What can be constructed between the roof sheathing and the air-impermeable insulation using the Combination Method?

The correct answer illustrates that a ventilation space can be constructed between the roof sheathing and the air-impermeable insulation using the Combination Method. This design choice is crucial in managing moisture and air movement within building assemblies.

When insulation is installed against roof sheathing, there is a risk of condensation forming if warm, moist air from the living space reaches the cold sheathing. By incorporating a ventilation space, you create an avenue for air to flow, which helps to remove moisture-laden air before it can condense on the sheathing. This is particularly important in roofing systems to maintain structural integrity and to prevent issues like mold and rot, which can result from trapped moisture.

In the context of the other options, while a moisture barrier is essential in some applications, it does not specifically address the airflow needed for moisture control in this scenario. An insulation blanket refers to a type of insulation but does not pertain to the space or method of moisture control detailed in the question. Similarly, a safety platform is unrelated to insulation or moisture management; it is typically used for construction safety rather than thermal or moisture performance in building assemblies. Thus, the ventilation space is the most effective strategy to achieve the necessary moisture management in the given construction setup.