Grainhouse is a complex, heritage-led refurbishment unifying and extending five historic buildings in Covent Garden. This new mixed-use development includes retail, leisure and office spaces.

Grainhouse unites five historic buildings , which were overlooked, underused, and at risk of demolition, in the heart of Covent Garden. Built at different times on a site dating back to 1861, these buildings have a rich history, having once housed a seed merchant company, brass and iron founders, and a non-conformist chapel. The layered architecture of the site embodies the lively history of Covent Garden and the designs draw heavily on their original uses.
Now, as an exemplar of a large and complex refurbishment, Grainhouse is the UK and European headquarters for global real estate investor Hines, with their offices spanning three upper floors. There are two additional office floors below with various occupiers, resulting in a total of 67,000 sq ft of prime office space across five floors. Ground and basement levels have been transformed into retail and restaurant units, enhancing the vibrancy of the area.
The design approach focused on retaining the existing facades and structures, as well as combining and extending individual buildings, resolving level differences with a central atrium, and using a new steel frame and lightweight concrete slabs. This preserved the charm of the original buildings while delivering highly efficient and modern workspaces. The project's foremost sustainable measure was retaining the original fabric and structure, resulting in a 61% reduction in carbon emissions compared to a new build.
The workspaces have been designed to prioritise health and wellbeing, with minimised operational energy and carbon use, achieving BREEAM Excellent and WELL Platinum certification.
Retrofit is often perceived as complex and costly compared to new build, however, it offers a susta

“It’s rare to have the opportunity to work on such a large historic site in this part of London, with such an array of existing buildings to reinvent. Stitching together five distinct buildings into one seamless whole was a creative and technical challenge that we greatly enjoyed, and which demonstrates the potential for complex historic buildings to be transformed into flexible, light-filled spaces that more than meet the needs of 21st Century occupiers.”

Jonathan Allwood, Director, Barr Gazetas