CSLB General Building (B) — All Questions

On a roof slope of 4:12 or greater covered with asphalt shingles, the underlayment must consist of at least:

• a.One layer, applied with specified horizontal and end laps✓
• b.Two full layers regardless of slope, doubling the protection on every roof
• c.A layer of rigid insulation board
• d.No underlayment when self-sealing shingles are used, since the shingles seal to one another

For slopes of 4:12 and steeper, a single layer of underlayment lapped a set amount at horizontal and end joints is required, because water sheds quickly. Slopes below 4:12 (down to the 2:12 minimum) require a doubled underlayment. Underlayment is never omitted, and rigid insulation is not underlayment.2025 CA Residential Code §R905.1.1

The MINIMUM roof slope on which asphalt shingles may be installed (with a doubled underlayment) is:

• a.2:12✓
• b.1:12
• c.4:12
• d.3:12

Asphalt shingles may be applied on slopes as low as 2:12, but only with a doubled underlayment because water drains slowly and can back up. A 1:12 slope is too flat for shingles and requires a low-slope membrane roof. 3:12 and 4:12 are valid but are not the minimum.2025 CA Residential Code §R905.2.2

A simple gable roof has two identical planes, each measuring 40 ft along the ridge by 18 ft up the slope. How many roofing squares of material cover the roof (before waste)?

• a.14.4 squares✓
• b.12 squares
• c.18 squares
• d.21.6 squares

Each plane is 40 x 18 = 720 square feet; two planes total 1,440 square feet. One roofing square equals 100 square feet, so 1,440 / 100 = 14.4 squares. 12 and 21.6 come from counting one plane or mis-multiplying; the calculation must use the sloped dimension, not the flat footprint.

In an open valley on a shingle roof, metal valley flashing is installed primarily to:

• a.Ventilate the attic space
• b.Serve as decorative trim
• c.Hold the shingles down against wind uplift where the two planes meet and wind pressure is highest
• d.Channel concentrated water runoff and prevent leaks where two roof planes meet✓

A valley collects runoff from two intersecting planes, so metal valley flashing forms a durable, watertight channel to carry that concentrated flow off the roof. It is not primarily a fastener, a vent, or decoration; those roles are served by other components.2025 CA Residential Code §R905.2.8

A drip edge at the eaves and rakes of a shingle roof functions primarily to:

• a.Hold the underlayment in place during high wind before the shingles go on
• b.Direct water away from the fascia and into the gutter, protecting the roof edge✓
• c.Provide attic ventilation at the edge for air entering the soffit
• d.Increase the slope of the roof so that runoff leaves the surface faster

A drip edge is metal flashing at the roof edge that guides runoff off the sheathing and fascia and into the gutter, preventing water from wicking behind the edge and rotting the wood. It does not change slope, is not primarily a fastener for underlayment, and does not ventilate the attic.2025 CA Residential Code §R905.2.8.5

A roof has a total surface area of 2,000 square feet. Adding a 15% allowance for waste, hips, and starter courses, how many roofing squares should be ordered?

• a.23 squares✓
• b.25 squares
• c.20 squares
• d.21.5 squares

2,000 square feet equals 2,000 / 100 = 20 squares of net area. Adding 15% for waste: 20 x 1.15 = 23 squares. 20 squares ignores waste; 21.5 uses about 7.5% instead of 15%; 25 overstates the allowance.

The R-value of an insulation material is a measure of its:

• a.Density, meaning how much mass the material packs into a given volume
• b.Resistance to heat flow (thermal resistance)✓
• c.Fire-resistance rating, meaning how long the material withstands fire
• d.Vapor permeability, meaning how readily water vapor passes through it

R-value quantifies thermal resistance; a higher R-value means the material slows conductive heat flow more effectively. It is the inverse of the U-factor. R-value does not directly indicate fire rating, density, or how readily vapor passes through the material.

In a heating-dominated (cold-winter) climate, a vapor retarder in an exterior wall is generally installed on which side of the insulation?

