Copper Cupola at
royal botanical gardens, kew
We were commission as Copper Roofing Specialists, to replace the copper cupola on this Grade II listed chimney at the Royal Botanic Gardens in Kew. Designed by the architect Decimus Burton, it was originally called the “Shaft of the Great Palm-Stove”, but is now known as the Campanile. Its total height is 107 feet (33 m) and its purpose, even to today, is to heat the Palm House.
The original copper cupola was estimated to be roughly 170 years old and at this time copper was created in small sheets, which created more double lock cross welts on the roof (original roof shown opposite).
Originally two coal fired boilers were installed in the tower and coal was brought via a light railway running in an underground tunnel, but the tunnel is now clear of tracks and carries piped hot water to the Palm House from oil-fired boilers within the tower.
To gain access to the roof I had to go through those tunnels and climb up inside the tower using ladders attached to the internal wall, then through a narrow hatch located within part of the structure that looks like a bell house. However, you cannot gain access to the roof from this area and therefore steeplejacks were brought in to create a hanging scaffold for me to climb onto from that point and tools and materials were winched up to the area in the mornings before the gardens opened.
The original copper cupola was estimated to be roughly 170 years old and at this time copper was created in small sheets, which created more double lock cross welts on the roof (original roof shown opposite)
I carried out an inspection confirming that most of the cross welts on the original structure were now eroded and the decision was made to replace the entire roof. I also stated that as copper now came in coils it would be possible to rebuild the structure using the long strip method, but same design, thus adhering to the Grade II listing specifications, but with fewer cross welts – thereby giving the new roof an even greater longevity of life (as below).
I took precise measurements and photos of the original structure before the old copper was stripped and recycled. An interesting fact about this roof is that it was created using a concrete type base with wooden noggins placed into the concrete before it was set, acting as anchor points for the new battens to be fixed to.
The creation of the cupola took approximately 6 weeks and was created in pre-patina copper (already weathered green) to immediately match the heritage of the site. The exterior photo below shows the new copper cupola in place.