Alumasc Rainwater – Protecting your cast iron guttering

Cast iron is a popular and well-used material for rainwater guttering on many UK building projects. Tough, strong and 100% recyclable, cast iron can last in excess of 100 years, if properly manufactured, protected and installed. But if exposed to the elements without the proper protection, cast iron will fail.

The key to ensuring longevity of your cast iron rainwater system is paint, but only paint which has been properly applied, and with enough coats. Primed systems for painting on site have long been specified with a view that they are the most cost effective. But Alumasc Rainwater has changed that.

Alumasc’s pre-painted cast iron is only 13% more expensive than primed cast iron, but the long-term cost savings far outweigh this modest initial investment.

Alumasc’s Apex Heritage cast iron rainwater lasts up to 10 years before it needs repainting. The painted guttering goes through a four coat system, using certified paint which is factory-applied under strictly controlled conditions. The paint, which is available in 8 standard heritage colours, has been specifically developed to give a smooth and long lasting finish to the cast iron – this is extremely difficult to replicate on-site.

Furthermore, care has to be taken to ensure that all surfaces are fully and evenly painted, otherwise rust will set in and weaknesses will be exposed putting at risk the entire guttering system and the fabric of the building it protects. It’s worth remembering that rainwater guttering is there to protect your property. If it fails to perform and water starts to attack the building the cost of putting that right is out of all proportion to the small initial investment in cast iron protection.

Fully factory painted cast iron may need a touch-up in 5-6 years to maintain the protection. This means lower materials and labour costs over the lifetime of the project.

To verify the facts and put industry minds at rest, Alumasc Rainwater have recently commissioned a series of independent 1000-hour salt-spray tests to confirm the performance of their pre-painted cast iron range. These tests were performed on Alumasc’s factory certified painted finish, on that of an inferior paint finish applied on site (i.e. NOT an equivalent four-coat finish) and also on the painted finish of the competition.

The results of the tests will be published in a Technical White Paper, which will be available to download from the Alumasc Rainwater website in early 2015.

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