A flat roof with a parapet must slope toward what feature for proper drainage?

A flat roof with a parapet must slope toward roof drains to ensure proper drainage. When designing a flat roof, it's essential to manage water runoff effectively to prevent pooling and potential water damage. Roof drains are strategically placed in low areas of the roof where water naturally flows, facilitating efficient drainage.

By sloping the roof towards the drains, the design encourages water to flow directly into these drains, minimizing the risk of water accumulation. This is especially important on flat roofs, where a lack of slope can lead to standing water, creating issues with structural integrity, roofing materials, and potential leaks.

While edges, walls, and gutters can be involved in the overall drainage system of a building, they do not serve as direct points for drainage like roof drains do. Edges might lead to overflow situations without proper collection points, walls can obstruct water flow, and while gutters can help manage drainage from parapets, they don't serve the primary purpose of directing water off the flat roof itself. Thus, sloping toward roof drains is the optimal choice for maintaining the roof's integrity and ensuring effective drainage.