• a.The exterior (cold) side, just inside the sheathing
• b.The interior (warm-in-winter) side✓
• c.It is omitted entirely
• d.Both faces of the insulation, sealing it in from either side

In a cold climate the warm, moist interior air moves outward, so the vapor retarder goes on the interior (warm) side to stop moisture before it reaches the cold sheathing where it would condense. Placing it on the cold side, or on both sides, can trap moisture inside the wall and cause rot.2025 CA Residential Code §R702.7

Under current California Energy Code prescriptive requirements, wood-framed ceiling/attic insulation in most climate zones must reach a MINIMUM of about:

• a.R-30, applied uniformly in every climate zone
• b.R-13
• c.R-38 or higher✓
• d.R-19

Prescriptive ceiling insulation in most California climate zones is R-38 or greater, because the roof/attic is a major heat-loss and heat-gain surface. R-13 and R-19 are typical wall values, and R-30 is below the prescriptive ceiling requirement for most zones.2025 CA Energy Code §150.1

A wall uses R-15 cavity batt insulation plus R-6 continuous exterior rigid insulation. Ignoring framing and air films, what is the combined nominal thermal resistance of these two insulation layers?

• a.R-90
• b.R-15
• c.R-9
• d.R-21✓

Thermal resistances of layers in series add together, so R-15 + R-6 = R-21. R-9 subtracts the values, R-15 ignores the continuous insulation, and R-90 incorrectly multiplies them. Series R-values are always summed.

A continuous water-resistive barrier (building paper or house wrap) installed behind exterior cladding functions primarily to:

• a.Provide a drainage plane that sheds incidental water and protects the sheathing✓
• b.Add thermal insulation value to the wall behind the cladding
• c.Add structural shear strength to the wall in place of bracing
• d.Block sound transmission through the wall from outdoor noise sources

The water-resistive barrier creates a continuous drainage plane so any water that gets past the cladding runs down and out rather than soaking the sheathing and framing. It provides negligible insulation, no structural strength, and little sound control; those come from other assemblies.2025 CA Residential Code §R703.2

Structural fill placed under a building slab is typically required to be compacted to a MINIMUM relative compaction of about:

• a.70%
• b.100%
• c.90%✓
• d.80%

Engineered structural fill is generally compacted to at least 90% relative compaction (based on a laboratory maximum dry density) to limit settlement under the slab; critical areas may require 95%. 70% and 80% are too loose and would allow settling, while a sustained 100% is impractical to achieve uniformly.2025 CA Building Code, Chapter 18 (Soils and Foundations)

An excavation for a basement measures 30 ft long, 20 ft wide, and 3 ft deep. How many bank cubic yards of soil are removed?

• a.55.6 cubic yards
• b.66.7 cubic yards✓
• c.88.9 cubic yards
• d.72 cubic yards

Volume = 30 x 20 x 3 = 1,800 cubic feet. Divide by 27 to convert to cubic yards: 1,800 / 27 = 66.7 bank cubic yards. 72 comes from dividing by 25, and the other values from arithmetic errors. This is the in-place (bank) volume before any swell.

In construction surveying, a 'benchmark' is BEST described as:

• a.The centerline of an access road, from which the other features on the site are laid out and staked
• b.A fixed reference point of known elevation used to establish grades and levels✓
• c.The highest point along a graded slope, taken as the reference from which cuts are measured
• d.The property corner between two lots, established by the recorded survey of the subdivision

A benchmark is a permanent, fixed point whose exact elevation is known; surveyors reference it to set finished grades and building elevations. A property corner is a horizontal boundary marker, not an elevation reference, and neither a slope high point nor a road centerline serves as the datum for elevations.

A contractor must haul away 100 bank cubic yards (in-place volume) of soil that has a swell factor of 25%. What loose volume must the trucks carry?

• a.100 loose cubic yards
• b.75 loose cubic yards
• c.112 loose cubic yards
• d.125 loose cubic yards✓

Excavating loosens soil so it occupies more space; a 25% swell means the loose volume is the bank volume times 1.25: 100 x 1.25 = 125 loose cubic yards. 100 ignores swell, 75 wrongly reduces the volume, and 112 uses about 12% instead of 25%.

Holding cement content and curing constant, which change to a concrete mix will generally produce the HIGHEST compressive strength?

