Palm House for major renovation

It is a large -scale makeover – it involves moving 1,300 plants, replacing 16,000 windows and cleaning hundreds of tons of iron.

This is the ambitious plan of 50 million pounds sterling to renovate the world renowned palm house, which is in the heart of Kew royal botanical gardens.

The hot and humid conditions inside have wreaked havoc on the building, which opened in 1848 and sheltered a tropical forest.

Kew will also use the renovation – which will see the glass house closed for five years from 2027 – to reduce the Palm House emissions to Net Zero.

The project building permit has now been submitted, and some of the factories that make up the interior tropical forest began to be moved.

“This is probably the plant that I worry about moving the most,” explains Thomas Pickering, head of glass houses.

He stands next to one of Kew’s most precious specimens: a plant called Altensteiniiwhich is a type of cycad.

He grows in a pot, and at 250, he is older than the Palm House herself. It is also huge – weighing more than a ton and standing about 4 m high.

“This is the size of it. It has a huge weight in this root ball, but also this incredibly long rod, which is very old because they are incredibly slow growth plants,” explains Pickering.

Horticulturalists will use scaffolding, supports and hugs to protect the plant when when the time comes to move. Other plants, which are a little easier to move, have already been taken to a temporary greenhouse.

“It will be a long -term project,” explains Pickering.

“And in the next two years, it will be a process to select the plants we need to contain (place in pots) and keep which we must propagate – and also some of the plants will be shot down because we will not be able to move them.”

The Palm House was built over 175 years ago and was a wonder of the Victorian age.

No one had ever built a glass house on this scale before and the engineers borrowed techniques from the maritime transport industry to build the enormous structure.

It was renovated for the last time in the 1980s, but now the iron is strongly rusty in places, it will therefore be returned to work in naked metal, repaired and repainted.

All thousands of single glazing windows will be replaced and tests are underway to find the best type of glass to provide maximum insulation.

Maintaining the temperature of the Palm House at 21C uses a lot of energy, but now gas boilers will be replaced by heat pumps at the air source and the water source.

“This is an incredibly difficult building to make Net Zero,” said Rachel Punard, head of sustainability in Kew.

“We can do a huge amount with things like seal glass and improve heating systems to massively reduce the carbon footprint and improve the sustainability of the Palm House without having an impact on aesthetics.”

The house of Lily, which is located next to the Maison de Palmier, will also be rendered as part of the renovation. The public will always be able to visit both for the next two years before being closed for the work.

The Kew team recognizes that it will be a large company that will have a temporary impact on people coming to their botanical gardens. But they say that the results will be worth it.

“The really important aspect of this is to try to make sure that the structure can last as long as possible, before having to make another renovation,” explains Rachel Punard.