CSLB Class B General Contractor's License - Building's Exam: Core Trades (Part 2) (2025) Questions And Answers With Latest Updates

CSLB Class B General Contractor's License - Building's Exam: Core Trades (Part 2) (2025) Questions And Answers With Latest Updates 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 - 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 - 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 - 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 - 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. - ANSWER -10 Which roof assembly has the best fire rating? A) Class A B) Class B C) Class I D) Class III - 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 - 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 - 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? - ANSWER -18 inches How many plumbing fixtures can be vented by a single vertical wet-vent? - 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 - 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: - ANSWER -5/8" What is the minimum size a water supply pipe to a building? - ANSWER -0.75 inches When do you wet a concrete block during installation? - ANSWER -Never What is the minimum slope of a finished shower floor? - ANSWER -1/8 inch per foot 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 - ANSWER -A) Engineer Ventilation openings for foundations are at least ____ for every 150 square feet of under-floor area. - ANSWER -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 - ANSWER -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 - ANSWER -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 - ANSWER -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 - ANSWER -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 C) Purge it with water D) Purge it with expanding foam - ANSWER -C) Purge it with water According to the California Mechanical Code, where piping containing gas is to be removed, the line shall be first disconnected from sources of gas then thoroughly purged with air, water or inert gas before cutting or welding is done. Automatic sprinkler systems can be installed in residential occupancies including 4 stories in height in buildings NOT exceeding ___ feet in height. - ANSWER -60 In order to purchase and handle more than ___________ of refrigeration, a technician must possess an EPA certification for each type of refrigerant handled. - ANSWER -20 lbs. When installing primary condensate drains for evaporative coils and high efficiency furnaces, ______________must be provided at the highest point on the condensate line. A) Support strap