Gutters and Downspouts:
Scuppers

Description: Scuppers are used to provide an outlet through parapet walls or gravel stops on flat and built-up roofs to allow drainage of excess water. They can be used in conjunction with gutters and downspouts to divert the flow to the desired location.

Scuppers can be installed to carry water into gutters or directly into downspouts through conductor heads. When a conductor head is used, it should be at least 2" wider than the scupper. When neither conductor heads nor gutters are used to catch the water, scupper spouts should extend past the exterior surface of the building to avoid wetting the building surface.

The minimum recommended weight for the construction of scuppers is 16 oz. copper. Scuppers are fabricated with flanges on the roof side which extend 4" onto the roof. Wood blocking is required under scuppers to provide a nailable surface. Scuppers should be spaced no greater than 10 feet apart depending on the roof area drained.

Special Conditions: In areas with severe ice and snow conditions and/or excessive debris, conductor heads with overflow openings should be used.

Where a roof is completely surrounded by parapet walls and drainage is provided by scuppers or internal drains, overflow scuppers should be provided.

The roof-side flange of the gravel stop is nailed at 3" O.C. to the perimeter blocking.

A. Scupper at Raised Roof Curb This detail illustrates the installation of a scupper through a raised roof curb with a gravel stop. Since no gutters or conductor heads are provided, the scupper spout should extend beyond the exterior face of the building.

All joints of the scupper should be soldered. The edge of the copper fascia and gravel stop at the scupper should also be soldered.

B. Scupper at Gutter This detail shows a scupper used in conjunction with a gutter. The scupper spout is soldered into the copper fascia and gravel stop.

The drip edge of the fascia should extend over the back edge of the gutter by 1" minimum. The scupper and gravel stop flanges are nailed to the blocking. The gutter should be allowed to move independently of the fascia/gravel stop.

C. Scupper at Conductor Head The conductor head must be at least 2" wider than the scupper. It is attached to the wood nailer through the fascia. The scupper spout is locked and soldered to the conductor head. All joints between scupper, conductor head, downspout, fascia and gravel stop are soldered.

The minimum weight of copper suitable for conductor heads is 16 oz.

D. Scupper at Parapet Wall Shown is the install-ation of a copper scupper through a parapet wall in conjunction with conductor head and downspout.

The conductor head is attached to the exterior wall using masonry fasteners. The scupper spout is locked and soldered onto the back edge of the conductor head. If conductor heads without overflow are used, the rim of the head should be set 1" below the scupper.

A closure flange is inserted and sealed into a masonry joint above the scupper. The sides are also sealed against the masonry. The scupper is locked and soldered onto the flange at the top and two sides.

On the roof side, the flange is covered by copper flashing. The flange is formed and soldered to the roof side of the scupper, leaving at least 4" of material around the opening. A continuous sheet of copper counterflashing is inserted into a masonry joint above this flange. This flashing extends at least 2" beyond the ends of the flange and laps the soldered joint between the flange and the scupper.

The bottom edge of the scupper on the roof side is locked and soldered into a continuous copper cleat. A copper gravel stop is soldered in the scupper.

E. Overflow Scupper This detail illustrates the installation of an overflow scupper. Overflow scuppers should be carefully positioned to prevent excess water from remaining on the roof if the regular scuppers become clogged. They should, therefore, be placed at an elevation higher than the regular scuppers.

The outside detail is similar to Detail D, except that conductor heads and downspouts are not required. The scupper is locked and soldered to the closure flange on all sides.

On the roof side, overflow scuppers can be detailed similar to Detail D. The detail shows an alternate method of constructing either type of scupper. The top of the roof side flange is extended into a masonry joint. The sides of the flange are sealed against the masonry.