When should I replace cast iron pipes?
The most common type of cast iron rainwater pipe failure is a split in the back and the main reason for this is because a large number of rainwater pipes either touch the wall or the gap is very small, making it virtually impossible to maintain without removing it.
If there are blockages and water is trapped in the pipe this can freeze in winter months leading to the pipe splitting. When the warmer weather returns water can escape from the pipe potentially damaging your wall. It is therefore a good idea to undertake some type of maintenance in the autumn to clear away and leaves from your gutters and prevent them from falling into the pipes.
If your pipes remain structurally sound and no water is escaping from the rear then a simple annual inspection and clean should be sufficient. If there is any paint damage then this should be addressed by applying a metal primer prior to a top coat. If you can access the rear of your pipes with a paint brush then you have a much better chance of extending their life.
When a pipe is leaking it should be removed at the earliest opportunity to reduce the risk of structural damage to the property. It is occasionally possible to have cast iron rainwater pipe repaired and in the case of special or unique castings, this should be actively encouraged. For more common round profiles it is likely to be as cost effective to replace the defect piece with a new one.
Properly installed and maintained cast iron rainwater pipes can be expected to last in excess of 100 years so provided that you are able and willing to undertake the work the replacing of your cast iron rainwater pipe should at worst be a once in a lifetime experience.