Installer Low-Slope Exam Practice

NRCA ProCertification Roof System Installer Low-Slope Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary purpose of a low-slope roof system?
• To enhance aesthetic appeal
• To prevent water infiltration
• To support heavy snow loads
• To increase insulation

Rationale: Low-slope roofs are designed primarily to shed water efficiently

and prevent leaks, not for aesthetic purposes or heavy loads.

• Which of the following materials is most commonly used as a vapor

barrier in low-slope roof systems? 1 / 4

• Fiberglass insulation
• Polyethylene sheet
• Asphalt shingle
• Metal decking

Rationale: Polyethylene sheets are commonly used as vapor retarders to

prevent moisture from entering the roofing system.

• What is the typical maximum slope for a roof to be classified as low-

slope?

A. 4:12

B. 3:12

C. 2:12

D. 1:12

Rationale: Low-slope roofs are generally defined as those with slopes of 2:12 or less.

• Which insulation type is most commonly used in mechanically

attached low-slope roofing systems?

• Fiberglass batts
• Polyisocyanurate (ISO) boards
• Cellulose
• Spray foam 2 / 4

Rationale: Polyisocyanurate boards are widely used due to their high R-value

and compatibility with mechanically attached systems.

• What is the purpose of a cant strip at the intersection of a roof deck

and a parapet wall?

• Decorative trim
• To create a smooth transition and reduce stress on the membrane
• To support roofing insulation
• To act as a water diverter

Rationale: Cant strips reduce sharp angles, minimizing stress and potential

membrane damage at wall-to-deck transitions.

• Which type of flashing is recommended for low-slope roof

penetrations?

• Roof-to-wall flashing
• Prefabricated or field-fabricated flashing
• Aluminum drip edge
• None of the above

Rationale: Flashing around penetrations must be watertight and durable;

prefabricated or properly field-fabricated flashings are standard.

• / 4

• In a fully adhered membrane system, how is the membrane secured?
• By nails only
• By adhesive applied to the substrate
• By gravity
• By mechanical fasteners only

Rationale: Fully adhered systems use adhesives to attach the membrane

directly to the substrate, providing uniform contact and waterproofing.

• What is the minimum recommended slope for positive drainage on a

low-slope roof?

• 1/4 inch per foot
• 1/2 inch per foot
• 1/8 inch per foot
• 1 inch per foot

Rationale: A minimum slope of 1/8 inch per foot is recommended to ensure

water drains properly and prevents ponding.

• Which roofing system is classified as a “single-ply” membrane?
• Built-up roof (BUR)
• EPDM, TPO, or PVC
• Modified bitumen
• Asphalt shingle
• / 4