2025 CA Residential Code §R507.5
Besides the ledger fasteners, the code requires a lateral load connection between the deck and the house structure. What does this connection primarily prevent?
- a.The deck pulling away from the house under lateral load✓
- b.Insect damage
- c.Rain from reaching the ledger, by pulling the deck framing tight against the house wall
- d.Squeaky deck boards
The lateral load connection (typically hold-down tension devices anchored into the house floor framing) resists the horizontal force that would pull a deck away from the house, a common cause of catastrophic deck collapses. It is not about squeaks, rain, or insects, which other details address.2025 CA Residential Code §R507.9.2
On a raised residential deck, guards are required, and the guard infill (balusters/pattern) must be designed so that which object cannot pass through?
- a.A 6-inch sphere
- b.A 4-inch sphere✓
- c.A basketball
- d.A 5-inch sphere
Deck and balcony guard openings must be small enough that a 4-inch-diameter sphere cannot pass through the infill, protecting small children. A 6-inch or 5-inch sphere limit is too loose for guard infill (6 inches applies only to the triangle at open stairs), and 'a basketball' is not a code criterion.2025 CA Residential Code §R321.1.3
Why must deck framing lumber in contact with the weather and near the ground be pressure-preservative-treated or naturally durable?
- a.To make it lighter so the framing is easier to carry and handle
- b.To resist decay and insect attack in the exposed, moist environment✓
- c.To make painting unnecessary over the life of the deck
- d.To improve its color and give the boards a uniform look
Exterior deck lumber sits in a wet, exposed environment where untreated wood rots and is attacked by insects, so it must be preservative-treated or a naturally durable species to last. Treatment is not about reducing weight, improving color, or eliminating the option to paint or finish.2025 CA Residential Code §R507.2
CALCULATION: A stairway must rise a total of 112 inches from finished floor to finished floor. Using the 7-3/4 inch maximum riser height, what is the MINIMUM number of risers required?
- a.16 risers
- b.15 risers✓
- c.14 risers
- d.13 risers
Divide total rise by the maximum riser: 112 / 7.75 = 14.45, which must round UP to 15 risers so each riser stays at or below 7-3/4 inch (112 / 15 = 7.47 inch). Thirteen or fourteen risers would exceed the maximum height, and 16 is more than the minimum needed.2025 CA Residential Code §R318.7.5.1
CALCULATION: A stair has 15 risers. Using a 10-inch tread depth, what is the total horizontal run of the flight (number of treads times tread depth)?
- a.150 inches
- b.160 inches
- c.140 inches✓
- d.110 inches
A straight flight has one fewer tread than risers: 15 - 1 = 14 treads. Total run = 14 x 10 inch = 140 inches. Using 15 treads (150 inches) forgets that the top riser lands on the floor, 110 and 160 inches use the wrong tread count.2025 CA Residential Code §R318.7.5.2
CALCULATION: A roof area of 200 square feet is subject to a net wind uplift pressure of 15 pounds per square foot. What total uplift force must the connections in that area resist?
- a.13 pounds
- b.1,500 pounds
- c.215 pounds
- d.3,000 pounds✓
Total force = pressure x area = 15 psf x 200 sq ft = 3,000 pounds. The connections (straps, ties, anchors) in that area must resist that 3,000-pound uplift. 1,500 pounds halves the area or pressure, 215 pounds adds instead of multiplies, and 13 pounds divides incorrectly.
At the top and bottom of a residential stairway, a floor or landing is required. What is the MINIMUM dimension of that landing measured in the direction of travel?
- a.24 inches
- b.30 inches
- c.48 inches
- d.36 inches✓
A stairway landing must be at least 36 inches measured in the direction of travel, giving a safe place to pause and change direction. Twenty-four and thirty inches are too small, and 48 inches is more than the code minimum (though it may be provided).2025 CA Residential Code §R318.7.6
For a circular (Type I) handrail, what is the required graspable cross-section?
- a.Exactly 1 inch in diameter, a slim rail that the fingers can close all the way around
- b.At least 3 inches in diameter, so there is plenty of rail for a large hand to hold on to
- c.An outside diameter of at least 1-1/4 inch and not more than 2 inches✓
- d.Any size, as long as it is smooth and free of splinters that could catch a sliding hand
A circular handrail must have an outside diameter between 1-1/4 inch and 2 inches so a hand can close around it securely. 'Any size,' a 3-inch diameter (too large to grasp), and a fixed 1-inch (below the minimum) do not meet the graspability requirement.2025 CA Residential Code §R320.6
A required stair handrail must be continuous along the flight. How should the ends of the handrail be treated?
