downpipes

Downpipes are vertical pipes that convey rainwater from roof gutters down to a drainage system or watercourse. They are part of a building's rainwater drainage system and are commonly known as downspouts in North America. Downpipes connect at the gutter outlet and run along the building façade to ground level or into underground channels.

Materials vary by region and building; typical options include PVC (uPVC in the UK), aluminium, galvanised steel, copper, and cast iron. They come in various diameters and profiles, with round and square sections. Fittings such as bends, elbows, and branch connections are used to navigate corners and connect to underground drains. Brackets or straps secure the pipe to the wall at intervals.

Design considerations include ensuring sufficient slope for gravity drainage, typically a small downward slope along the length, and planning for overload during heavy rainfall. Blockages from leaves and debris are common; leaf guards or debris screens can be used at the gutter outlet but not always required on the downpipe. In cold climates, insulation or heating may be used to prevent freezing. Where rainwater harvesting is used, downpipes may feed into storage tanks via screening and valves.

Installation and maintenance: inspect connections for leaks, clean joints, check for rust or corrosion, and ensure clear outlets. Regular cleaning of gutters is advised as debris can fill the downpipe or overflow. Safety considerations include securing fixings and avoiding damage during high winds or ladders during cleaning.