A £3.8 million project to repair the roof at Dyrham Park is underway.

The work, vital to safeguard the future of the historic house in Dyrham, has been able to start thanks to the generous support of over 10,000 people who have donated money towards the roof appeal.

Scaffolders are working on site to start putting up the first of 500 tonnes of scaffolding which will eventually cover the house and include a viewing walkway with an accessible lift to allow visitors to see the roof repairs from early in May.

The roof is more than 200 years old and no longer protects the building's rooms and collections from the elements.

Project manager, Colette Cuddihy, said: “As a charity, the National Trust relies entirely on donations, grants and legacies as well as its membership and retail income. The support shown by the public for this project has been tremendous and we are very grateful to them and to our volunteers at Dyrham Park who have helped make this happen.

“Visitors to Dyrham Park will see the building being slowly covered in scaffolding over the next couple of months and we will spend the whole year replacing the 46 tonnes of lead on the roof and 8000 Welsh slates. There will also be repairs to stonework and a new woodchip biomass boiler replacing an obsolete and inefficient oil boiler.

“With water leaking through the lead covered roof, the future of the house and its important original collection depended on us being able to do these vital repairs. We have had a very generous response to the appeal with a lot of people giving small amounts which really adds up.”

The traditional sand-cast lead roof of the house at Dyrham Park has reached the end of its effective lifespan and over the last 25 year various repairs have taken place.

The existing lead will be recycled and with new lead cast into new sheets which will be thicker but narrower. This will reduce shrinkage and expansion caused by changes in temperature which has led to cracks and leaks in the existing roof.

The general manager of National Trust property Dyrham Park, Cath Pye, raised more than £5,000 towards a major refurbishment project at the house by running from Chipping Campden to Bath in a week, as part of a £500,000 public appeal to fix the leaking roof on the 17th century mansion house.

The remaining funds were offered through the National Trust and further grants.

Dyrham Park contains some of the original Dutch-inspired interiors and a priceless collection of furniture and objects collected by 17th Century colonial administrator William Blathwayt including a rich collection that includes superb Dutch art and ceramics of the period.

Three-quarters of those objects have now been carefully packed away in stores to protect them during the building work but by February 14, when the gardens and tea room re-open, an exhibition, 'Building Dyrham' will open showing how the house was originally built as well as explaining the work being done to repair the building.

Eilidh Auckland, house and collections manager, said: “In a normal year we would expect to have 160,000 people visiting Dyrham Park and we will be staying open during 2015 and giving people a chance to see the building work going on.

“The new activities, exhibition and displays are thanks to a grant of £85,000 from the Heritage Lottery Fund.

“From March 2015, people will be able to visit Mr Blathwayt’s apartment to see, hear, smell and get a feel for the seventeenth century, where we will also have a professional harpsichord player supported by some volunteers. And there will even be a chance to taste 17th century spiced drinking chocolate. We will also have a new exhibition that explains the history of Dyrham Park from 1692 up to and including the roof project, and the rooms used to store the collection will also be open to allow some highlights from the collection to be seen while the repair work is in progress.”

Away from the house, in the park, visitors will be able to enjoy some new walks, family trail and spend time in the revamped Old Lodge natural play area and spot some fallow deer.

The repair work should finish in mid-2016.

More information on the project is available from: www.nationaltrust.org.uk/dyrham.