- a.Left open with sharp ends, so the rail can be cut to length on site without any extra fittings or returns
- b.Returned to the wall or terminated in a newel/safety terminal so clothing cannot catch✓
- c.Cut off flush at the top step only, since a hand leaving the flight no longer needs anything to hold
- d.Removed at the landing
Handrail ends must return to the wall or end in a newel post or safety terminal so that loose clothing, bags, or hands cannot catch on an open end. Leaving sharp open ends, cutting off only at the top, or removing the rail at the landing all create hazards and break continuity.2025 CA Residential Code §R320.5
On a stair with solid risers and treads less than 11 inches deep, a nosing is required. What projection range does the code specify for that nosing?
- a.0 to 1/4 inch
- b.3/4 inch to 1-1/4 inch✓
- c.2 to 3 inches
- d.1 to 2 inches
Where a nosing is required, it must project between 3/4 inch and 1-1/4 inch beyond the riser below, giving extra effective foot depth without becoming a trip hazard. The other ranges are either too small to help or so large they create a catch point and are not code-compliant.2025 CA Residential Code §R318.7.5.3
CALCULATION: Two stair carriages (stringers) are each cut from a 2x12 that is 14 feet long. Using nominal dimensions, how many total board feet of lumber is that?
- a.56 board feet✓
- b.42 board feet
- c.21 board feet
- d.28 board feet
Board feet per piece = (nominal thickness in inches x nominal width in inches x length in feet) / 12 = (2 x 12 x 14) / 12 = 28 board feet each. Two stringers = 2 x 28 = 56 board feet. 28 counts only one piece, 42 and 21 use the wrong figures.
A spiral stairway is permitted in a dwelling under special rules. Which requirement is characteristic of a code-compliant spiral stair?
- a.Each tread provides a minimum run at a defined walk-line point (about 12 inches from the narrow edge) and headroom is at least 6 feet 6 inches✓
- b.No center column is allowed
- c.Treads must be at least 11 inches deep at every point, including at the narrow inside edge by the column, so the stair walks the same as a straight flight
- d.Risers may be any height with no limit
Spiral stairs are allowed with special geometry: the tread depth is measured at a walk line roughly 12 inches from the narrower edge and must meet a minimum there, with reduced but defined headroom of at least 6 feet 6 inches. Uniform 11-inch treads, unlimited risers, and a no-center-column rule do not describe a spiral stair.2025 CA Residential Code §R318.7.11.1
For a conventionally framed one-story dwelling using 2x4 studs, what is the MAXIMUM on-center spacing generally permitted for load-bearing wall studs supporting a roof and ceiling only?
- a.24 inches✓
- b.32 inches
- c.12 inches
- d.48 inches
The residential code stud tables allow 2x4 bearing studs supporting roof and ceiling to be spaced up to 24 inches on center. 12 inches is more conservative than required and wastes material; 32 and 48 inches exceed the tabulated maximum for 2x4 bearing studs and would over-stress the wall.2025 CA Residential Code §R602.3.1
When installing tongue-and-groove wood structural panel subflooring, which practice BEST reduces squeaks and improves diaphragm performance?
- a.Butting panel edges tightly with no gap
- b.Nailing only at panel corners
- c.Laying all end joints on a single joist in a continuous line
- d.Gluing the panels to the joists in addition to fastening✓
Field-gluing the subfloor to the joists with construction adhesive in addition to nailing or screwing greatly reduces squeaks and stiffens the diaphragm. Panel edges need a small expansion gap, not a tight butt; fastening only at corners leaves the field unsupported; and aligning all end joints on one line creates a weak, hinge-like seam rather than a staggered layout.2025 CA Residential Code §R503
A gable roof has a total run of 12 feet (horizontal from wall to ridge) and a slope of 6:12. Ignoring ridge and overhang, what is the approximate line length of a common rafter along the slope?
