Licensing Examination Practice

Illinois Stucco and Plaster Contractor Licensing Examination Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• Which of the following is the primary purpose of a scratch coat in a

three-coat stucco system?

• Provide decorative texture
• Seal the surface from moisture
• Create a key for the brown coat
• Act as the final finish

Rationale: The scratch coat provides a rough surface, or “key,” to

which the brown coat adheres.

• What is the typical minimum thickness of a scratch coat in exterior

stucco applications? 1 / 4

• 1/4 inch
• 3/8 inch
• 1/2 inch
• 5/8 inch

Rationale: The scratch coat is typically applied at 3/8 inch to ensure

proper adhesion and cracking control.

• Which material is commonly used as a reinforcing mesh in plaster

systems over lath?

• Paper
• Plastic
• Metal lath
• Wood

Rationale: Metal lath provides structural support for the plaster and

helps prevent cracking.

• When applying plaster over metal lath, how should the lath be

fastened?

• Using adhesive
• Using nails into drywall
• Using galvanized staples or nails spaced per code
• Simply resting it on the wall

Rationale: Metal lath must be securely fastened with galvanized

nails or staples to maintain stability. 2 / 4

• Which of the following is the main purpose of the brown coat in a

three-coat stucco system?

• Decorative finish
• Base scratch coat
• Leveling and strengthening layer
• Moisture barrier

Rationale: The brown coat is applied to level the surface and add

strength before the finish coat.

6. Portland cement in stucco provides:

• Color
• Strength and durability
• Flexibility
• Water repellency

Rationale: Portland cement reacts with water to form a hard,

durable surface that resists weathering.

• Which type of lath is best for exterior stucco on wood framing?
• Paper lath
• Expanded metal lath
• Gypsum board
• Plastic mesh

Rationale: Expanded metal lath is durable, provides good keying, and

is code-approved for exterior stucco on wood. 3 / 4

• What is the recommended curing time for a scratch coat before

applying the brown coat?

• 1 day
• 24 to 48 hours
• 12 hours
• 7 days

Rationale: The scratch coat should cure 24-48 hours to prevent

cracking and ensure proper bond.

• Which additive can be used to improve adhesion and water retention

in stucco?

• Lime
• Sand
• Acrylic bonding agent
• Gravel

Rationale: Acrylic bonding agents enhance adhesion to the substrate

and improve flexibility.

• What is the maximum recommended thickness for a single coat

of plaster over lath?

• 1 inch
• 3/4 inch
• 5/8 inch
• 1/2 inch
• / 4