The Category A Listed Palm Houses at the Royal Botanic Garden Edinburgh are the centrepiece of the public glasshouses and home to a globally important collection of exotic plants. They are reputedly the tallest Victorian palm houses in the world, and are outstanding examples of Victorian engineering. They combine innovative technology and classical architectural language into a remarkably slender and transparent structure which is both functional and decorative.
After more than 150 years, the survival of the palm houses and the plants they were protecting was threatened by corrosion of ironwork, stone decay and other water-related problems. They had to be closed in high winds and a safety net was installed to catch falling panes of glass.
We developed a comprehensive programme of best-practice conservation works, based on our thorough understanding of the history and significance of the palm houses.
We wrote the Conservation Management Plan and other necessary documents to support the client in successful grant applications for over £4m from the National Lottery Heritage Fund and Historic Environment Scotland.
Some aspects required us to depart from the original design. We made unobtrusive changes to gutters and downpipes to add resilience to climate change. The glass is laminated for safety and has a special UV-transmitting interlayer to support plant growth. Glazing sealants and paint are high-performance modern products replicating the appearance of the original. These changes were carefully considered and we had no difficulty obtaining Listed Building Consent.
We have worked closely with the contractor and specialist sub-contractors throughout the construction stage. In addition to usual architectural services, we have been the guardian of the conservation principles, using our judgement to decide whether a visible repair is acceptable and balancing retention of original fabric against replacement to reinstate the original appearance.
The restored glasshouses will impress visitors once again and will protect the irreplaceable plant specimens they were built to contain.