Building Materials of Northamptonshire: Ironstone

April 9, 2021
by Sege Rosella
St Mary's Church Finedon
Ironstone house
St Mary's Church Finedon
Ironstone House
St Mary's Church Finedon
St Mary's Church Finedon
West End House
West End House

For the casual observer it’s easy to accuse Northamptonshire and her main towns such as Northampton, Kettering, Wellingborough and Daventry as giving very little to the world of architecture and construction.

There’s two reasons you might think this: most interactions with the county consist of travelling at high speed along the M1 or A14, and with their high grass banks flanking each side it’s easy to simply miss us as you go about your day.

The second reason is that the majority of the towns consist of post-war residential developments, which aren’t exactly the stuff of dreams. Yet, dig a little deeper and you’ll soon uncover some absolute gems, not only in the old centres, but also in the villages that are hidden amongst the green, rolling hills. In fact, the villages of Northamptonshire are some of the most picturesque in the country and feature a remarkable variety of incredible architecture and craftsmanship.

If there is one underlying trait to all the variety that we have it’s the quality and abundance of the local stone that builders have taken advantage of. Take this view of John Morton writing in The Natural History of Northamptonshire, 1712:

“And no County in England affording a greater Variety of Quarry-Stone than this, or exceeding this in the Goodness and Plenty of it, upon that account it deserves a more particular consideration.”

To be honest I was startled to find out that there are almost 40 different variations of stone in the county from the relatively unknown Desborough Stone to the more famous Collyweston Slate. As an interesting side note, the Collyweston slate mine was brought back into action at the end of January after a 40-year hiatus. This particular stone has been used in the construction of prestigious buildings such as Guildhall in London and Nuffield College, Oxford.

The Northampton Sand Formation is primarily concentrated in the central part of the county and it is responsible for producing three types of stone: Ironstone, Brown Sandstones and ‘Pendle’ Limestones and Dustin ‘slates’. My personal favourite are the Ironstones.

The county’s builders have used ironstone bricks in large quantities for hundreds of years, even so, it is incredibly difficult to find buildings that have been constructed with limestone bricks since 1850s.

You see, ironstone was dug for building-stone in small pits and quarries on local outcrops, but Northamptonshire became home to a massive iron-ore industry, which decimated these small pits and quarries before returning the land back to agriculture. As a result, it’s now incredibly difficult to buy this ironstone as it’s just no longer being quarried any longer. I did manage to find some being sold at a reclaim merchant and it’s safe to say they weren’t cheap.

Even so, there are examples of builders creating some lovely ironstone architecture. A notable example is the Church of St. Mary in Wellingborough, which was built in the early 20th century by the famous Gothic Revival architect, Sir Ninian Comper.

Personally, I love the aesthetic of ironstone. It has a much darker hue to sandstone - almost rusty. It actually has the appearance of being tough and hardwearing, which it actually is. The paradoxical thing about Northampton ironstone is that the process of weathering actually makes it more durable. Usually when we think of stone weathering we imagine the damaging corrosion of the type that can be seen in the photo of Tresham’s Market House (1578) in the centre of Rothwell. Ordinarily, when stone is weathered oxidation and hydration occurs on the surface of the stone and limonite is forms in the pore space. However, the pore space of Northampton ironstone gets filled with a form of limonite that is resistant to atmospheric decay. As a result of this durability there are lots of very well preserved buildings - mainly in Finedon and Wellingborough.