CSLB Class B General Contractor's
License - Building's Exam: Core Trades
(Part 2) Q&A 100% Solved
What is the minimum drain pipe size for the toilet in a residential home? -
✔✔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 - ✔✔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
1
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
,D) Use a pressurized air canister - ✔✔C) Clean the surface using a power
tool
Which personal lift is not acceptable?
A) Scissor
B) Boom
C) Manual
D) Endless rope lift - ✔✔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 - ✔✔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
2
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
,D) Collar tie - ✔✔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 - ✔✔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
3
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
, 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 - ✔✔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. - ✔✔10
Which roof assembly has the best fire rating?
A) Class A
B) Class B
C) Class I
D) Class III - ✔✔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
4
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
License - Building's Exam: Core Trades
(Part 2) Q&A 100% Solved
What is the minimum drain pipe size for the toilet in a residential home? -
✔✔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 - ✔✔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
1
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
,D) Use a pressurized air canister - ✔✔C) Clean the surface using a power
tool
Which personal lift is not acceptable?
A) Scissor
B) Boom
C) Manual
D) Endless rope lift - ✔✔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 - ✔✔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
2
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
,D) Collar tie - ✔✔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 - ✔✔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
3
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
, 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 - ✔✔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. - ✔✔10
Which roof assembly has the best fire rating?
A) Class A
B) Class B
C) Class I
D) Class III - ✔✔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
4
©JOSHCLAY 2024/2025. YEAR PUBLISHED 2024.
