Parapet Roof Drainage Design

Looking at a building from the ground a parapet may seem to simply be a design choice that adds little more than a characteristic look to a building.

Parapet roof drainage design.

This would be in situations where a retaining wall or parapet prevents direct access to the roof s edge. On larger and more complex schemes specialist consultants may be employed to design the rainwater drainage system. Install a drain at most 50 ft. Buildings that incorporate flat roofs with centralized roof drains and internal downspouts are another story.

The drainage requirements for flat roofs on buildings present some special problems that we describe and illustrate here. This kind of drainage system is most common on small flat roofs where water volume and buildup isn t extreme. However parapets block the drainage of rainwater from freely flowing over the roof edge. Working with manufacturers will help develop your understanding but don t delegate your design responsibility to them.

This type of pattern is particularly useful on buildings that are easily divided into rectangular areas. From a roof edge. Limit the number of parapet walls. With a parapet wall it is possible for a roof to retain or pond water should the primary roof drainage system fail.

The premise of the pattern is that a drain is positioned in the center of the rectangular area and there is a four way positive slope into the drain. From the edge of a valley. If a building has roof access that residents use regularly for whatever reason adding a parapet greatly decreases the chance that someone could fall over the. Adding a parapet wall makes a flat roof far safer than leaving the roof s edge exposed.

In these cases the. Keep the distance between drains to at most 200 ft. Architectural home design software all content support videos chieftalk forum. Roofs of this design will have one or more roof drains or scuppers installed.

Watch for clogs blockage at the roof drain or scupper. At page top and at left our photos show a low slope roof surrounded by a parapet. It s also sometimes used in tandem with scuppers. Requires a primary drainage system with.

Parapet and valley gutters are treated differently because they have a higher risk of failure. Provide adequate flashing for parapets openings walls joints skylights etc. The most dependable type of roof drainage design is the inverted pyramid pattern. Manually adjust roof planes to have a negative pitch to create a parapet wall structure with a center drain.

Typically surrounded with parapet walls to screen roof top equipment and to provide. Install a drain at most 50 ft.