• a.Using rounded aggregate instead of angular aggregate
• b.Lowering the water-to-cement ratio✓
• c.Adding more mixing water for easier placement
• d.Increasing the slump

Compressive strength is governed mainly by the water-to-cement ratio; lowering it produces a denser, stronger paste. Adding water or increasing slump raises the water-to-cement ratio and weakens the concrete. Aggregate shape affects workability but is not the primary strength driver.2025 CA Building Code, Chapter 19 (Concrete) per ACI 318

Air-entraining admixtures are added to concrete PRIMARILY to improve resistance to:

• a.Chemical attack from sulfates in soil that reach the concrete through groundwater
• b.Abrasion from vehicle traffic that wears away the finished surface
• c.Cracking caused by drying shrinkage
• d.Damage from repeated freezing and thawing✓

Entrained air creates microscopic bubbles that give freezing water room to expand, which is why air entrainment mainly protects against freeze-thaw damage. Sulfate resistance comes from cement type, shrinkage cracking from mix and curing control, and abrasion resistance from strength and finishing, not from entrained air.2025 CA Building Code, Chapter 19 (Concrete)

A driveway slab measures 24 ft by 30 ft and is 4 inches thick. Approximately how many cubic yards of concrete are required (no waste allowance)?

• a.8.9 cubic yards✓
• b.6.7 cubic yards
• c.26.7 cubic yards
• d.11.9 cubic yards

Volume = 24 x 30 x (4/12) = 240 cubic feet; 240 / 27 = about 8.9 cubic yards. The 6.7 figure omits part of the area, 11.9 assumes a thicker slab, and 26.7 mistakenly leaves the thickness in feet as a whole number instead of converting 4 inches to 0.33 ft.

For typical residential foundations in a moderate weathering region, what is a common MINIMUM specified 28-day compressive strength for the concrete?

• a.1,500 psi
• b.8,000 psi
• c.5,000 psi
• d.2,500 psi✓

Residential foundation concrete is commonly specified at a minimum of 2,500 psi in moderate weathering areas. 1,500 psi is too low for structural foundation use, while 5,000 and 8,000 psi are high-strength mixes used for heavily loaded columns or specialty work, not standard house footings.2025 CA Residential Code, R402.2 (Concrete)

A continuous foundation footing is 18 inches wide, 10 inches deep, and 90 feet long. Approximately how many cubic yards of concrete does it contain?

• a.4.2 cubic yards✓
• b.3.5 cubic yards
• c.12.5 cubic yards
• d.2.8 cubic yards

Convert to feet: 1.5 ft x 0.833 ft x 90 ft = 112.5 cubic feet; 112.5 / 27 = about 4.2 cubic yards. The lower figures understate the cross-section, and 12.5 results from leaving dimensions in inches or failing to divide by 27.

When placing concrete in cold weather, the MOST important protective measure is to:

• a.Add extra water to keep the mix workable in the cold
• b.Remove all curing blankets as soon as finishing is complete so the surface can be inspected
• c.Increase the slump to speed up placement
• d.Keep the concrete above freezing until it has gained adequate early strength✓

Fresh concrete must be kept above freezing until it develops enough early strength, because water freezing in the paste disrupts hydration and permanently weakens it. Adding water or increasing slump raises the water-to-cement ratio and lowers strength, and removing insulation early exposes the concrete to freezing.2025 CA Building Code, Chapter 19 (Concrete)

Tooled or sawn control (contraction) joints are placed in a concrete slab-on-grade PRIMARILY to:

• a.Control where shrinkage cracking occurs by creating planned weak planes✓
• b.Increase the load-carrying capacity of the slab under traffic
• c.Provide a decorative surface pattern across the finished slab
• d.Allow the slab to expand upward during hot weather without lifting

Control joints create planned weakened planes so drying-shrinkage cracks form neatly along the joint rather than randomly across the slab. They do not add structural capacity, are not primarily decorative, and are for shrinkage control rather than upward expansion.2025 CA Building Code, Chapter 19 (Concrete)

A concrete foundation wall is 8 ft tall, 40 ft long, and 8 inches thick. Approximately how many cubic yards of concrete are needed (no waste allowance)?