- a.About 6 feet 0 inches
- b.About 12 feet 0 inches
- c.About 15 feet 0 inches
- d.About 13 feet 5 inches✓
Rafter line length equals run times the unit-length factor. For a 6:12 slope the diagonal per 12 units of run is the square root of (12² + 6²) = 13.416 units, a factor of about 1.118. Multiply 12 ft run by 1.118 to get roughly 13.42 ft, or about 13 ft 5 in. 12 ft ignores the slope; 15 ft overshoots; 6 ft is the rise, not the rafter length.2025 CA Residential Code §R802
Under the residential code, what is the MAXIMUM permitted riser height for a stairway serving a dwelling?
- a.7 3/4 inches✓
- b.6 inches
- c.7 1/2 inches
- d.7 inches
The residential code caps riser height at 7 3/4 inches for stairs within dwellings. 6 and 7 inches are allowable but not the maximum; 7 1/2 inches is close but still below the code ceiling. Note the commercial building code uses a lower 7-inch maximum, so the value depends on occupancy.2025 CA Residential Code §R318.7.5
For a dwelling stairway, what is the MINIMUM tread depth (run) required, measured horizontally between the leading edges of adjacent treads?
- a.12 inches
- b.9 inches
- c.10 inches✓
- d.11 inches
The residential code requires a minimum tread depth of 10 inches for dwelling stairs. 9 inches is below the minimum and would be too steep; 11 and 12 inches exceed the minimum and are acceptable but not the required floor value. The commercial code requires a deeper 11-inch tread.2025 CA Residential Code §R318.7.5
Under the California Residential Code, guards on the open sides of walking surfaces in a dwelling must be at least what height above the adjacent walking surface?
- a.36 inches
- b.34 inches
- c.42 inches✓
- d.30 inches
CRC R321.1.2 requires guards not less than 42 inches above the adjacent walking surface. 36 inches is the model IRC figure, which California amends. 34 inches is the minimum only for guards on the open sides of stairs, measured from the line of the nosings. 30 inches is the drop height that triggers a guard, not the guard height.2025 CA Residential Code §R321.1.2
A required stair handrail must be mounted so its top is within what vertical range above the tread nosings?
- a.34 to 38 inches✓
- b.36 to 42 inches
- c.30 to 34 inches
- d.42 to 48 inches
Handrail top height must be between 34 and 38 inches measured vertically from the nosing line. 30 to 34 inches is too low; 36 to 42 and 42 to 48 inches are too high and overlap guard heights rather than handrail heights.2025 CA Residential Code §R318.7.8, §R320.2
For a conventionally framed wall anchored to a concrete foundation, anchor bolts of at least 1/2-inch diameter must generally be spaced no more than what distance on center?
- a.8 feet
- b.6 feet✓
- c.10 feet
- d.4 feet
The residential code generally requires 1/2-inch anchor bolts at a maximum of 6 feet on center, with a bolt located within 12 inches of each plate end. 4 feet is more conservative than required; 8 and 10 feet exceed the maximum spacing and would under-anchor the sill plate against uplift and sliding.2025 CA Residential Code §R403.1.6
In a wood-framed shear wall resisting seismic loads, what is the PRIMARY function of a hold-down device installed at the wall ends?
- a.To level the top plate during framing before sheathing goes on
- b.To act as a vapor barrier at the wall base above the foundation
- c.To provide a nailing surface for siding at the wall ends
- d.To resist overturning uplift and anchor the end post to the foundation✓
A hold-down ties the shear wall's end post (chord) to the foundation to resist the uplift produced when lateral forces try to overturn the wall. It does not level plates, provide siding nailing, or act as a vapor barrier; those are unrelated framing or moisture functions.2025 CA Residential Code §R602.10
When applying three-coat Portland cement plaster (stucco) over wood framing on an exterior wall, a weep screed must be installed at the foundation plate line at least how far above the earth?
- a.4 inches above earth (or 2 inches above paved surfaces)✓
- b.3 inches above earth
- c.1 inch above earth
- d.2 inches above earth
A corrosion-resistant weep screed must be placed a minimum of 4 inches above earth or 2 inches above paved areas to let moisture drain out of the wall assembly. 1, 2, and 3 inches above earth are insufficient clearance and could wick soil moisture into the plaster and framing.2025 CA Residential Code §R703.7.2.1
Traditional three-coat stucco applied over metal lath on a framed wall should have what approximate MINIMUM total nominal thickness measured from the face of the lath?
