What is commonly used to ensure proper drainage on a roof with HVAC installations?

A sloped roof design is commonly utilized to ensure proper drainage on a roof with HVAC installations. This design facilitates the effective flow of water away from the roof surface and prevents the accumulation of water, which can lead to issues such as leaks, mold growth, and structural damage over time.

By incorporating a slope, gravity aids in directing rainwater toward designated drainage points, such as gutters or downspouts. This is particularly important in roofs that support heavy equipment like HVAC units, as the added weight can exacerbate drainage problems if water pools around these systems.

Other options present configurations that may not be as effective in promoting proper drainage. For instance, while gravel can sometimes assist with drainage, it is not a structural solution and does not replace the need for sloping. Pitched guttering can help manage drainage but does not directly address the roof's overall slope. Flat roof designs, although popular for various reasons, often require additional drainage solutions like internal drains or scuppers to effectively manage water, as they are more prone to pooling without a proper slope.