NASCLA Accredited Examination for Commercial General Building Contractors — Questions and Answers

Question 1: Which hazard communication requirement mandates that chemical containers on a job site be properly labeled?

OSHA 29 CFR 1926.200
OSHA HazCom Standard 29 CFR 1926.59 (Correct answer)
OSHA 29 CFR 1926.50
OSHA 29 CFR 1926.100

Correct answer: OSHA HazCom Standard 29 CFR 1926.59

OSHA's Hazard Communication Standard (HazCom) at 29 CFR 1926.59 requires proper labeling and Safety Data Sheets for hazardous chemicals.

Question 2: _______ is the name for the foundation, which consists of a thick slab of reinforced cement covering the entire region to support highly concentrated structural loads.

All of the options are correct
Combined footing
Strap footing
Raft footing (Correct answer)

Correct answer: Raft footing

A raft footing, also known as a mat foundation, is a large, continuous slab of reinforced concrete that covers the entire footprint of a structure. This type of foundation is employed when individual footings would cover more than half the building area, or when the soil's bearing capacity is low. It effectively distributes heavy, concentrated structural loads over a much larger area, reducing the pressure exerted on the underlying soil.

Question 3: A cross joint is _______ to the plumb line when it is aligned.

Perpendicular (Correct answer)
Lintel
Vertical line
Bed block

Correct answer: Perpendicular

In masonry construction, a cross joint (also known as a bed joint) is the horizontal mortar joint between courses of bricks or blocks. When properly aligned and constructed, this joint should be perfectly perpendicular to the plumb line, which represents a true vertical. This ensures that the masonry units are laid level, contributing to the wall's structural integrity and aesthetic straightness.

Question 4: What is the purpose of a 'double top plate' in wood-frame wall construction?

To double the wall height capacity
To provide a decorative molding profile
To create a space for electrical wiring
To tie adjacent wall sections together and transfer loads, enabling roof/floor framing to land on wall intersections (Correct answer)

Correct answer: To tie adjacent wall sections together and transfer loads, enabling roof/floor framing to land on wall intersections

The double top plate (two layers of horizontal plates at the top of wall framing) ties intersecting walls together and allows framing members above to land on bearing points even when they don't align with studs below.

Question 5: Which AWG wire size is commonly used for a 20-amp, 120-volt branch circuit?

12 AWG (Correct answer)
8 AWG
14 AWG
10 AWG

Correct answer: 12 AWG

12 AWG copper wire has an ampacity of 20 amps and is the NEC-required minimum size for 20-amp branch circuits.

Question 6: What is the correct mortar type for load-bearing masonry walls?

Type K
Type N
Type O
Type M or S (Correct answer)

Correct answer: Type M or S

ASTM C270 specifies Type M or Type S mortar for load-bearing and below-grade masonry due to their higher compressive strengths.

Question 7: What is the recommended minimum thickness for a residential concrete driveway slab?

2 inches
3 inches
4 inches (Correct answer)
6 inches

Correct answer: 4 inches

ACI recommends a minimum 4-inch thickness for residential concrete driveways to handle typical passenger vehicle loads without excessive cracking.

Question 8: Causes of dampness

Soil solidification
All of the options are incorrect (Correct answer)
Efflorescence
Paint whitening

Correct answer: All of the options are incorrect

Dampness in buildings is typically caused by issues such as rising damp (capillary action from the ground), penetrating damp (water ingress through walls or roof), condensation (moisture in the air), or plumbing leaks. Soil solidification is a ground improvement technique, paint whitening can be a symptom of dampness or other issues, and efflorescence is a symptom of moisture carrying salts to the surface, not a cause of dampness itself. Therefore, none of the listed options are direct causes of dampness.

Question 9: On a structural drawing, what does the symbol 'W12×53' represent?

A wide-flange steel beam 12 inches deep weighing 53 pounds per linear foot (Correct answer)
A wire mesh with 12-inch spacing at 53 pounds
A wall 12 feet wide and 53 feet tall
A wood beam 12 inches by 53 inches

Correct answer: A wide-flange steel beam 12 inches deep weighing 53 pounds per linear foot

W12×53 is the designation for a wide-flange (W-shape) steel beam with a nominal depth of 12 inches and a weight of 53 pounds per linear foot.

Question 10: What does the symbol 'CL' represent on a construction blueprint?

Centerline (Correct answer)
Column Line
Ceiling Line
Closed Loop

Correct answer: Centerline

CL (often shown as a line with alternating long and short dashes) represents the centerline of a structural element or feature on construction drawings.

Question 11: _______ is the style of arch utilized in high-end structures where aesthetics are crucial.

