Research Looking To Bring Unique Collyweston Slate Back To Life

Britain is full of distinctive building styles, from the rich honey coloured stone of The Cotswolds to the wide ranging use of flint in East Anglia. Although increasingly expensive to use, they are still readily available if required to comply with strict planning requirements.

Collyweston Slate Could Make A Comeback

One such building material that has virtually died out because of financial constraints on its availability is Collyweston Slate. To be found on rooftops in historic villages, churches and stately homes, Collyweston slate has helped define the look of some of England's most well-loved traditional buildings.

It first appeared as a building material in the Northamptonshire village of Collyweston centuries ago, hence the name, and the mining for the slate throughout the East of England really hit its popular peak in the late 1800s.

However, like many such specialised building materials, it rather hit the buffers in the 1970s, with extraction of the distinctive limestone becoming commercially unviable.
Now English Heritage, together with other partners,  are looking into research to find out whether mining could become commonplace once again, by seeing if they can speed up the timely process of the rock being ready for the roof.

"We've been testing for about a year and we're trying to get the process of the stone being prepared for roofing from three years to within a few weeks," said Chris Wood, head of buildings conservation and research at English Heritage.

"We have got a lot more work to do - this is essentially only testing and trying to get the method right.  It was very successful in the lab, but to do it on a basis where it might be commercially attractive is a lot more work."

Time that nature takes appears to be an important part of the battleground. To get the stone prepared, Mr Wood pointed out that it normally needs to be left outside for three winters until the frost revealed layers that could be broken into perfectly flat slates. But even nature can be manipulated it appears, as it has been discovered that by dousing the rock in water and then putting it in a large freezer, tests have revealed that the natural freeze-thaw process can be moved along pretty quickly.

"It has tremendous potential to be commercially viable again and we're confident the process can be refined," said Mr Wood. "There is huge demand for the slate because it's a unique stone and there is potentially a big market to tap into.

"There are hundreds of buildings around Northamptonshire, Lincolnshire, Cambridgeshire and even in London and east Yorkshire that still have the slate on them. But because supply is so low, it's made it expensive and many old unlisted buildings are being stripped of Collyweston which is harming the historic environment."

It seems as though there is a general will for the slate to be used again, so that new buildings can be made to blend with old.

"We want to maintain the distinctiveness of roofscapes in historic areas and there's an impetus to reduce the loss of materials from unprotected buildings," said Mr Wood.

"It's a highly sustainable and green industry and hopefully an active market can start once again with apprentices learning new skills and rural areas having greater employment prospects".