CSLB Class B General Contractor's
License - Building's Exam: Core Trades
(Part 2) (2025)
When drilling a 2 x 4 the minimum distance from the edge to the hole should be: -
✔️✔️5/8"
What is the minimum size a water supply pipe to a building? - ✔️✔️0.75 inches
When do you wet a concrete block during installation? - ✔️✔️Never
What is the minimum slope of a finished shower floor? - ✔️✔️1/8 inch per foot
What is used to connect a roof rafter to a ridge member?
A) Tie clip
B) Poly flange
C) Clip angle
D) VPC - ✔️✔️C) Clip angle
(According to Title 24, Roof rafters shall be connected to a ridge member with a
minimum 2 inch by 2 inch clip angle with No. 10 screws to the ridge member. In
addition, Rafters shall be framed not more than 1-1/2-inch (38 mm) offset from each
other to ridge board or directly opposite from each other with a gusset plate as a tie.
Ridge board shall be not less than 1-inch (25 mm) nominal thickness and not less in
depth than the cut end of the rafter. At valleys and hips there shall be a valley or hip
rafter not less than 2-inch (51 mm) nominal thickness and not less in depth than the cut
end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a
bearing partition or be designed to carry and distribute the specific load at that point.
Where the roof pitch is less than three units vertical in 12 units horizontal (25-percent
slope), structural members that support rafters and
What does material compatibility refer to when installing alternate water sources in
existing plumbing systems?
A) Plumbing fixtures have to come from the same manufacturer
B) Only the couplings must be made of metal
C) All plumbing connections must be soldered or brazed
D) Use of materials that are compatible with the type of pipe and fitting materials -
✔️✔️D) Use of materials that are compatible with the type of pipe and fitting materials
,When you have a gap in the building envelope, what do you do to prevent air leakage?
A) Stuff insulation into gaps
B) Put caulking in and around the gaps
C) Weather seal, weather strip, and apply caulking
D) Nothing, all buildings require air leakage - ✔️✔️C) Weather seal, weather strip, and
apply caulking
In order to protect a water heater from damage, what is the minimum height it should be
from the floor of a garage? - ✔️✔️18 inches
How many plumbing fixtures can be vented by a single vertical wet-vent? - ✔️✔️4
(According to the California Plumbing Code, the vertical piping between two consecutive
inlet levels shall be considered a wet-vented section. Each wet-vented section shall be
not less than one pipe size exceeding the required minimum waste pipe size of the
upper fixture or shall be one pipe size exceeding the required minimum pipe size for the
sum of the fixture units served by such wet-vented section, whichever is larger, but no
case less than 2 inches.)
After the construction of a new home you turn on the faucet in the kitchen and the water
pressure is extremely low, how should you proceed to test the problem?
A) Call the inspector
B) Hire a plumbing contractor
C) Turn on the light switch
D) Inspect the tank and pump for mechanical problems - ✔️✔️D) Inspect the tank and
pump for mechanical problems
Section 408.5 of the California Plumbing Code states that the finished floor of the
receptor should slope uniformly from the sides towards the drain, not less than 1/8 inch
per foot, nor more than 1/2 inch per foot. For further clarification, the California
Plumbing Code refers to field-fabricated shower pans as "receptors." It is important not
to confuse the requirements in CPC 408.5 with CPC 408.7, which specifies that the
lining materials for showers and receptors should be pitched ¼ inch per foot towards
weep holes in the subdrain of a smooth and solidly formed subbase.
Who is responsible for final approval of plans on a public works project?
A) Engineer
B) Homeowner
C) City
D) Contractor - ✔️✔️A) Engineer
, Ventilation openings for foundations are at least ____ for every 150 square feet of
under-floor area. - ✔️✔️1 square foot
(According to Title 24, the minimum net area of ventilation openings shall be not less
than 1 square foot for each 150 square feet of under-floor area. One ventilation opening
shall be within 3 feet of each corner of the building. Ventilation openings shall be
covered for their height and width with any of the following materials provided that the
least dimension of the covering shall not exceed 1/4 inch.)
A contractor is very cautious when adding water to concrete, why?
A) It ruins the consistency
B) Reduces the strength
C) Produces cracks
D) All of the above - ✔️✔️D) All of the above
Which of the following directly affect the "load of the envelope"?
A) Ambient conditions
B) Architecture
C) Occupants
D) All of the above - ✔️✔️D) All of the above
The envelope of the conditioned space is essentially the barrier between the exterior
elements and the interior conditioned living space. Anything that can cause influences
the envelope will affect its load, with respect to air conditioning and energy usage.
If time is of the essence, which of the following is best at unclogging drains?
A) Coat hanger
B) Power drill
C) Chemical products
D) Snake - ✔️✔️D) Snake
Which of the following is used to test for gas leaks?
A) Matches
B) Deionized water
C) Non-corrosive liquid
D) None of the above - ✔️✔️C) Non-corrosive liquid
After shutting off the gas from the source what should be done prior to the removal of
gas pipe?
