Final answer:
Ventilation for flat roofs is typically achieved through roof vents designed for flat or low-slope roofs, mechanical ventilators, and sometimes skylights, rather than ridge vents, dormer windows, or gable vents.
Step-by-step explanation:
When ventilating flat roofs, the most common openings are not ridge vents, dormer windows, or gable vents, which are typically found on pitched roofs. Instead, flat roofs often utilize different methods for ventilation to prevent moisture buildup and to control the temperature. The most common ventilation methods for flat roofs include roof vents specifically designed for flat or low-slope roofs, mechanical ventilators, and, in some cases, skylights that can open to allow air circulation.