Romancing the stone (From Free Press Series)

Romancing the stone

For several years the south aisle of Tintern Abbey has been obscured by a network of scaffolding while a team of stone masons has been repairing and conserving the twelve ornate tracery windows.

The project has involved expertly crafting and shaping more than 90 pieces of new stone (some weighing several hundredweight) to replace badly eroded original mouldings. Many hundreds more have been painstakingly repaired and consolidated.

With the historic windows now 'unveiled', thousands of first-time visitors to the Abbey will pay the stone masons the best possible compliment by not even noticing where the original stone is married to the new.

The works, managed by John Shipton and led by Alan Cornish, was the first phase of a 10-year conservation programme at the Abbey planned by Cadwraeth Cymru, the works arm of Cadw.

Alan Cornish, from Walterstone near Hereford, who has been a stonemason for nearly thirty years, says restoring the tracery windows was one of the most challenging and intricate tasks he has ever undertaken.

"Before the work on site even began a geological survey was commissioned to find the closest match to the original sandstone, which almost certainly came from local quarries. The best match turned out to be from the Hollington quarry in Staffordshire.

"On this project, as on any other, my first job was supervising construction of the scaffolding. After that, working with a colleague, I used a tape measure and a large compass on a stick to take measurements. The aim was to get within one eighth of an inch of accuracy for the points between the stones.

"Each window in the south aisle has eleven tracery stones and six cusps. Exposure to the elements had reduced some sections to half their original diameter.

"We needed to replace one window in its entirety and repair the rest in sections. We also carried out lime mortar repairs on the existing stonework and strengthened some sections by injecting them with resin.

"Working from detailed drawings I began by making a full-scale drawing on cardboard, including all the discrepancies. Then I cut zinc templates from the drawings which were used to mark the stone for 'dressing'.

"The 'dressing' phase involves using a grinder to remove the waste, then steel and tungsten-tipped chisels. One stone could take ten days' work.

"The completed section was transferred by trolley to the foot of the scaffolding and hauled up 60ft with pulleys. For safety reasons we had to brace the whole window - even for small repairs.

"Fixing the pieces in place was harder than dressing the stone. The masons who built the abbey had no structure above them whereas the stones we dressed had to be pushed into the existing wall.

"While I was working I was aware of the short-cuts that had been taken by the stonemason who made the original windows. Everyone's hand is different. I'd notice, for instance, where he had put in small pieces and dressed them to shape after fitting. Crafty so-and-so I'd think - if I did that I'd be lynched.

"Stone masonry is a tough, physical job at the best of times and even harder when you're working on the top of a building in mid-winter in the wind and rain!

"Most school leavers today would rather become IT consultants or work in the media. But personally I find it very interesting to be re-creating something that was designed many centuries ago, knowing that the work we're doing will last just as long."

Mial Watkins, national manager of Cadwraeth Cymru, described the restoration work carried out by Alan and his team as 'superb' and 'a testament to their skills'.

The next major project at the Abbey - restoring the Monks Refectory - would present a new set of challenges.

"Some stone replacement was essential in the south aisle for structural reasons, whereas in the Refectory we will be trying to conserve as much of the eroding stonework in the mouldings and carvings as possible.

"This will mean extending the 'palette' with techniques such as resin repairs, soft mortar repairs and stainless steel pinnings. It's a bit like dental work - arresting the decay with bridges and fillings.

"After that we hope to take on the toughest challenge of all - a major programme of conservation and repair to the Abbey's famous West Front."

The new church at Tintern Abbey was started in 1269 and was not finished until the early years of the 14th century. For the monks to build on such a grand scale they needed the patronage of Roger Bidgod, fifth earl of Norfolk and lord of Chepstow Castle.

He helped to ensure that the design of the building was in the most up-to-date style, drawing upon the details pioneered at Westminster Abbey and old St Pauls Cathedral in London.

The tracery windows provide the drama and interest in the abbey church. Their style develops from Geometric at the east end to Decorated at the west end, suggesting that two master masons may have been involved.

Cadw's masons have worked very hard to replicate exactly the geometry and subtle details of each window to carry forward what was almost the signature of their predecessors of over 700 years ago.