Unigro builds world leading plant

quarantine house at Kew Gardens.

Case studies

Plant reception and quarantine facility at Kew Gardens


The Royal Botanic Gardens, Kew is a world famous scientific organisation, internationally respected for its outstanding living collection of plants and world-class Herbarium as well as its expertise in plant sciences, conservation and sustainable development in the UK and around the world.

Kew needed to replace its existing facility, built in 1979, in order to meet its operational needs and so that it could continue to meet its statutory obligations.

A Kew project team prepared an outline design for the Quarantine House, based on a comprehensive assessment of user requirements. This was then used to obtain planning permission, and after a successful tender, Unigro was appointed contractor.


The remit was to design and construct a quarantine facility, with containment and biosecurity the top priorities. The operation and maintenance of the building were also key considerations – to enable the building to operate efficiently and effectively and also to meet licensing requirements.


Construction commenced in July 2010, and on 14 September 2011, the new Kew Quarantine Unit was opened by the Parliamentary Under Secretary of State, Richard Benyon MP.

The facility employs the following containment features:

•    Double glazing to provide full containment security

•    Individual, isolated bays with precise controllable climates for temperature, relative humidity, day length and light levels 

•    HEPA filtered air change to maintain negative air pressure (pre-set to CO₂ levels)

•    Facilities to permit fumigation to counteract pest or disease outbreaks

•    Contained drainage to ensure waste water is sterilised

•    Secondary containment bunding system throughout 

The facility also contains the following energy saving features:

•    Efficient double glazing and external shade blinds system to minimise heat loss/gain

•    Efficient ventilation to recover heat from the extracted air

•    High efficiency internal and external lighting

•    Energy management system

•    Heat and coolth sink tanks to store surplus heat from the cooling system and provide heat for the building on demand. The tanks ensure continued operation of the glasshouse in the event of mechanical failure and enable a reduced chiller capacity utilising off-peak and CHP electricity.