Old ways prove the best in fight to preserve ancient abbey

Medieval methods and materials are being used to put right a failed restoration programme at Fountains Abbey near Ripon.

A renovation at the Cistercian abbey in the Forties has done more harm than good and now nearly £100,000 is being spent to put things right.

In the process, diamonds are proving to be the thirteenth century abbey's best friend.

Skilled workers are using power tools tipped with industrial diamond drills to chip away at the rock-hard mortar which was used just after the Second World War.

The work is painstaking and labour-intensive, but is so authentic that the man heading the work says even the monks who built the abbey would recognise what was being done.

English Heritage is funding the major repairs on the abbey's magnificent south transept.

The World Heritage site is owned by the National Trust, but English Heritage is responsible for maintaining its fabric through a long-standing guardianship agreement. An investment of £350,000 is planned over the next three years alone and this repair job is part of that.

Masons wage a constant battle against erosion at the medieval masterpiece, but the latest project is tackling a problem with more modern origins.

The misguided repair scheme of the Forties by the Ministry of Works opted to use cement, mixed with granite fragments, to replace the crumbling mortar.

But instead of knitting the priceless stonework together, the twentieth century "wonder" material has led to accelerated erosion.

English Heritage consultant architect Peter Pace said: "Mortar not only keeps masonry in place, but it is also meant to absorb moisture from the surrounding stonework and take the brunt of weathering.

"But cement is exceptionally tough and not very porous and its use at Fountains Abbey has essentially reversed this process.

"As a result, the stonework has eroded much quicker, leaving the mortar standing proud."

To cure the problem, conservationists have tapped into the wisdom of the abbey's ancient builders and are replacing the cement with a medieval hydraulic lime mortar mix.

But before re-pointing can begin, the cement grouting has to be removed, a job which has proved to be extremely difficult.

"The only way to shift the cement is by using power tools tipped with industrial diamond drills," said Mr Pace. "Even then, it is taking a great deal of time to chip away.

"Fortunately, it seems no further damage is being caused to the stonework by this unusual work."

David Fraser, English Heritage regional director for Yorkshire, said: "Cement probably seemed the ideal material to use back in the Forties. But in this case it has proved to be totally counter-productive.

"It also underlines how far conservation techniques have advanced over the past few decades. We have a much better understanding of the mechanisms of erosion and perhaps an even greater admiration for the original builders of our great abbeys."

As scores of visitors gazed in admiration at the ruins of the old abbey, workmen were perched up to 60ft above them patiently tackling the hundreds of metres of cement grouting which has to come out.

One of the main aims of contract manager Henry Rumbold is that the public won't even know that anything has been done.

Mr Rumbold says that in parts of the abbey, the lime mortar is as good as the day it was first put in place 900 years ago. But the original sandstone has weathered and the cement is now standing out in places.

Craftsmen have been working on the project all summer. One man who digs out the cement pointing has to be replaced every so often because of the repetitive nature of the work.

On the south wall all the joints were filled with cement, which was harder than the stone and this was decaying, leaving the mortar exposed, to create holes through which water can run.

So the men drill a line of holes, chip the old filling out with mallets and chisels and then put the correct mortar in.

"It is as simple as that," said Mr Rumbold. "Eventually, even the correct stuff will weather. You can't stop it. But I want this to be so the public don't even know we have been here."

It was Peter Pace who spotted the potential problem a few years ago.

He says this work is very important for the long-term preservation of the stonework.

"We did not appreciate how strong the mortar was. This was a very strong mix," he said.

"I am sure the work was done in all innocence using technology and techniques which were modern at the time. They may have thought they were doing a better job than was done in the old days, but the knock-on effects were still to be realised.

"The old stone has to breathe and the materials they used don't allow for that."

So experts analysed what had been used to build the abbey, something no-one had done before.

"We worked out what was used to get the colour of the stone and what was needed to match the original as closely as possible," said Mr Pace.

"For old buildings it's usually best to use traditional techniques and you can't go far wrong. Modern additives leave you with uncertainty and the cost is tremendous if you get something like this wrong."

He stresses, though, that the Forties scheme was not a botch job.

"If it had not been for the repairs then we might not have a site at all now," he said.

"But we are going so far back to basics even the monks would recognise what the men are doing here today."