CSLB CLASS B GENERAL
CONTRACTOR'S LICENSE -
BUILDING'S EXAM- CORE TRADES
(PART 2) QUESTIONS & ACCURATE
CORRECT ANSWERS
What is the minimum drain pipe size for the toilet in a residential home? - Correct
Answer ✔✔ 3 inches
Who is licensed to install residential fire sprinkler systems?
A) Plumbing contractor
B) Fire protection contractor
C) General Building contractor
D) Pipeline contractor - Correct Answer ✔✔ B) Fire protection contractor
When brazing or soldering gas pipes during the installation of water heaters, what is the
best way to prepare the pipe?
A) Clean it with water
B) Blow into the pipe using your lungs
C) Clean the surface using a power tool
D) Use a pressurized air canister - Correct Answer ✔✔ C) Clean the surface using a
power tool
Which personal lift is not acceptable?
A) Scissor
B) Boom
C) Manual
D) Endless rope lift - Correct Answer ✔✔ D) Endless rope lift
What is the purpose of PVC primer?
A) To glue PVC pipes to other materials
B) To soften PVC pipe before applying PVC cement
C) To prevent electrical shock
D) To help solder conduit or piping - Correct Answer ✔✔ B) To soften PVC pipe before
applying PVC cement
,What is the most common location to find a roof leak?
A) Attic
B) Shingles
C) Flashing
D) Collar tie - Correct Answer ✔✔ C) Flashing
(Leaks are most common when two surfaces meet or around fenestration. Leaks are
most prominent in valley flashing and improperly installed window flashing.)
What is the most common reason for noise in piping when a water fixture is turned on or
off?
A) Hot water was used
B) Cold water was used
C) Pipe supports come into contact with metal piping
D) The walls are not up to code causing pipe failure - Correct Answer ✔✔ C) Pipe
supports come into contact with metal piping
(Mainly due to water hammer.)
If you send your employee to purchase a 2-inch water supply valve and they return with
a 1.5-inch supply valve, then what is the proper composition of the valve?
A) The casing must be made of plastic
B) The employee must return and purchase a wrought iron valve
C) Brass type
D) The connection must be silver and body made of iron - Correct Answer ✔✔ C) Brass
type
When penetrating a roof with an exhaust, the exhaust must be no closer than _____
feet to any air intake or openable window. - Correct Answer ✔✔ 10
Which roof assembly has the best fire rating?
A) Class A
B) Class B
C) Class I
D) Class III - Correct Answer ✔✔ A) Class A
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 -
Correct Answer ✔✔ 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 - Correct Answer ✔✔ 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? - Correct Answer ✔✔ 18 inches
How many plumbing fixtures can be vented by a single vertical wet-vent? - Correct
Answer ✔✔ 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 - Correct Answer ✔✔ D) Inspect
the tank and pump for mechanical problems
When drilling a 2 x 4 the minimum distance from the edge to the hole should be: -
Correct Answer ✔✔ 5/8"
What is the minimum size a water supply pipe to a building? - Correct Answer ✔✔ 0.75
inches
When do you wet a concrete block during installation? - Correct Answer ✔✔ Never
What is the minimum slope of a finished shower floor? - Correct Answer ✔✔ 1/8 inch
per foot
CONTRACTOR'S LICENSE -
BUILDING'S EXAM- CORE TRADES
(PART 2) QUESTIONS & ACCURATE
CORRECT ANSWERS
What is the minimum drain pipe size for the toilet in a residential home? - Correct
Answer ✔✔ 3 inches
Who is licensed to install residential fire sprinkler systems?
A) Plumbing contractor
B) Fire protection contractor
C) General Building contractor
D) Pipeline contractor - Correct Answer ✔✔ B) Fire protection contractor
When brazing or soldering gas pipes during the installation of water heaters, what is the
best way to prepare the pipe?
A) Clean it with water
B) Blow into the pipe using your lungs
C) Clean the surface using a power tool
D) Use a pressurized air canister - Correct Answer ✔✔ C) Clean the surface using a
power tool
Which personal lift is not acceptable?
A) Scissor
B) Boom
C) Manual
D) Endless rope lift - Correct Answer ✔✔ D) Endless rope lift
What is the purpose of PVC primer?
A) To glue PVC pipes to other materials
B) To soften PVC pipe before applying PVC cement
C) To prevent electrical shock
D) To help solder conduit or piping - Correct Answer ✔✔ B) To soften PVC pipe before
applying PVC cement
,What is the most common location to find a roof leak?
A) Attic
B) Shingles
C) Flashing
D) Collar tie - Correct Answer ✔✔ C) Flashing
(Leaks are most common when two surfaces meet or around fenestration. Leaks are
most prominent in valley flashing and improperly installed window flashing.)
What is the most common reason for noise in piping when a water fixture is turned on or
off?
A) Hot water was used
B) Cold water was used
C) Pipe supports come into contact with metal piping
D) The walls are not up to code causing pipe failure - Correct Answer ✔✔ C) Pipe
supports come into contact with metal piping
(Mainly due to water hammer.)
If you send your employee to purchase a 2-inch water supply valve and they return with
a 1.5-inch supply valve, then what is the proper composition of the valve?
A) The casing must be made of plastic
B) The employee must return and purchase a wrought iron valve
C) Brass type
D) The connection must be silver and body made of iron - Correct Answer ✔✔ C) Brass
type
When penetrating a roof with an exhaust, the exhaust must be no closer than _____
feet to any air intake or openable window. - Correct Answer ✔✔ 10
Which roof assembly has the best fire rating?
A) Class A
B) Class B
C) Class I
D) Class III - Correct Answer ✔✔ A) Class A
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 -
Correct Answer ✔✔ 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 - Correct Answer ✔✔ 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? - Correct Answer ✔✔ 18 inches
How many plumbing fixtures can be vented by a single vertical wet-vent? - Correct
Answer ✔✔ 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 - Correct Answer ✔✔ D) Inspect
the tank and pump for mechanical problems
When drilling a 2 x 4 the minimum distance from the edge to the hole should be: -
Correct Answer ✔✔ 5/8"
What is the minimum size a water supply pipe to a building? - Correct Answer ✔✔ 0.75
inches
When do you wet a concrete block during installation? - Correct Answer ✔✔ Never
What is the minimum slope of a finished shower floor? - Correct Answer ✔✔ 1/8 inch
per foot