- a.1 1/2 inches
- b.7/8 inch✓
- c.3/8 inch
- d.1/4 inch
Three-coat stucco (scratch, brown, and finish coats) is built to a nominal total thickness of about 7/8 inch measured from the face of the lath. 3/8 and 1/4 inch are far too thin for a three-coat system, and 1 1/2 inches is thicker than standard and unnecessary.2025 CA Residential Code §R703.7
To resist lateral separation of an exterior wood deck from the dwelling during seismic or live loads, which connection is the BEST practice at the ledger-to-band-joist interface?
- a.Install tension hold-down devices connecting the deck framing to the interior floor framing✓
- b.Toenail the joists into the ledger at each bay
- c.Rely solely on the deck ledger lag screws for lateral resistance, since they already pass through the band joist
- d.Use construction adhesive between the ledger and the house wall to bond the two surfaces into one continuous joint
Code-recognized lateral load connectors (tension devices) tie the deck joists through the wall to the interior floor framing, directly resisting the deck pulling away. Ledger lag screws primarily carry vertical shear, not lateral tension; adhesive is not a rated structural connection; and toenailing alone is far too weak for lateral loads.2025 CA Residential Code §R507
How many board feet are contained in ten framing members that are each 2 inches thick, 6 inches wide, and 12 feet long?
- a.100 board feet
- b.120 board feet✓
- c.144 board feet
- d.60 board feet
Board feet per piece equals (thickness in inches x width in inches x length in feet) divided by 12: (2 x 6 x 12) / 12 = 12 board feet each. Ten pieces total 120 board feet. 60 is the count for five pieces; 100 and 144 do not match the calculation.
In high-wind and seismic regions, what is the MAIN purpose of installing metal framing anchors (hurricane or seismic ties) connecting each rafter or truss to the top plate?
- a.To provide a ground path for lightning
- b.To speed alignment of the ridge board
- c.To resist uplift and lateral forces that could separate the roof from the walls✓
- d.To replace the need for roof sheathing nails, since the metal anchors already hold the panels to the framing
Rafter or truss ties create a continuous load path that resists wind uplift and seismic forces trying to pull the roof off the walls. They do not align the ridge, ground lightning, or substitute for sheathing fasteners, all of which serve different structural or safety roles.2025 CA Residential Code §R802.11
When prefabricated wood roof trusses are delivered to a jobsite, which practice BEST preserves their engineered performance?
- a.Store them flat-stacked in mud until installation day on site
- b.Install them only per the truss manufacturer's engineered layout and bracing plan✓
- c.Field-cut chords or webs as needed to fit around obstructions in the way
- d.Notch the bottom chord to run plumbing lines without approval from anyone
Trusses are engineered assemblies that must be installed and braced exactly per the manufacturer's layout and bracing design. Field-cutting chords or webs, notching the bottom chord, or storing them improperly all compromise the engineered load path and can void the design and cause failure.2025 CA Residential Code §R802.3
What is the MINIMUM headroom clearance required over a residential stairway, measured vertically from the tread nosing line?
- a.6 feet 4 inches
- b.7 feet 6 inches
- c.7 feet 0 inches
- d.6 feet 8 inches✓
The residential code requires a minimum 6 feet 8 inches of headroom above the stair, measured vertically from a line connecting the tread nosings. 6 feet 4 inches is below the minimum; 7 feet 0 inches and 7 feet 6 inches exceed the requirement and are not the code floor value.2025 CA Residential Code §R318.7.2
What is the MINIMUM clear width required above the handrail for an interior residential stairway?
- a.44 inches
- b.30 inches
- c.36 inches✓
- d.32 inches
Residential stairs must provide a minimum clear width of 36 inches above the permitted handrail height. 30 and 32 inches are narrower than allowed; 44 inches is a common commercial minimum and exceeds the residential requirement.2025 CA Residential Code §R318.7.1
Guards required on decks and balconies must have intermediate rails or ornamental patterns such that a sphere of what MAXIMUM diameter cannot pass through the openings?
