Installer Modified Bitumen Exam Practice

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

• What is the primary function of a modified bitumen roof system?
• Aesthetic enhancement
• Waterproofing and weather protection
• Thermal insulation
• Structural support

Rationale: Modified bitumen roof systems are designed to provide a

waterproof barrier and protect the building from weather elements.

• Which modifier is commonly used in modified bitumen membranes?
• Polyurethane
• Polyester 1 / 4

• Atactic polypropylene (APP) or styrene-butadiene-styrene (SBS)
• Epoxy

Rationale: APP and SBS are the two primary modifiers used to enhance

flexibility and durability in modified bitumen membranes.

• Which type of modified bitumen membrane is torch-applied?
• Self-adhered
• Cold-applied

C. APP

D. SBS

Rationale: APP membranes are typically torch-applied to create a strong

bond with the substrate.

• SBS-modified bitumen membranes are characterized by which

property?

• Rigid at low temperatures
• Flexible at low temperatures
• Cannot be cold-applied
• Only used on steep slopes

Rationale: SBS modification provides rubber-like flexibility, making it

suitable for colder climates.

• Which layer is typically installed directly over the roof deck in a

modified bitumen system?

• Cap sheet 2 / 4

• Base sheet
• Underlayment or base sheet
• Gravel surfacing

Rationale: The base sheet provides a smooth, stable surface and initial

waterproofing layer for the roof system.

• What is the purpose of granules on a modified bitumen cap sheet?
• Increase flexibility
• Protect from UV degradation
• Improve adhesion
• Facilitate water drainage

Rationale: Mineral granules protect the asphalt surface from ultraviolet

rays and enhance durability.

• What type of insulation is commonly used under modified bitumen

systems?

• Fiberglass batts
• Spray foam only
• Polyisocyanurate (ISO) or extruded polystyrene (XPS)
• None, insulation is not required

Rationale: Polyisocyanurate and XPS are commonly specified due to high

compressive strength and moisture resistance.

• What is the minimum recommended slope for a modified bitumen

roof system? 3 / 4

• 0%
• 1/4 inch per foot
• 1 inch per foot
• 2 inches per foot

Rationale: Modified bitumen systems perform best with low slopes of at

least 1/4 inch per foot to ensure proper drainage.

• Which is a common method for adhering self-adhered modified

bitumen membranes?

• Torching
• Hot asphalt
• Peel-and-stick adhesive
• Mechanical fasteners only

Rationale: Self-adhered membranes rely on a factory-applied adhesive to

bond to the substrate without heat.

• What safety equipment is essential when torching APP

membranes?

• Gloves only
• Fire extinguisher, gloves, and eye protection
• Hard hat only
• None

Rationale: Torch applications present a fire hazard; proper PPE and fire

safety equipment are mandatory.

• / 4