Axed brick arch
Rubble arch
Gauged brick arch
Ashlar arch (Correct answer)

Correct answer: Ashlar arch

An ashlar arch is constructed using finely dressed and accurately cut stones, known as ashlar masonry. These arches are characterized by their precise workmanship, smooth surfaces, and uniform, thin joints. Due to their superior finish and aesthetic appeal, ashlar arches are typically chosen for high-end structures where visual quality and architectural elegance are paramount.

Question 12: What is 'efflorescence' on masonry walls?

A type of mortar joint finish
A decorative masonry pattern
Cracking due to settlement
White salt deposits on the masonry surface caused by water migration (Correct answer)

Correct answer: White salt deposits on the masonry surface caused by water migration

Efflorescence is a white powdery deposit on masonry surfaces caused by water-soluble salts being carried to the surface and left behind as the water evaporates.

Question 13: Which of the following is a leading cause of fatalities in the construction industry according to OSHA's 'Fatal Four'?

Falls (Correct answer)
Heat stroke
Chemical exposure
Repetitive stress injuries

Correct answer: Falls

Falls are number one among OSHA's 'Fatal Four' construction hazards, accounting for about 36% of construction fatalities.

Question 14: What does 'AFF' stand for on construction drawings?

Allowance For Framing
Above Finish Floor (Correct answer)
Adjusted Finish Framework
Architectural Finish Floor

Correct answer: Above Finish Floor

AFF stands for 'Above Finish Floor' and is used to specify the height of fixtures, switches, outlets, and other elements measured from the finished floor surface.

Question 15: ______ is the process of maintaining moisture in finished concrete for a set amount of time.

Curing of concrete (Correct answer)
Finishing of concrete
Placing of concrete
Compaction of concrete

Correct answer: Curing of concrete

Curing of concrete is the essential process of maintaining adequate moisture content and a favorable temperature in freshly placed concrete for a specific period. This allows the cement to fully hydrate, which is crucial for the concrete to develop its intended strength, durability, and other desired engineering properties. Proper curing prevents premature drying and ensures optimal performance.

Question 16: A minimum 15 cm cover is supplied on the ______ in grillage foundations.

Lower beam of lower tier (Correct answer)
The outside beams' ends
All options are incorrect
Exterior beams' ends

Correct answer: Lower beam of lower tier

Grillage foundations consist of a network of steel beams embedded in concrete, designed to distribute heavy column loads over a large area of soil. To protect these steel beams from corrosion and ensure proper load transfer, a minimum concrete cover is required. Specifically, the lower beam of the lower tier, which is closest to the soil, needs a minimum cover of 15 cm (or 6 inches) to provide adequate protection.

Question 17: What type of fire extinguisher should be used on an electrical fire on a construction site?

Class D
Class B
Class C (Correct answer)
Class A

Correct answer: Class C

Class C fire extinguishers use non-conductive agents and are required for electrical fires to prevent electrocution.

Question 18: Choose the appropriate statement from the list below:

The index value known as fineness modulus expresses the relative sizes of both coarse and fine aggregates. (Correct answer)
Both compression and tension are equally powerful forces for plain cement concrete.
Curing concrete is necessary for optimal cement compaction.
Slump test is used to evaluate the strength of concrete.

Correct answer: The index value known as fineness modulus expresses the relative sizes of both coarse and fine aggregates.

The fineness modulus is an empirical index value used in concrete technology to describe the average size of aggregate particles. It is derived from the sieve analysis of both coarse and fine aggregates, providing a quick measure of their overall fineness or coarseness. This value is crucial for concrete mix design, helping to ensure optimal workability, strength, and economy of the mix.

Question 19: What is the purpose of 'hurricane ties' (rafter ties) in roof framing?

To support ceiling joists
To connect rafters to the top plates and resist uplift forces from wind (Correct answer)
To prevent moisture infiltration at the roof edge
To align rafters at the ridge board

Correct answer: To connect rafters to the top plates and resist uplift forces from wind

Hurricane ties (metal connectors) anchor rafters to the wall top plates, providing resistance against wind uplift forces that could lift the roof off the walls.

Question 20: Which wire color is used for the grounding conductor in standard US residential wiring?

Red
Green or bare copper (Correct answer)
Black
White

Correct answer: Green or bare copper

Green insulated wire or bare copper conductor is the NEC-standard color code for equipment grounding conductors.

Question 21: The arrangement created to temporarily support a dangerous structure is called as _______.

