Ramboll UK completes work on world's largest Victorian glasshouse

As regeneration efforts continue to preserve the valuable biological and botanical legacy of Kew’s famous gardens, Ramboll UK has become the latest consulting firm to play a leading role in the project. The engineering firm oversaw the repair and improvement of Kew’s Temperate House, the largest Victorian glasshouse in the world, which opened its doors again in May 2018.

Kew’s Royal Botanic Gardens have been one of the UK’s top destinations for naturalists and the plant and fungi lovers among the general public for generations. The gardens, which are situated in Kew in West London and Wakehurst in Sussex, provide visitors and plant researchers with a haven to explore the diversity of plants. The locations attracted around 1.6 million visitors a year prior to their redevelopment, and were supported by a staff of around 800.

In total Kew hosts around 180,000 living plants, over two billion wild plant seeds at the Millennium Seed Bank and a historic library collection. As a result, Kew is also active in research, with more than 140 papers making their way into high impact journals last year. The dual tourist/research nature of the Kew’s economy means that it effectively raise awareness on key issues, from loss of biodiversity to how plants affect human well-being.

Lately, the gardens have been part of a major redevelopment project. As part of this, engineering and design consultancy Ramboll has been engaged in a 5-year, £41 million restoration project on Kew Garden’s Temperate House, which reopened to the public in May 2018. The Temperate House has been home to a selection of the world’s rarest endangered plants since 1863, however the Grade I listed building and UNESCO World Heritage site had deteriorated since previous restorations, the last of which occured in 2012, and had been closed to the public and placed on the Heritage at Risk register.

After an emergency fund-raising campaign, including an injection from the Heritage Lottery fund, in 2013 Turner & Townsend appointed Ramboll as lead consultant and conservation engineer to develop a scheme of fundamental repair and modernisation of key features. Initially it had been proposed to dismantle, repair and rebuild the entire structure – which would have jeopardised the entire project due to its major expensive – however Ramboll proposed that instead only the glazing system should be removed, so that work to the structural frame could be performed from scaffolding with minimal deconstruction. The much more cost-effective solution has resulted in improvements in daylight and ventilation, restoration of the opening lights used for ventilation, and the installation of a new building management system to enable greater environmental control within the building – better securing its precious environmental contents.

Mike Mittendorfer, Ramboll’s project lead, commented, ”The structure presented some unique and interesting engineering and conservation challenges. There was considerable corrosion and decay in the extensive wrought iron, cast-iron and steelwork comprising the structural frame. We are proud to see our innovative approach help return this very unique structure to its former glory and celebrate its vital role in preserving some of the world’s most important natural hertiage.”

Richard Barley, Director of Horticulture at RBG Kew, added, "Over the past few months, I have watched as some of the world's rarest plants finally reach their home. And what a home it will be - a glistening cathedral, the new glass allowing the sun to stream in, the ironwork restored to its glossy best.”

Recently Kew also appointed consultancy Mott MacDonald to lead a multidisciplinary team as part of redevelopment plans. The firm was drafted in for its expertise in building, structural and civil engineering, project management and cost advisory to deliver the project’s goals, including the refurbishment of iconic buildings such as Kew’s Victorian Palm House, designing and building new nurseries and catering facilities, and critical infrastructure projects at both sites.