Gutter

A vertical pipe conveying rainwater from a roof outlet or gutter down to the drainage system at ground level. Downpipes are made from cast iron, steel, aluminium or plastics, and their number and size are determined by roof catchment area and design rainfall intensity.

The drainage fitting through which water leaves a flat roof or gutter into the downpipe system, incorporating a clamped or welded connection to the waterproofing and usually a leaf guard or grating. Outlets are positioned at the low points of the falls, with secondary overflow provision to guard against blockage.

The lower horizontal edge of a roof slope, usually projecting beyond the wall face, where rainwater is discharged into the gutter. Eaves details typically include the fascia, soffit, ventilation openings and underlay support to prevent water being trapped behind the gutter.

The designed slope built into a nominally flat roof so that rainwater drains towards gutters or outlets. Falls may be formed by the structure, screeds, firring pieces or tapered insulation, and design gradients are normally set steeper than the minimum finished fall to allow for construction tolerances and deflection.