New York Plasterer License Examination
Practice Questions Exam (LATEST
UPDATE 2026) already graded
A+||GUARANTEED PASS
Question 1
A plasterer is applying a traditional three-coat plaster system over metal lath. Which coat is
primarily responsible for embedding into the lath and creating a mechanical bond?
A. Finish coat
B. Scratch coat
C. Brown coat
D. Veneer coat
Answer: B. Scratch coat
Rationale:
The scratch coat is the first coat applied over lath. It is pushed through the lath openings so it
forms “keys” behind the lath, creating a strong mechanical bond. The coat is then scratched to
provide a rough surface for the brown coat.
Question 2
A wall measures 12 ft high and 18 ft long. If plaster is applied at 3/8 inch thickness and one
bag covers 100 sq ft, how many bags are required?
A. 2
B. 3
C. 4
D. 5
Answer: B. 3
,Rationale:
Wall area = 12 × 18 = 216 sq ft
Coverage per bag = 100 sq ft
216 ÷ 100 = 2.16, which must be rounded up to 3 bags.
Question 3
What is the primary purpose of dampening a masonry surface before plaster application?
A. Prevent plaster discoloration
B. Reduce rapid moisture absorption
C. Increase plaster hardness
D. Speed curing time
Answer: B. Reduce rapid moisture absorption
Rationale:
Dry masonry can quickly absorb water from fresh plaster, leading to poor bonding and cracking.
Dampening slows absorption and allows proper curing.
Question 4
Which condition most commonly causes plaster delamination from concrete surfaces?
A. Excess sand in mix
B. Poor surface preparation
C. Low humidity
D. Proper curing
Answer: B. Poor surface preparation
Rationale:
Concrete surfaces must be clean, roughened, or treated with bonding agents. Dust, oil, or
smooth surfaces prevent adhesion.
Question 5
Which tool is used to level and straighten plaster after it has been applied but before final
finishing?
, A. Darby
B. Hawk
C. Corner trowel
D. Mixing paddle
Answer: A. Darby
Rationale:
A darby is a long straight tool used to level plaster and remove high spots before finishing.
Question 6
When installing metal lath, the lath sheets should typically overlap by:
A. 1/2 inch
B. 1 inch
C. 2 inches
D. 6 inches
Answer: C. 2 inches
Rationale:
A 2-inch overlap provides sufficient reinforcement and prevents cracking along seams.
Question 7
A plaster mix contains too much water. What is the most likely result?
A. Increased bonding strength
B. Reduced shrinkage
C. Cracking and reduced strength
D. Faster curing
Answer: C. Cracking and reduced strength
Rationale:
Excess water weakens the plaster matrix and causes shrinkage during drying, which leads to
cracks.
Question 8
Practice Questions Exam (LATEST
UPDATE 2026) already graded
A+||GUARANTEED PASS
Question 1
A plasterer is applying a traditional three-coat plaster system over metal lath. Which coat is
primarily responsible for embedding into the lath and creating a mechanical bond?
A. Finish coat
B. Scratch coat
C. Brown coat
D. Veneer coat
Answer: B. Scratch coat
Rationale:
The scratch coat is the first coat applied over lath. It is pushed through the lath openings so it
forms “keys” behind the lath, creating a strong mechanical bond. The coat is then scratched to
provide a rough surface for the brown coat.
Question 2
A wall measures 12 ft high and 18 ft long. If plaster is applied at 3/8 inch thickness and one
bag covers 100 sq ft, how many bags are required?
A. 2
B. 3
C. 4
D. 5
Answer: B. 3
,Rationale:
Wall area = 12 × 18 = 216 sq ft
Coverage per bag = 100 sq ft
216 ÷ 100 = 2.16, which must be rounded up to 3 bags.
Question 3
What is the primary purpose of dampening a masonry surface before plaster application?
A. Prevent plaster discoloration
B. Reduce rapid moisture absorption
C. Increase plaster hardness
D. Speed curing time
Answer: B. Reduce rapid moisture absorption
Rationale:
Dry masonry can quickly absorb water from fresh plaster, leading to poor bonding and cracking.
Dampening slows absorption and allows proper curing.
Question 4
Which condition most commonly causes plaster delamination from concrete surfaces?
A. Excess sand in mix
B. Poor surface preparation
C. Low humidity
D. Proper curing
Answer: B. Poor surface preparation
Rationale:
Concrete surfaces must be clean, roughened, or treated with bonding agents. Dust, oil, or
smooth surfaces prevent adhesion.
Question 5
Which tool is used to level and straighten plaster after it has been applied but before final
finishing?
, A. Darby
B. Hawk
C. Corner trowel
D. Mixing paddle
Answer: A. Darby
Rationale:
A darby is a long straight tool used to level plaster and remove high spots before finishing.
Question 6
When installing metal lath, the lath sheets should typically overlap by:
A. 1/2 inch
B. 1 inch
C. 2 inches
D. 6 inches
Answer: C. 2 inches
Rationale:
A 2-inch overlap provides sufficient reinforcement and prevents cracking along seams.
Question 7
A plaster mix contains too much water. What is the most likely result?
A. Increased bonding strength
B. Reduced shrinkage
C. Cracking and reduced strength
D. Faster curing
Answer: C. Cracking and reduced strength
Rationale:
Excess water weakens the plaster matrix and causes shrinkage during drying, which leads to
cracks.
Question 8
