How we designed a Net-Zero canteen for Kew

Arboretum HQ, RBG Kew

How we designed a Net-Zero canteen for Kew


BREEAM	Outstanding and energy in use Net Zero
Contract value	£4.5mn
Structural frame	Cross-laminated timber

The tree specialists at the Royal Botanical Gardens Kew were enduring poor welfare conditions and their 1960s building was at the end of its life. The goal was to give them the best canteen and office facilities that would support their valuable work in the UNESCO World Heritage Site. The sustainability brief required a BREEAM Excellent standard.

Mulroy worked with Tony Kirkham and the Kew team to develop the existing planning approval to reflect the work of the arboculturalists. The building has a large canteen on the ground floor with other welfare facilities with offices and training rooms above. We enhanced the original design and exceeded the sustainability brief by obtaining the highest level of BREEAM Outstanding with an Net-Zero energy in use building.

We reduced the thickness of the timber structure and weight of steel structure that resulted in smaller foundations. Timber grown at Kew was used in the interior and each sample is stamped with Kew’s logo of authenticity. We designed the building with increased air-tightness so that the proposed air-conditioning could be omitted and we increased the number of solar photovoltaics on the roof.

We learnt a lot about the compost heaps within the surrounding yards and the toxic aerosols that they emit. Despite these we achieved a fully naturally ventilated building by having sensors that would operate roof vents for fresh air and Kew developed a management strategy for the maintenance of the heaps to reduce aerosol emission when the building windows would be open.