What role does felt play in a BUR system?

• A. Improves aesthetic appeal
• B. Provides insulation
• C. Provides stability and membrane reinforcement
• D. Acts as a drainage layer

Answer: (C)

In a Built-Up Roofing (BUR) system, felt primarily serves to provide stability and reinforcement for the membrane. The felt sheets are typically made of organic or fiberglass material and are layered between the asphalt in a BUR assembly. This layering helps distribute the load and adds structural integrity to the roofing system. The felt enhances the overall durability and flexibility of the roof, preventing issues such as cracking or buckling that could arise due to weather changes or thermal expansion.

While other roles like aesthetic appeal or insulation can be factors in roofing considerations, felt's primary function within a BUR is related to stability and reinforcing the membrane. Additionally, while a BUR system may involve drainage considerations, felt itself does not act as a drainage layer; rather, it is more integral to the roofing assembly's structural support.