• a.6.3 cubic yards
• b.9.5 cubic yards
• c.4.7 cubic yards
• d.7.9 cubic yards✓

Volume = 8 x 40 x (8/12) = 213.3 cubic feet; 213.3 / 27 = about 7.9 cubic yards. The lower answers understate wall thickness or length, and 9.5 overstates the thickness.

Rebar chairs and bar supports are used during concrete placement PRIMARILY to:

• a.Reduce the amount of concrete needed by taking up space inside the form that would otherwise be filled
• b.Speed up the concrete pour by giving the crew something to stand on while they place and move the mix
• c.Hold reinforcing steel at the correct height so the required concrete cover is maintained✓
• d.Act as expansion joints in the slab, dividing the pour so that movement is taken up along those lines

Bar supports (chairs) hold the reinforcement at the specified position so that the required concrete cover is achieved and the steel is protected from corrosion. They do not speed the pour, reduce concrete quantity, or function as expansion joints.2025 CA Building Code, Chapter 19 (Concrete)

When selecting the maximum size of coarse aggregate for reinforced concrete, a common limit is that the aggregate should NOT exceed:

• a.Three-fourths of the minimum clear spacing between reinforcing bars✓
• b.Twice the diameter of the largest reinforcing bar used anywhere in the member being placed
• c.The thickness of the concrete cover multiplied by four, measured to the nearest bar
• d.The full depth of the slab

A standard rule limits maximum aggregate size to three-fourths of the minimum clear spacing between bars (and related limits for cover and member size) so concrete can flow around the steel without honeycombing. Sizing the aggregate from twice the diameter of the largest bar ignores how close the bars actually are to each other; tying it to the concrete cover multiplied by four sets a limit far wider than the gaps the mix must pass through; and the full depth of the slab is a member dimension, not a spacing, so stone that size could never be consolidated around the reinforcement.2025 CA Building Code, Chapter 19 (Concrete) per ACI 318

A water-reducing admixture is added to a concrete mix PRIMARILY to:

• a.Replace the need for reinforcing steel
• b.Increase the water-to-cement ratio for easier finishing, so the crew can work the surface longer
• c.Achieve the desired workability while using less water, preserving strength✓
• d.Extend the curing time to 28 days

Water reducers let a mix reach the needed slump with less water, keeping the water-to-cement ratio low so strength is preserved. They lower, not raise, the water-to-cement ratio, do not set the curing period, and never substitute for structural reinforcement.2025 CA Building Code, Chapter 19 (Concrete)

In a dwelling, GFCI protection is generally required for 125-volt receptacles installed in which of the following locations?

• a.Bathrooms, kitchens serving countertops, garages, and outdoor locations✓
• b.Only in unfinished basements, where the floor is bare concrete
• c.Only in bedrooms, on the outlets serving the sleeping area
• d.Only where a swimming pool is present on the same property

The Electrical Code requires GFCI protection in wet or damp areas such as bathrooms, kitchen countertop receptacles, garages, and outdoors, where shock risk is highest. Bedrooms are covered by arc-fault, not ground-fault, protection, and GFCI is required in many more places than just pools or basements.2025 CA Electrical Code, Article 210 (GFCI protection)

Under typical residential conditions, a 14 AWG copper conductor is generally protected at a MAXIMUM overcurrent device rating of:

• a.15 amperes✓
• b.25 amperes
• c.30 amperes
• d.20 amperes

A 14 AWG copper conductor is normally limited to a 15-amp overcurrent device. 20 amps corresponds to 12 AWG and 30 amps to 10 AWG copper; protecting 14 AWG at those higher ratings would allow the wire to overheat before the breaker trips.2025 CA Electrical Code, Article 240 (Overcurrent Protection)

In a service panel, the main bonding jumper serves PRIMARILY to:

• a.Connect the grounded (neutral) conductor to the equipment grounding system at the service✓
• b.Limit the total number of circuits in the panel so that the bus is not loaded beyond what it was built for
• c.Reduce the voltage supplied to branch circuits so that devices downstream see a lower and steadier level
• d.Increase the amperage available to the building by giving the incoming conductors a second path to carry load

The main bonding jumper ties the grounded (neutral) conductor to the equipment grounding system at the service, establishing the low-impedance fault path that lets breakers clear ground faults. It has nothing to do with limiting circuits, changing voltage, or increasing available amperage.2025 CA Electrical Code, Article 250 (Grounding and Bonding)

In a dwelling kitchen, what is the MINIMUM number of 20-ampere small-appliance branch circuits required to serve the countertop receptacle outlets?

