The final countdown: Kew’s magnificent Temperate House to re-open in three months' time

A lengthy and complex construction project, which has seen one of Kew's, and indeed London's, most iconic buildings closed to the public since 2013, is coming to an end. The last of the scaffolding has been removed, the final paintwork is being carried out, and the removal of hoardings draws near.  As these works progress, a brand new Temperate House, akin to a glistening glass cathedral, is slowly emerging from its encasement. Retaining its Victorian splendour yet embodying cutting-edge engineering, the Temperate House is on its final journey to reclaim its place as the world's greatest glasshouse. The true jewel in Kew’s crown, it will be a sanctuary for some of the rarest and most threatened plants from temperate regions across the globe.  
  
Made possible with support of over £15m from the National Lottery, this restoration project has been unlike anything Kew has ever undertaken. Originally designed by world-famous architect Decimus Burton, heritage architects Donald Insall have updated and modernised key features to enable it to function as a contemporary working space. Over 69,000 individual elements were removed from the building and cleaned, repaired or replaced. This included the replacement of a staggering 15,000 panes of glass, and the restoration of 116 urns which had to be carefully lifted off the building by crane. 
  
Twice as big as Kew's Palm House, the Temperate House was encased within a tent-like structure, large enough to cover three Boeing 747s, in order to carry out the painstaking work in all weather. Approximately 180km of scaffolding was needed for the restoration of this 20 metre high structure, about the length of the M25.  

A whopping 5,280 litres of paint was required, which painted a total area of 14,080 metres – about the same size as four football pitches. Over 13 different layers of paint were found in the oldest parts of the building, revealing a variety of different colours, ranging from cream to pale blue and peppermint green. The new paint system utilises four different coats, specially designed to protect the metalwork from corrosion, a robust process that is often used on oil rigs. 

As to be expected when restoring a Victorian building of great historical importance, the team were met with some surprises, perhaps the most fascinating of which was the discovery of original underfloor heating pipes, installed by a rather forward looking Decimus Burton 158 years ago! They have been safeguarded and remain protected underneath the flooring.  

The final phase will see a series of spectacular water features installed throughout the building, the pathways completed, and, perhaps the most intricate job of all, the cleaning of the windows that make up the entirety of this enormous 4,880 square-metre structure. 

Andrew Williams, Director of Estates and Capital Development at the Royal Botanic Gardens, Kew, says:  

"Five years ago, we erected hoardings around one of the world's most important buildings, which was in a state of disrepair. We looked ahead expectantly to an incredibly exciting challenge and journey of discovery, to completely refurbish almost every element of this magnificent structure and return it to its rightful place as the greatest glasshouse in the world.  

I am extremely proud to now be within touching distance of the opening date on 5th May. Thanks to a fantastic team and some incredible partners, including National Lottery players, we have not merely restored the Temperate House to its former glory, but have gone to extraordinary lengths to ensure it has been done to the highest possible standards befitting a building that both contains our heritage and embodies our future, enabling us to teach generations to come about the importance of plants to life." 

The experience 

Visitors to the Temperate House will ultimately find it a life affirming, all-consuming experience, and will leave feeling hopeful about the progress that RBG Kew and its partners have made. With over 250 years of plant expertise behind it, world-wide collections, partnerships spanning 110 countries, and 326 acres that make up the most biodiverse place on the planet, no organisation is better placed to be the global voice for plants than Kew. And no space is better designed for that voice to ring out - come May 2018 - than the Temperate House.  

Generous funding from the Heritage Lottery Fund, the Department for Environment, Food & Rural Affairs, philanthropic trusts and private donors, has made this project possible. Fundraising efforts continue in order to complete this ambitious restoration and ensure the building and its plants inspire future generations to protect and treasure the world’s biodiversity.