News: The Sustainability of Cast Iron and its use as a modern building material

15 April 2015

There is an old fashioned perception of iron foundries belching out smoke and fumes that probably dates back to the early industrial revolution. And whilst it is true we are energy intensive in our production, this does not tell the whole tale.

The properties of cast iron and its production may be better for the environment than is immediately obvious. Now we aren’t claiming to be saviours of the planet, we are after all melting iron and there is always a price to pay. However, this price can be offset by several factors.

Recycling Cast Iron

Cast iron can be recycled indefinitely without any decline in its properties. Everything we make at Hargreaves Foundry is recycled scrap iron. A mixture of used car parts, construction waste and foundry returns. We don’t use any ‘pig’iron at all. Foundries have always recycled scrap iron whenever possible, it is after all cheaper with no reduction in performance. It is important to stress that this is genuine recycling, not down cycling where products can be re-used but have inferior properties compared to their original usage.

Recycled Cast Iron and Steel

Longevity and Value

Another way in which cast iron can offset its production ‘costs’ is its longevity and value. Cast iron products are legendary for their durability and long life. Never mind a ten year builders’ guarantee, properly maintained cast iron products will last the life of a building. Research has shown that the whole life costs of cast iron over a 100 year life cycle are only 35% of aluminium or PVC, despite a higher capital cost. The report demonstrates that cast iron has a significantly lower impact in terms of energy consumption and CO2 emissions than PVC and aluminium. Not only that, but when the building has served its purpose and is eventually demolished the cast iron can be recycled and used again for exactly the same purpose.

Still relevant in the 21st century

Cast iron has long been used in the construction industry for a variety of products ranging from structural support, windows, roof lights, rainwater and soil drainage, decorative features and others. It has immense compressive strength but low tensile strength. It can be moulded into complex and detailed designs. It was especially popular during the Victorian and Edwardian periods and features strongly in our nation’s built heritage. However, it still has a place today as demonstrated at One Pancras Square, designed by David Chipperfield Associates and featuring 396 cast iron columns with a basket weave design manufactured here at Hargreaves Foundry. Aesthetic considerations apart, it is indeed a beautiful and award winning building, One Pancras Square also achieved a BREEAM rating of outstanding with a score of 89.3%, which further demonstrates the contribution of cast iron to the sustainable credentials of a well designed building.


One Pancras Square – BREEAM rating Outstsanding


Iron is the fourth most common element in the earth’s crust, and can be fully recycled to produce products of equal integrity to the product it has been recycled from. This makes it a very sustainable material.

Our production process is energy intensive but this can be offset by the durability and longevity of cast iron products which will serve the life of a building and can still be recycled after the building has gone.

These properties, combined with other elements in a well designed, modern building can help achieve the highest environmental ratings.


To talk about your project, contact Andy Knight, Foundry Manager Tel: 01422 399111 Contact us via Linkedin or Twitter or speak to Andy on Twitter.