Final answer:
The types of insulation used for flat roofs are urethane, fiberglass, and polystyrene. These materials are chosen for their ability to trap air and reduce heat conductivity, serving as effective insulators.
Step-by-step explanation:
The types of insulation used with a flat roof include urethane, fiberglass, and polystyrene. These materials are chosen for their insulating properties, which involve the trapping of air in small pockets, as air is a poor conductor of heat, according to Table 1.5. Urethane, as detailed in the reference, is used in many applications due to its durability and insulating qualities, making it suitable for rigid foam insulation panels. Fiberglass is also a common insulator for walls and ceilings as it prevents heat transfer between the building's interior and exterior environments, per Figures 1.23 and 14.16. Polystyrene is mentioned as a very poor conductor and thus an effective insulator ideal for insulation purposes.