Most old houses have cast iron gutters and downpipes. They are very long lasting if painted
regularly. The insides should be primed with zinc chromate paint. The finishing coat should
be a bituminous paint. They are heavy and their fastenings should be maintained and checked
at regular intervals. Today other materials are used in place of cast iron.
UPVC gutters
PVC gutters are made from unplasticized polyvinyl chloride. The sections and fittings are
lighter, easy to fix and do not require painting. The fittings available are the most common
used and easy to work with if fitting them as a DIY enthusiast. Half round, square and ogee
profile guttering and fittings are available. An ogee is a half-round adaptor used to join
gutters of different profiles. Square gutters have a much greater capacity for carrying water
than the half-round type. If you need to replace part of the cast iron gutter, there are
adaptors available to connect new PVC guttering to either half round or square cast iron
guttering. It is important to replace any guttering with a type using a similar size channel.
When the first guttering was installed, its size was calculated to deal with the amount of
water likely to come off the roof during a period of heavy rain. If you choose a smaller
channel of gutter, you could experience overflowing water damage at times of heavy rain.
Larger channels are not a problem, but will be extra unnecessary cost. It is sensible to get
a list or brochure showing the entire set of fittings available from a manufacturer before
starting to buy parts.
Most domestic rainwater installations use 100mm (4 inch) gutter widths
and 62.5mm (2½ inch) downpipes. There should be a slight slope on the guttering leading to
the downpipes. A 1 in 600 slope is ideal for guttering, measured from the base of the facia
boards.
Pressed steel gutters
Pressed steel gutters are lighter and stronger than cast iron ones. They usually come
galvanised or primed ready for painting.
Vitreous enamelled gutters
Vitreous enamelled gutters come in a variety of colours. The downpipes are available in the
same range of colours.
Asbestos gutters
Asbestos gutters are also available. They do not have to be painted and are easy to fix. This
type of guttering can become brittle with age.
