One of the most useful improvements in house construction in recent years has been the widespread use of plastic gutters and downpipes, which need virtually no maintenance or decoration and which are easy to install and remove. Their predecessors, mainly cast iron, can corrode away, and once cracked or broken can be difficult to repair. An inspection of your rainwater system will tell you what state of repair it is in.
At least once a year, climb up to eaves level with a trowel and bucket, and remove debris where it has collected; then take your garden hose up on the next trip and swill the whole system out thoroughly. Hose downpipes through to clear any debris that you may have allowed to fall down them while cleaning the gutters.
Repairing rainwater systems
You may find that sections of gutter have sagged because the fixings are inadequate, or because joints between lengths or components have come adrift. Sagging sections will accumulate debris, and will usually have water standing in them. With a plastic system, it will be comparatively simple to unclip the offending section, reposition the fixing brackets to restore the correct slope and clip the gutter back into place. But if you have a cast iron system you may have bigger problems. You can repair leaking joints with bituminous mastic or flashing tape, and you may be able to patch cracks or missing pieces in gutter sections in this way too. Leaks in downpipes are more difficult to repair, and you may have to dismantle
the entire run to patch them. Broken and sagging gutter brackets must be replaced, and unless you want to take down the entire run you will have to use brackets that screw to the fascia board rather than the rafter ends. To position them you will have to wedge up the gutter somewhat by carefully driving strong nails into the fascia.
If you are taking down cast iron guttering, be warned: it is extremely heavy, and you should not attempt the job on your own.
Downpipes are secured by nails driven through lugs at the top of each length into the masonry, or into wooden plugs. Refix them if necessary using masonry nails fitted with retaining washers. At the bottom end of each downpipe, make sure that the shoe is undamaged and is discharging water into the gully; if it is not, you may get damp.
Putting up a new rainwater system
Modern plastic guttering systems offer a range of components that allow you to cope with every eventuality. Joints are usually made by clipping the cut ends of the gutter sections into unions containing neoprene gaskets for a waterproof join. Simple brackets support the gutters, and these must be set along the fascia to give the guttering run a slight fall towards each downpipe — a drop of about 25mm (1n) on a 3m (loft) run. A length of string is used to align the brackets along the run, and these are then screwed into place at m (3ft) intervals.
Where the gutter parts join, you must allow an expansion gap of about 12mm (1/2in) at the union. With the guttering run completed you can put up the downpipes, fixing them at roughly 2m (6ft) intervals with clips and checking with a spirit level or plumb line that the run is vertical. A swan neck allows the pipe to reach the gutter outlet where the eaves overhang, while a shoe at the lower end discharges water into an open gully. If you are having to dig a soakaway to take water from new downpipes, take the opportunity to install a better closed back-inlet gully.