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New Mexico Residential Building Contractor
(GB-2) Practice Exam
1. What is the minimum ceiling height for habitable rooms according to standard building codes?
A. 6’8”
B. 7’0”
C. 7’6”
D. 8’0”
Answer: B
Rationale: Most building codes, including New Mexico, require a minimum ceiling height of
7’0” for habitable spaces.
2. Which soil condition requires a deeper foundation?
A. Dense clay
B. Sandy, loose soil
C. Rocky soil
D. Compacted gravel
Answer: B
Rationale: Loose sandy soil has lower load-bearing capacity and requires deeper footings.
3. When installing electrical wiring, what is the required minimum distance from the finished
floor to outlets in residential areas?
A. 12 inches
B. 18 inches
C. 24 inches
D. 36 inches
Answer: B
Rationale: NEC and residential codes generally require outlets to be at least 18 inches above the
floor.
UPDATED exam 2026
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4. Which fire-resistance rating is typically required for a wall separating a garage from a dwelling
unit?
A. 1 hour
B. 30 minutes
C. 2 hours
D. No rating required
Answer: B
Rationale: A 1/2-hour (30-minute) fire-resistance wall is required to protect the dwelling from
garage fires.
5. Which type of insulation is best for exterior walls in cold climates?
A. Batt fiberglass
B. Spray foam
C. Rigid foam board
D. Loose-fill cellulose
Answer: B
Rationale: Spray foam provides superior R-value and air sealing for exterior walls.
6. When framing a residential roof, the maximum allowable spacing for ceiling joists typically is:
A. 12 inches on center
B. 16 inches on center
C. 24 inches on center
D. 32 inches on center
Answer: C
Rationale: Ceiling joist spacing depends on joist size and span; 24 inches is common for
residential construction.
7. Which type of footing is most common for a single-family home on stable soil?
A. Spread footing
B. Pile foundation
C. Caisson foundation
D. Floating mat slab
UPDATED exam 2026
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Answer: A
Rationale: Spread footings distribute the load directly to the soil and are standard in residential
construction.
8. The proper slope for residential roof drainage is:
A. 1/4 inch per foot
B. 1/2 inch per foot
C. 1 inch per foot
D. 2 inches per foot
Answer: A
Rationale: Minimum slope for most residential roofs is 1/4 inch per foot to ensure proper
drainage.
9. Which type of lumber is recommended for pressure-treated exterior deck framing?
A. SPF (Spruce-Pine-Fir)
B. Redwood
C. Hem-Fir
D. Southern Yellow Pine
Answer: D
Rationale: Southern Yellow Pine is commonly used and treated for outdoor applications due to
its durability.
10. What is the minimum required width for a residential stairway?
A. 30 inches
B. 32 inches
C. 36 inches
D. 40 inches
Answer: C
Rationale: Residential building codes require a minimum stair width of 36 inches for safety.
UPDATED exam 2026
New Mexico Residential Building Contractor
(GB-2) Practice Exam
1. What is the minimum ceiling height for habitable rooms according to standard building codes?
A. 6’8”
B. 7’0”
C. 7’6”
D. 8’0”
Answer: B
Rationale: Most building codes, including New Mexico, require a minimum ceiling height of
7’0” for habitable spaces.
2. Which soil condition requires a deeper foundation?
A. Dense clay
B. Sandy, loose soil
C. Rocky soil
D. Compacted gravel
Answer: B
Rationale: Loose sandy soil has lower load-bearing capacity and requires deeper footings.
3. When installing electrical wiring, what is the required minimum distance from the finished
floor to outlets in residential areas?
A. 12 inches
B. 18 inches
C. 24 inches
D. 36 inches
Answer: B
Rationale: NEC and residential codes generally require outlets to be at least 18 inches above the
floor.
UPDATED exam 2026
,2|Page
4. Which fire-resistance rating is typically required for a wall separating a garage from a dwelling
unit?
A. 1 hour
B. 30 minutes
C. 2 hours
D. No rating required
Answer: B
Rationale: A 1/2-hour (30-minute) fire-resistance wall is required to protect the dwelling from
garage fires.
5. Which type of insulation is best for exterior walls in cold climates?
A. Batt fiberglass
B. Spray foam
C. Rigid foam board
D. Loose-fill cellulose
Answer: B
Rationale: Spray foam provides superior R-value and air sealing for exterior walls.
6. When framing a residential roof, the maximum allowable spacing for ceiling joists typically is:
A. 12 inches on center
B. 16 inches on center
C. 24 inches on center
D. 32 inches on center
Answer: C
Rationale: Ceiling joist spacing depends on joist size and span; 24 inches is common for
residential construction.
7. Which type of footing is most common for a single-family home on stable soil?
A. Spread footing
B. Pile foundation
C. Caisson foundation
D. Floating mat slab
UPDATED exam 2026
, 3|Page
Answer: A
Rationale: Spread footings distribute the load directly to the soil and are standard in residential
construction.
8. The proper slope for residential roof drainage is:
A. 1/4 inch per foot
B. 1/2 inch per foot
C. 1 inch per foot
D. 2 inches per foot
Answer: A
Rationale: Minimum slope for most residential roofs is 1/4 inch per foot to ensure proper
drainage.
9. Which type of lumber is recommended for pressure-treated exterior deck framing?
A. SPF (Spruce-Pine-Fir)
B. Redwood
C. Hem-Fir
D. Southern Yellow Pine
Answer: D
Rationale: Southern Yellow Pine is commonly used and treated for outdoor applications due to
its durability.
10. What is the minimum required width for a residential stairway?
A. 30 inches
B. 32 inches
C. 36 inches
D. 40 inches
Answer: C
Rationale: Residential building codes require a minimum stair width of 36 inches for safety.
UPDATED exam 2026