Scaffolding
Underpinning
Shoring (Correct answer)
Jacking

Correct answer: Shoring

Shoring is the arrangement created to temporarily support a dangerous or unstable structure, or an excavation, to prevent its collapse. This temporary support system, which can include props, raking shores, or flying shores, is crucial for ensuring safety during repair, alteration, or adjacent construction work.

Question 22: What scale is most commonly used for architectural floor plan drawings?

1/8" = 1'-0"
1" = 10'-0"
1/2" = 1'-0"
1/4" = 1'-0" (Correct answer)

Correct answer: 1/4" = 1'-0"

The most common scale for architectural floor plans is 1/4 inch equals 1 foot, providing enough detail while fitting on standard sheet sizes.

Question 23: What does GFCI stand for in electrical construction?

Ground Fault Circuit Interrupter (Correct answer)
Ground Fault Current Insulator
General Fault Current Indicator
General Fault Circuit Isolator

Correct answer: Ground Fault Circuit Interrupter

GFCI stands for Ground Fault Circuit Interrupter, a device that detects current leakage to ground and trips within milliseconds to prevent electrocution.

Question 24: The capacity of granite to support weight is typically _________.

15 to 20 kg/cm²
42 to 46 kg/cm²
30 to 35 kg/cm² (Correct answer)
40 to 45 kg/cm²

Correct answer: 30 to 35 kg/cm²

Granite is a very dense, strong, and durable igneous rock, making it an excellent material for foundations and structural elements. Its high compressive strength allows it to support significant loads without crushing. The typical bearing capacity of granite ranges from 30 to 35 kg/cm² (approximately 3000 to 3500 kN/m²), which is considerably higher than most other natural stones or soils.

Question 25: What is a 'change order' in construction?

A written modification to the original contract scope, cost, or schedule (Correct answer)
A material delivery receipt
A subcontractor invoice
A daily work log

Correct answer: A written modification to the original contract scope, cost, or schedule

A change order is a written document that formally modifies the original construction contract, including changes to scope, cost, and/or schedule.

Question 26: What is the 'rise over run' in roof framing terminology?

The total roof height over total building width
The ratio of roof span to eave height
The vertical rise in inches for every 12 inches of horizontal run — the roof pitch (Correct answer)
The angle of the rafter cut at the ridge

Correct answer: The vertical rise in inches for every 12 inches of horizontal run — the roof pitch

Roof pitch (rise over run) expresses how many inches the roof rises vertically for every 12 inches of horizontal run, such as 6:12 or 8:12.

Question 27: What type of footing is typically used for a single column load?

Grade beam
Mat footing
Strip footing
Spread (pad) footing (Correct answer)

Correct answer: Spread (pad) footing

A spread footing (also called a pad footing) is an isolated square or rectangular footing designed to distribute a single column load to the soil.

Question 28: What is the purpose of control joints in a concrete slab?

To provide locations where cracking can occur in a controlled manner (Correct answer)
To increase the slab's load capacity
To allow expansion due to heat
To accommodate pipe penetrations

Correct answer: To provide locations where cracking can occur in a controlled manner

Control joints create weakened planes in concrete slabs that guide shrinkage cracking to occur at planned locations rather than randomly across the slab.

Question 29: Which of the following is NOT a type of cave-in protection system recognized by OSHA for excavations?

Trench boxes
Drainage matting (Correct answer)
Shoring
Sloping

Correct answer: Drainage matting

OSHA recognizes sloping, shoring, and trench shields (boxes) as acceptable cave-in protection systems; drainage matting is not a recognized method.

Question 30: The Auger boring technique is inappropriate for _______.

Really tough soil
Concrete soil
Vary soft soil
All of the options are correct (Correct answer)

Correct answer: All of the options are correct

Auger boring is a soil exploration technique that uses a rotating helical screw to bring soil samples to the surface. While effective in many soil types, it is inappropriate for very soft soils where the borehole might collapse, extremely tough soils where the auger cannot penetrate effectively, or concrete soil as it is designed for natural soil, not hardened materials. In such conditions, other drilling methods are required.

Question 31: What is the minimum concrete cover required for rebar in a slab exposed to weather in the US?

3 inches
2 inches
3/4 inch
1-1/2 inches (Correct answer)

Correct answer: 1-1/2 inches

ACI 318 requires a minimum of 1-1/2 inches of concrete cover over reinforcing steel in slabs exposed to weather to protect against corrosion.

NASCLA Accredited Examination for Commercial General Building Contractors

The NASCLA Commercial General Building Contractor exam is a nationally recognized, open-book licensing examination covering construction project planning, building codes, trade practices, OSHA safety, and contractor business law. Accepted for reciprocity in 17+ U.S. states.

Questions

35 min

Time Limit

70%

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