• a.One
• b.Four
• c.Two✓
• d.Three

At least two 20-amp small-appliance branch circuits must serve kitchen countertop receptacles so heavy plug-in loads are divided. One circuit is insufficient under the code, while three or four exceed the required minimum.2025 CA Electrical Code, Article 210 (Branch Circuits)

Using a volume allowance of 2.0 cubic inches per 14 AWG conductor, what is the MINIMUM box volume required for a box containing eight 14 AWG conductors (no devices or clamps)?

• a.16.0 cubic inches✓
• b.14.0 cubic inches
• c.12.0 cubic inches
• d.18.0 cubic inches

Eight conductors x 2.0 cubic inches each = 16.0 cubic inches minimum. The lower figures undercount conductors, and 18.0 overcounts them; box fill must be at least the sum of the individual conductor allowances.2025 CA Electrical Code, Article 314 (Outlet Boxes)

What is the MINIMUM required width of clear working space in front of a service panel or motor control center rated 600 volts or less?

• a.18 inches of clear width in front of the enclosure, regardless of how wide the equipment is
• b.30 inches or the width of the equipment, whichever is greater✓
• c.24 inches
• d.48 inches in all cases, even where the equipment itself is narrower than that

The working space in front of electrical equipment must be at least 30 inches wide, or the width of the equipment if that is greater, so a worker can operate and service it safely. 24 and 18 inches are too narrow, and 48 inches is more than the general minimum required.2025 CA Electrical Code, Article 110 (Working Space)

When a driven ground rod is used as a grounding electrode, what is the MINIMUM length that must be in contact with the soil?

• a.10 feet
• b.6 feet
• c.8 feet✓
• d.4 feet

A ground rod electrode must have at least 8 feet in contact with the soil to reach reliably moist earth and provide a low-resistance connection. 4 and 6 feet are too shallow, and 10 feet exceeds the required minimum length.2025 CA Electrical Code, Article 250 (Grounding Electrodes)

Ampacity derating (adjustment) for bundled conductors generally begins to apply once a raceway or cable contains MORE than how many current-carrying conductors?

• a.Six
• b.Two
• c.Three✓
• d.Nine, assuming smaller bundles never overheat

Adjustment factors apply when more than three current-carrying conductors share a raceway or cable, because bundled conductors cannot shed heat as easily. Two or three conductors do not trigger derating, and waiting until six or nine would allow dangerous overheating.2025 CA Electrical Code, Article 310 (Conductor Ampacity)

Limiting the developed length of a fixture's trap arm (the distance from the trap to its vent) is important PRIMARILY to:

• a.Reduce the amount of pipe material used
• b.Prevent the trap from losing its water seal by self-siphonage✓
• c.Allow the trap to be installed without a cleanout
• d.Increase the flow rate through the fixture

Keeping the trap arm within its maximum length prevents self-siphonage that would pull the water seal out of the trap and let sewer gas enter. It is not primarily about saving pipe, boosting flow, or avoiding cleanouts.2025 CA Plumbing Code, Chapter 9 (Vents)

In a seismic region, a tank-type water heater must generally be secured against movement with a MINIMUM of:

• a.A single strap at the middle of the tank, on the theory that one band at mid-height restrains the whole load
• b.One strap at the base only, since the floor connection is where the tank is assumed to want to slide
• c.Two straps, one in the upper third and one in the lower third of the tank✓
• d.Adhesive pads under the tank feet, relying on the bond to the floor to keep the tank from shifting

