Royal HaskoningDHV has been working with the Royal Botanic Gardens at Kew on a wide range of restoration, renovation and refurbishment projects since 1974. Our own Structural Engineer, Graham Wright, has been providing his technical expertise to Kew since 1988, offering specialist structural advice to Kew’s Building and Maintenance Team.

One recent project involved the construction of a major display in the Princess of Wales Conservatory, featuring full length tree trunks in a woodland setting. Graham carried out a series of structural load checks on the frame of the building so that the huge tree trunk sections could be safely hoisted from the steel main frame without causing undue stress to the glazing.

The tree trunk sections were cut to around 1.6m high by 0.8m wide, then connected with a joggle joint before being bolted together. Each ‘tree’ was made up of four trunk sections, weighing up to a maximum of 725kg.

“Kew Gardens has given me the rare privilege of working with important historic structures over a long period. It continues to offer interesting challenges with each visit.”

Another typical project was a structural appraisal of the 10-storey high Pagoda, which dates from 1762 and is due to open for limited public access in 2009. The appraisal needed to establish whether the building was structurally sound and the number of people it could accommodate at any one time.

A comprehensive inspection included taking enough measurements to determine the maximum span, spacing and size of the timber joists at each level, along with a recording of visible defects. This was followed up by structural calculations to confirm the load capacity of each floor, which in turn told us the number of people that could be safely supported.

More recently, we’ve also carried out a structural appraisal of the Temperate House, which was the first building we were involved with back in 1974. A full renovation was carried out between 1974 and 1980 where we provided civil, structural, mechanical and electrical design services. Since then, we’ve carried out similar appraisals on the building every three or four years.

Between 1984 and 1988 we were asked to carry out anothermajor renovation, this time at the Palm House, which waserected in the mid-19th Century and was the first buildingto use wrought iron for its main structural members. Again,follow up structural appraisals have been conducted everythree or four years since.

Other buildings at Kew that we have been involved withthrough restoration or construction projects include:

  • the Water Lily House (renovated 1992);
  • the Secluded Garden (built 1994);
  • the Evolution House (1994);
  • the Lower Nursery (1997);
  • the Orangery (1999);
  • the Nash Conservatory (2002).