Rain Gutter

A rain gutter is an open channel fixed along the lower edge of a roof to collect runoff and carry it to downspouts (downpipes), which take the water to the ground, a drain or a storage tank. Gutters protect walls, windows and foundations from saturation, reduce erosion around the building, and allow rainwater harvesting.

Regional names

Gutters go by many names: eavestrough in Canada, guttering in Britain, spouting in New Zealand, rhone or rone in Scotland and eaves-shoot in Ireland.

Profiles

• K-style (ogee or fascia style): a flat back and decorative curved front that resembles crown moulding; the dominant residential profile in North America. The ogee was also the standard Victorian gutter in Britain.
• Half-round: a semicircular trough, traditional in Europe and on older or heritage buildings, usually hung on brackets.
• Box gutter: a rectangular gutter, either fixed to the fascia or built into the roof structure behind a parapet or between roof slopes, as in M-shaped roofs. Concealed box gutters need a waterproof lining and generous overflow provisions because a blockage can send water into the building.
• Square-line and other profiles are also used.

Materials

Materials have included cast iron, asbestos cement, wood, copper, zinc, galvanised and stainless steel, aluminium and uPVC. In North America, seamless aluminium gutters roll-formed on site to the length of the run are common, avoiding joints.

Sizing and fall

Gutter size depends on roof area and local rainfall intensity. One rule of thumb cited for residential work is a 100 mm (4 in) gutter with a single 68 mm downpipe for about 56 m² (600 sq ft) of roof; codes and manufacturers provide detailed tables. Gutters are laid with a slight fall toward outlets; one British guideline gives a minimum of 1 in 360.

History

The Romans brought rainwater systems to Britain; the technology was later lost and reintroduced by the Normans.

Maintenance

Leaves and debris are the main cause of overflow. Gutter guards, regular cleaning, and adequate fixings to resist snow and ice loads all extend service life.