A) Purge it with acetylene
B) Purge it with refrigerant
License - Building's Exam: Core Trades
(Part 2) (2025)
When drilling a 2 x 4 the minimum distance from the edge to the hole should be: -
✔️✔️5/8"
What is the minimum size a water supply pipe to a building? - ✔️✔️0.75 inches
When do you wet a concrete block during installation? - ✔️✔️Never
What is the minimum slope of a finished shower floor? - ✔️✔️1/8 inch per foot
What is used to connect a roof rafter to a ridge member?
A) Tie clip
B) Poly flange
C) Clip angle
D) VPC - ✔️✔️C) Clip angle
(According to Title 24, Roof rafters shall be connected to a ridge member with a
minimum 2 inch by 2 inch clip angle with No. 10 screws to the ridge member. In
addition, Rafters shall be framed not more than 1-1/2-inch (38 mm) offset from each
other to ridge board or directly opposite from each other with a gusset plate as a tie.
Ridge board shall be not less than 1-inch (25 mm) nominal thickness and not less in
depth than the cut end of the rafter. At valleys and hips there shall be a valley or hip
rafter not less than 2-inch (51 mm) nominal thickness and not less in depth than the cut
end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a
bearing partition or be designed to carry and distribute the specific load at that point.
Where the roof pitch is less than three units vertical in 12 units horizontal (25-percent
slope), structural members that support rafters and
What does material compatibility refer to when installing alternate water sources in
existing plumbing systems?
A) Plumbing fixtures have to come from the same manufacturer
B) Only the couplings must be made of metal
C) All plumbing connections must be soldered or brazed
D) Use of materials that are compatible with the type of pipe and fitting materials -
✔️✔️D) Use of materials that are compatible with the type of pipe and fitting materials
,When you have a gap in the building envelope, what do you do to prevent air leakage?
A) Stuff insulation into gaps
B) Put caulking in and around the gaps
C) Weather seal, weather strip, and apply caulking
D) Nothing, all buildings require air leakage - ✔️✔️C) Weather seal, weather strip, and
apply caulking
In order to protect a water heater from damage, what is the minimum height it should be
from the floor of a garage? - ✔️✔️18 inches
How many plumbing fixtures can be vented by a single vertical wet-vent? - ✔️✔️4
(According to the California Plumbing Code, the vertical piping between two consecutive
inlet levels shall be considered a wet-vented section. Each wet-vented section shall be
not less than one pipe size exceeding the required minimum waste pipe size of the
upper fixture or shall be one pipe size exceeding the required minimum pipe size for the
sum of the fixture units served by such wet-vented section, whichever is larger, but no
case less than 2 inches.)
After the construction of a new home you turn on the faucet in the kitchen and the water
pressure is extremely low, how should you proceed to test the problem?
A) Call the inspector
B) Hire a plumbing contractor
C) Turn on the light switch
D) Inspect the tank and pump for mechanical problems - ✔️✔️D) Inspect the tank and
pump for mechanical problems
Section 408.5 of the California Plumbing Code states that the finished floor of the
receptor should slope uniformly from the sides towards the drain, not less than 1/8 inch
per foot, nor more than 1/2 inch per foot. For further clarification, the California
Plumbing Code refers to field-fabricated shower pans as "receptors." It is important not
to confuse the requirements in CPC 408.5 with CPC 408.7, which specifies that the
lining materials for showers and receptors should be pitched ¼ inch per foot towards
weep holes in the subdrain of a smooth and solidly formed subbase.
Who is responsible for final approval of plans on a public works project?
A) Engineer
B) Homeowner
C) City
D) Contractor - ✔️✔️A) Engineer
, Ventilation openings for foundations are at least ____ for every 150 square feet of
under-floor area. - ✔️✔️1 square foot
(According to Title 24, the minimum net area of ventilation openings shall be not less
than 1 square foot for each 150 square feet of under-floor area. One ventilation opening
shall be within 3 feet of each corner of the building. Ventilation openings shall be
covered for their height and width with any of the following materials provided that the
least dimension of the covering shall not exceed 1/4 inch.)
A contractor is very cautious when adding water to concrete, why?
A) It ruins the consistency
B) Reduces the strength
C) Produces cracks
D) All of the above - ✔️✔️D) All of the above
Which of the following directly affect the "load of the envelope"?
A) Ambient conditions
B) Architecture
C) Occupants
D) All of the above - ✔️✔️D) All of the above
The envelope of the conditioned space is essentially the barrier between the exterior
elements and the interior conditioned living space. Anything that can cause influences
the envelope will affect its load, with respect to air conditioning and energy usage.
If time is of the essence, which of the following is best at unclogging drains?
A) Coat hanger
B) Power drill
C) Chemical products
D) Snake - ✔️✔️D) Snake
Which of the following is used to test for gas leaks?
A) Matches
B) Deionized water
C) Non-corrosive liquid
D) None of the above - ✔️✔️C) Non-corrosive liquid
After shutting off the gas from the source what should be done prior to the removal of
gas pipe?
A) Purge it with acetylene
B) Purge it with refrigerant
