Extreme weather warning: Britain's heritage buildings feel the heat – and cold

Experts fear they are fighting a losing battle as increasingly erratic conditions take their toll

The curators responsible for preserving Britain's historic sites already have to cope with falling subsidies and the effect of the economic gloom on visitor numbers. Now they have another problem: our increasingly extreme and erratic weather.

Freezing temperatures, drought and torrential rain are all proving increasingly damaging to sites that, in some cases, are almost 1,000 years old.

Earlier this month, parts of the roof of St John the Baptist Church in Woodhurst, Cambridgeshire, collapsed, with masonry falling from the chancel, causing damage that will cost up to £40,000 to repair.

Experts said the problems were caused by the drought's effect on soil that is found particularly in the east of England. The trees close to the walls of the Grade II-listed building sucked up too much water from the ground after two years of low rainfall, causing the clay to contract. This moved the foundations, and the walls cracked.

Ian Harper, an architect with English Heritage said: "The problems with the drought's effect on the clay have emerged recently and we haven't worked out how to prevent it."

Finding funding for the necessary repairs is becoming increasingly difficult. "Every year we have a grants programme and every year there are about twice the applications we can fund. This is becoming more of a problem. It has been developing over the past 10 years," he said.

Other churches have been affected in similar fashion. St Mary's, in the village of Mundon, Essex, had to undergo significant repairs as a result of clay shrinkage, which led the building's foundations to start "falling apart". The restoration work, following a £140,000 grant from English Heritage, averted the collapse of the chancel and preserved its Georgian murals.

In the Church of St Andrew, at Abbots Ripton, also in Cambridgeshire, the arcades were found to be moving on the foundations, causing cracks. Without repair work, it is likely that the whole building will collapse, Mr Harper said.

St Andrew's Church at nearby Wood Walton, which was recorded in the Domesday Book, is also facing serious problems. "We think it is due to the climate. It may be just two or three years aberration, but the climate has definitely had an impact," Mr Harper said. Two years ago the building was put on the Heritage At Risk register and no longer opens regularly.

The most recent Heritage At Risk register was published in August. There were 5,828 entries, with 3 per cent of Grade I and II-listed buildings deemed to be threatened. Although the effect of increasingly extreme weather is difficult to quantify, many list erosion and weathering as a problem. English Heritage says its budgets have been "significantly reduced" due to Government spending cuts.

While drought has become an issue in some parts of the country, the cold winters of 2009 and 2010 also caused serious problems at several sites, including Castle Acre Priory in Norfolk, a monastic site dating back to 1090, and the 12th century Framlingham Castle in Suffolk.

Mr Harper said: "The frost is a real issue. In the past two severe winters, hard frost caused huge damage to standing ruins in the east of England. The chalk in the stonework deteriorates. We understand the process and know we can't stop it."

In Norwich, the medieval city walls have suffered damage as a result of the salt used on the roads in cold weather.

The National Trust has also pointed to a rise in threats from extreme weather – specifically torrential rainfall.

Sarah Staniforth, museums and collections director for the organisation, said: "The weather is much more extreme in the UK than it used to be. Between 1985 and 2007 I have never had to turn out due to emergency flooding. It has been four times since then."

Five years ago, flooding damaged a series of rooms in Calke Abbey in south Derbyshire. At the time, the site's property manager, Stewart Alcock, said heavy rainfall "is one of the big climate impacts threatening our built heritage".

Later that year, the severe flooding in Tewkesbury affected several National Trust properties, including Basildon Park. The 12th century Tewkesbury Abbey also had water come in through the doors. In 2009, the devastating floods in Cockermouth, in the Lake District, hit the birthplace of William Wordsworth.

National Trust employees had to wade through waist deep water to salvage the collection of furniture, artworks and documents. The floods also affected properties at Fell Foot, Low Wray Campsite and Ash Landing.

Ms Staniforth said: "Our emphasis must now be on prevention. We are trying to put aside more [money] than we ever have before to deal with this issue."

At risk the sites that are suffering

St John the Baptist in Woodhurst, Cambridgeshire

Calke Abbey in Derbyshire

Framlingham Castle in Suffolk

Tewkesbury Abbey

Castle Acre Prioryin Norfolk

Norwich City Wall

William Wordsworth's House