Contractor Exam Questions And

CA D87 Waterproof Deck Coating Contractor Exam Questions And Correct Answers (Verified Answers) Plus Rationale2026 Q&A| Instant Download Pdf

• What is the primary purpose of a waterproof deck coating?
• To improve aesthetics
• To increase traction
• To prevent water penetration
• To reduce noise

Rationale: The main function of a waterproof deck coating is to

prevent water from seeping into the deck structure, which can cause damage over time.

• Which of the following substrates is most suitable for a cementitious

waterproof coating?

• Wood
• Steel
• Concrete
• Asphalt

Rationale: Cementitious waterproof coatings are designed for

concrete surfaces due to their strong adhesion and compatibility with cement-based materials.

• What is the recommended minimum slope for a deck to ensure proper

drainage?

• 1%
• 2%

C. 5% 1 / 3

D. 10%

Rationale: A minimum slope of 2% ensures water will drain

effectively off the deck and reduces the risk of ponding.

4. Before applying a waterproof coating, the surface should be:

• Wet
• Clean and dry
• Painted
• Oiled

Rationale: The deck surface must be clean and dry to ensure proper

adhesion of the waterproof coating.

• Which test is commonly used to check the adhesion of a waterproof

coating?

• Hardness test
• Thickness test
• Pull-off test
• Flexibility test

Rationale: The pull-off test measures the tensile strength of the

coating’s adhesion to the substrate.

• When applying a liquid-applied waterproof coating, what is the ideal

number of coats?

• 1

B. 2-3

C. 4-5

D. 6-7

Rationale: Two to three coats ensure complete coverage and an

adequate waterproof membrane.

• Which of the following is a common problem caused by improper deck

waterproofing?

• Fading paint
• Structural decay
• Noise
• Increased traction

Rationale: Water infiltration can lead to wood rot, concrete spalling,

or corrosion in structural components.

8. A primer is applied before waterproof coating primarily to:

• Speed up drying
• Make the surface shiny 2 / 3

• Enhance adhesion
• Reduce costs

Rationale: Primers improve the bonding between the substrate and

the waterproof coating.

• What is the ideal temperature range for applying most liquid deck

waterproof coatings?

A. 0-10°C

B. 10-35°C

C. 35-50°C

• Any temperature

Rationale: Applying the coating within 10-35°C ensures proper

curing and performance.

• Which type of waterproof deck coating is most flexible and

suitable for movements or cracks in the deck?

• Cementitious
• Epoxy
• Polyurethane
• Acrylic

Rationale: Polyurethane coatings remain flexible, allowing the deck

to expand or contract without cracking.

• When should a deck be repaired before waterproof coating

application?

• Only if painted
• Whenever there are cracks, spalls, or damaged areas
• Only in wet areas
• Never

Rationale: Repairs ensure a uniform surface and prevent future

water infiltration.

• What is the main hazard when working with solvent-based

waterproof coatings?

• Noise
• Flammability and fumes
• Slipperiness
• Electrical shock

Rationale: Solvent-based coatings release flammable vapors and

toxic fumes requiring proper ventilation and PPE.

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