Overflow scupper and weir systems — box gutters

Blucher (part of the ACO Group) manufactures a range of stainless steel drainage products including wall-mounted overflow scuppers for box gutter overflow compliance. The Blucher overflow scupper is a stainless steel outlet body installed through the gutter wall or parapet at a set height above the primary drainage outlet — when the primary outlet is blocked or overwhelmed and water rises to the overflow scupper invert level, water discharges through the scupper and away from the building structure. The adjustable height feature allows the specifier to set the scupper invert at the required level above the primary outlet to comply with NCC performance requirements for overflow provision. Stainless steel construction provides long-term corrosion resistance appropriate for both coastal and inland environments. Blucher overflow scuppers are compatible with the Blucher primary outlet and drainage channel range, simplifying specification on projects where a single manufacturer's drainage system is preferred. Confirm the required scupper size, flow capacity, and positioning with the hydraulic engineer before ordering. NCC overflow requirements for box gutters in Class 2 buildings are mandatory — the overflow system must be designed and documented by a licensed hydraulic engineer.

Geberit is a major European plumbing and drainage manufacturer with Australian operations. Geberit's overflow outlet range includes products suitable for box gutter secondary overflow compliance, available in stainless steel and plastic variants depending on the application and budget. The Geberit overflow outlet is typically a through-wall fitting installed in the gutter wall or parapet at the required overflow height. Stainless steel variants are preferred in exposed or coastal environments. Plastic variants are suitable for concealed or protected applications where material compatibility with the gutter lining has been confirmed. Geberit overflow products are commonly used in conjunction with Geberit primary drainage systems on larger commercial and strata building projects. Confirm the required overflow type, size, flow capacity, and material with the hydraulic engineer before selecting the appropriate Geberit product from their range. Geberit technical support can assist with product selection and hydraulic sizing data.

Alproc Fabrication supplies pre-fabricated aluminium weir overflow systems for box gutter overflow compliance. Unlike a scupper (which is a through-wall outlet fitting), a weir overflow is a threshold device — a low-profile barrier set at the required overflow height within or at the gutter wall that allows water to overflow harmlessly to the outside of the building when the primary drainage is blocked or overwhelmed. The Alproc pre-fabricated aluminium weir is supplied to a specified flow rate, allowing the hydraulic engineer to confirm that the weir provides sufficient overflow capacity for the catchment area under the NCC design storm. Aluminium construction provides good corrosion resistance and low weight — it is compatible with aluminium and Colorbond box gutter linings but must not be installed in contact with copper elements without isolation. Alproc can fabricate weir overflows to custom dimensions and flow rates where standard products do not satisfy the hydraulic design. Confirm the required weir height, length, material, and flow rate with the hydraulic engineer before ordering.