Codes in seismic areas require at least two straps, placed in the upper and lower thirds of the tank, to keep it from tipping and shearing gas or water lines during an earthquake. A single strap or base-only strap allows the top to swing, and adhesive pads are not adequate restraint.2025 CA Plumbing Code, Chapter 5 (Water Heaters)

A common device required on an outdoor hose bibb to prevent contaminated water from being drawn back into the potable supply is a:

• a.Water hammer arrestor, which cushions the shock of a valve closing quickly
• b.Pressure-reducing valve
• c.Thermostatic mixing valve, which blends hot and cold water to a set temperature
• d.Hose-bibb (atmospheric) vacuum breaker✓

A hose-bibb vacuum breaker admits air to break any siphon so garden or chemical water cannot be back-siphoned into the potable system. A pressure-reducing valve controls pressure, a water hammer arrestor cushions surges, and a mixing valve blends hot and cold water, none of which prevents backflow.2025 CA Plumbing Code, Chapter 6 (Backflow Protection)

When the static water pressure supplied to a building exceeds what value, a pressure-reducing valve is generally required?

• a.80 psi✓
• b.40 psi
• c.120 psi
• d.60 psi

When static supply pressure exceeds 80 psi, a pressure-reducing valve must be installed to protect fixtures, appliances, and piping. 40 and 60 psi are within the normal usable range, and waiting until 120 psi would leave the system exposed to damaging high pressure.2025 CA Plumbing Code, Chapter 6 (Water Supply)

A 4-inch horizontal building drain runs 48 feet at a minimum slope of 1/8 inch per foot. What is the total fall over that run?

• a.12 inches
• b.8 inches
• c.4 inches
• d.6 inches✓

48 feet x 1/8 inch per foot = 6 inches of total fall. The 4-inch answer uses too little run, 8 inches assumes a steeper 1/6 slope, and 12 inches assumes 1/4 inch per foot rather than the stated 1/8.

Why does the plumbing code prohibit the use of an 'S-trap' on a fixture?

• a.It cannot be connected to plastic pipe
• b.Its configuration tends to self-siphon and lose the trap seal✓
• c.It is too expensive to install
• d.It requires a larger cleanout than a P-trap, so servicing the fixture drain costs more

An S-trap discharges vertically in a way that tends to self-siphon, pulling out the water seal and allowing sewer gas into the building. Cost, pipe material, and cleanout size are not the reason; the prohibition exists because the trap seal cannot be reliably maintained.2025 CA Plumbing Code, Chapter 10 (Traps)

What is the MINIMUM drain size generally required for a water closet (toilet)?

• a.1-1/2 inches
• b.2 inches
• c.4 inches
• d.3 inches✓

A water closet requires a minimum 3-inch drain to carry its solid waste discharge. 1-1/2 and 2 inches are used for smaller fixtures such as lavatories and showers, and 4 inches, while acceptable, is larger than the required minimum for a single toilet.2025 CA Plumbing Code, Chapter 7 (Sanitary Drainage)

When a check valve or pressure-reducing valve creates a 'closed' water system, a thermal expansion tank is required PRIMARILY to:

• a.Reduce noise from the water heater burner during firing cycles
• b.Absorb the pressure increase caused by water expanding as it is heated✓
• c.Filter sediment from the water heater before it reaches fixtures
• d.Increase available hot-water volume for peak demand periods

In a closed system, heated water cannot expand back toward the main, so an expansion tank absorbs the resulting pressure rise and protects the tank and relief valve. It does not add usable hot water, filter sediment, or quiet the burner.2025 CA Plumbing Code, Chapter 6 (Water Supply)

Under current California requirements, newly constructed dwellings must generally provide:

• a.Combustion appliances to supply fresh air, on the idea that their draft pulls outdoor air into the house
• b.Exhaust fans in bathrooms but no whole-house strategy, treating spot ventilation as the complete answer
• c.Operable windows only, with no mechanical ventilation, leaving fresh air to whenever occupants open them
• d.Whole-house mechanical ventilation sized to a minimum airflow✓

California energy and ventilation standards require continuous or intermittent whole-house mechanical ventilation sized to a minimum airflow to maintain indoor air quality in tightly built homes. Operable windows alone are not accepted, local exhaust fans are additional to the whole-house system, and combustion appliances are not a ventilation source.2025 CA Energy Code (Title 24, Part 6) / ASHRAE 62.2

Using the all-outdoor two-permanent-opening method at a rate of 1 square inch per 4,000 Btu/hr per opening, what is the MINIMUM net free area of EACH opening for a 100,000 Btu/hr furnace?