- a.6 inches
- b.5 inches
- c.4 inches✓
- d.4 3/8 inches
Guard openings must not allow passage of a 4-inch-diameter sphere, limiting the gap so small children cannot slip through. 6, 5, and 4 3/8 inches all exceed the 4-inch limit and would leave unsafe openings.2025 CA Residential Code §R321.1.3
In conventional platform framing, what is the PRIMARY structural role of the double top plate on a bearing wall?
- a.To act as a fire sprinkler mounting rail, giving the piping a continuous line to hang from at the top of the wall
- b.To serve as a nailing base for baseboard trim and other finish carpentry fastened to the wall framing
- c.To tie wall segments together and distribute loads from rafters or joists above✓
- d.To provide the finished ceiling line, setting the height at which the drywall and its trim stop
The double top plate laps at corners and intersections to tie wall segments into a continuous unit and distribute point and uniform loads from framing above. It is not for baseboard nailing, ceiling finish, or sprinkler mounting, which are unrelated to its load-transfer purpose.2025 CA Residential Code §R602.3
When installing horizontal lap siding, which practice BEST manages moisture behind the cladding?
- a.Apply siding directly to studs without sheathing or barrier, letting the boards themselves act as the weather surface
- b.Nail the siding tight with no gap so no water can enter
- c.Seal all vertical joints airtight with no flashing, so that water is stopped at the face before it can get behind
- d.Install a water-resistive barrier and lap the siding to shed water over the course below✓
Lap siding works with a water-resistive barrier and proper lapping so any water is directed outward and downward over the course below. Sealing joints airtight traps moisture, nailing tight ignores the drainage principle, and omitting sheathing and a barrier leaves the wall unprotected.2025 CA Residential Code §R703.3
A stair must rise a total of 108 inches from finished floor to finished floor. If each riser is designed at 7.2 inches, how many risers are required?
- a.14 risers
- b.15 risers✓
- c.18 risers
- d.12 risers
Number of risers equals total rise divided by riser height: 108 / 7.2 = 15 risers exactly. 12 risers would give a 9-inch riser (too tall); 14 risers gives about 7.7 inches (acceptable but not the designed 7.2); 18 risers gives only 6 inches, more than designed.
When a plumbing or mechanical run requires boring holes in load-bearing wall studs, the code limits bored hole diameter to no more than what fraction of the stud depth, unless the stud is doubled?
- a.60 percent
- b.70 percent
- c.50 percent
- d.40 percent✓
R602.6 allows bored holes up to 40 percent of the stud depth in exterior and bearing walls without further steps. Over 40 percent, the stud must be doubled, and no more than two successive doubled studs may be bored that way. 60 percent is the overall limit even then, 50 percent would still require doubling, and 70 percent is never allowed by this rule.2025 CA Residential Code §R602.6
For exterior wood decks, which material designation BEST indicates lumber suitable for the wet, ground-contact exposure of deck posts set near grade?
- a.Finger-jointed trim stock
- b.Preservative-treated lumber rated for ground contact✓
- c.Untreated standard framing lumber, since a heavy post section dries out faster than it can decay
- d.Kiln-dried interior-grade lumber
Deck posts near grade require preservative-treated lumber rated for ground contact to resist decay and insects. Kiln-dried interior lumber, untreated framing lumber, and finger-jointed trim are all unsuited to sustained moisture and will deteriorate.2025 CA Residential Code §R507.2
In a braced wall line using wood structural panel sheathing, which nailing change MOST directly increases the shear capacity of the wall?
- a.Decreasing panel edge nail spacing from 6 to 4 inches✓
- b.Using a smaller-diameter nail at the same spacing
- c.Removing nails at the panel field
- d.Increasing panel edge nail spacing from 4 to 6 inches
Tighter edge nailing, such as reducing spacing from 6 to 4 inches on center, transfers more shear per foot and increases the wall's capacity. Widening the spacing, removing field nails, or using thinner nails all reduce capacity rather than increase it.2025 CA Residential Code §R602.10.4
A common rafter has a horizontal run of 10 feet and a rise of 5 feet. What is the roof slope expressed as unit rise per 12 units of run?
- a.6:12✓
- b.12:12
- c.4:12
- d.3:12
Slope in rise-per-12 equals (rise / run) x 12 = (5 / 10) x 12 = 6, so the slope is 6:12. 3:12 and 4:12 are shallower than the actual ratio, and 12:12 would require the rise to equal the run.