General Contractor License Materials and Methods of Construction 1 — Questions and Answers
Question 1: What is the standard compressive strength (f'c) of normal-weight concrete used in residential foundations?
- 1,500 psi
- 2,500 psi
- 3,000 psi (Correct answer)
- 5,000 psi
Correct answer: 3,000 psi
3,000 psi is the most commonly specified compressive strength for residential foundations, providing adequate load capacity for typical structural demands.
Question 2: Which lumber grade designation indicates the highest structural quality for dimensional framing lumber?
- No. 2
- No. 1
- Select Structural (Correct answer)
- Construction Grade
Correct answer: Select Structural
Select Structural is the highest grade for dimensional lumber, offering the best combination of strength, stiffness, and appearance with minimal defects.
Question 3: What does the designation 'W8x31' refer to in structural steel?
- A wide-flange beam 8 inches deep weighing 31 pounds per linear foot (Correct answer)
- A weld specification requiring 8 passes at 31 amps
- An 8-inch wide plate that is 31 feet long
- A wire rope with 8 strands and a 31-ton load rating
Correct answer: A wide-flange beam 8 inches deep weighing 31 pounds per linear foot
The W designation indicates a wide-flange shape; the first number is the nominal depth in inches, and the second is the weight per linear foot in pounds.
Question 4: Which mortar type is recommended for load-bearing exterior masonry walls in moderate climates?
- Type K
- Type S
- Type N (Correct answer)
- Type M
Correct answer: Type N
Type N mortar (1 part portland cement, 1 part lime, 6 parts sand) provides medium strength and good workability, making it ideal for above-grade exterior load-bearing walls.
Question 5: What is the primary purpose of a vapor retarder installed in a wall assembly?
- To increase the fire resistance rating
- To limit moisture migration into the building envelope (Correct answer)
- To provide additional thermal insulation
- To act as a sound barrier between wall cavities
Correct answer: To limit moisture migration into the building envelope
Vapor retarders control moisture diffusion through wall assemblies, preventing condensation within the envelope that could lead to mold and structural damage.
Question 6: What is the minimum rebar cover required for concrete in direct contact with the earth (cast against earth)?
- 1 inch
- 1.5 inches
- 2 inches
- 3 inches (Correct answer)
Correct answer: 3 inches
ACI 318 requires a minimum of 3 inches of concrete cover for reinforcement cast against and permanently exposed to earth, protecting steel from corrosion.
Question 7: Which roofing underlayment is classified as a self-adhering membrane often used in ice and water shield applications?
- 15-lb felt paper
- 30-lb felt paper
- Rubberized asphalt membrane (Correct answer)
- Synthetic polypropylene sheet
Correct answer: Rubberized asphalt membrane
Rubberized asphalt (SBS-modified) self-adhering membranes bond directly to the deck and self-seal around fasteners, providing superior protection in ice dam and leak-prone areas.
General Contractor License Materials and Methods of Construction 1
What is the standard compressive strength (f'c) of normal-weight concrete used in residential foundations?