• a.25 square inches✓
• b.50 square inches
• c.10 square inches
• d.100 square inches

100,000 Btu/hr divided by 4,000 = 25 square inches for each of the two openings. 10 and 50 misapply the ratio, and 100 square inches would result from using 1 square inch per 1,000 Btu/hr, which is the indoor-air, not all-outdoor, rate.2025 CA Mechanical Code, Chapter 7 (Combustion Air)

Under the California Energy Code, sealing forced-air duct systems is required PRIMARILY to:

• a.Increase the noise level of the air handler so that occupants can hear whenever the system is running
• b.Eliminate the need for duct insulation
• c.Allow smaller-diameter ducts to be used everywhere in the house, saving space inside framed chases
• d.Limit conditioned-air leakage so the system delivers heating and cooling efficiently✓

Duct sealing (verified by leakage testing) limits the loss of conditioned air so the system delivers the intended heating and cooling efficiently. It is not meant to increase noise, does not by itself allow undersized ducts, and does not remove the separate requirement to insulate ducts in unconditioned spaces.2025 CA Energy Code (Title 24, Part 6)

What is a common MINIMUM intermittent exhaust airflow required for a residential bathroom fan?

• a.150 cfm
• b.50 cfm✓
• c.100 cfm
• d.20 cfm

A bathroom exhaust fan operated intermittently is commonly required to move at least 50 cfm to clear moisture. 20 cfm is the typical continuous rate, while 100 and 150 cfm exceed the minimum required for intermittent bathroom exhaust.2025 CA Mechanical Code, Chapter 4 (Ventilation) / ASHRAE 62.2

What is the typical MINIMUM clearance to combustible materials for a single-wall metal vent connector on a fuel-burning appliance?

• a.6 inches✓
• b.3 inches
• c.12 inches
• d.1 inch

A single-wall metal vent connector typically requires at least 6 inches of clearance to combustibles because its outer surface runs hot. 1 and 3 inches are too close for single-wall pipe, and 12 inches is greater than the standard required clearance.2025 CA Mechanical Code, Chapter 8 (Vents and Connectors)

Under the California Energy Code, a vented range hood over an electric range in a dwelling larger than 1,000 square feet, if it complies by airflow rather than capture efficiency, must move a MINIMUM of:

• a.300 cfm
• b.110 cfm✓
• c.50 cfm
• d.500 cfm

Table 150.0-G requires 110 cfm, or a 50% capture efficiency rating, for a hood over an electric range in a dwelling over 1,000 square feet. The figure rises for smaller dwellings and for gas ranges, up to 280 cfm. 50 cfm is the bathroom rate, 300 cfm is the rate for other kitchen exhaust fans such as downdraft units, and 500 cfm is not in the table.2025 CA Energy Code §150.0(o), Table 150.0-G

A roof has 2,400 square feet of surface area to be covered with three-tab asphalt shingles. At 3 bundles per square (100 sq ft), how many bundles are needed before adding any waste allowance?

• a.24 bundles
• b.72 bundles✓
• c.80 bundles
• d.48 bundles

2,400 sq ft equals 24 squares; 24 x 3 bundles = 72 bundles. The 24 answer counts squares not bundles, 48 uses 2 bundles per square, and 80 adds a waste factor that the question excludes.

Where a sloped shingle roof meets a vertical sidewall, the flashing that is woven in shingle-by-shingle to direct water onto the roof surface is called:

• a.Ridge flashing
• b.Cricket flashing
• c.Step flashing✓
• d.Drip edge

Step flashing consists of individual bent metal pieces layered with each shingle course along a sidewall, directing water back onto the roof. A drip edge is at eaves and rakes, ridge flashing caps the peak, and a cricket diverts water around the upslope side of a chimney.2025 CA Residential Code, Chapter 9 (Roof Assemblies)