The Garden Museum is housed in the deconsecrated grade II* listed church of St Mary at Lambeth.

In 2008 we built a two-storey gallery inside the church, which catapulted forward the museum’s development plan. The project created new galleries, an education room and storage, and consolidated the nave as an events space. The gallery building is made of CLT and is sustainable and reversible, meeting the challenges of environmental design in an historic context. This building allowed the museum’s many varied events and educational activities to flourish, and a new cultural offer to evolve. It generated a 400% growth in visitor numbers in the first year, and is cited by Historic England as an exemplary use of a former church.

In 2013 we won a competition to design a second phase that would extend the museum both within the existing building and out into the churchyard. Phase II brought the opportunity for the museum to create a new public face for themselves; being housed in a church building adjacent to Lambeth Palace, the museum is often mistaken for part of the palace. Our new building provides a much-needed urban presence by extending the museum as a cluster of bronze clad, timber frame pavilions that have a dramatic presence on the street.

The new garden pavilions provide a large and a small education room for a range of learning and community activities, and a café. The bronze clad pavilions are connected by a glazed cloister structure that frames a new garden with planting by Dan Pearson. In front of the pavilions is a new forecourt space that frames the existing porch and entrance to the museum, and has a planting scheme by Christopher Bradley-Hole.

The new buildings are clad in lapped bronze tiles designed to reflect the scale-like quality of the bark of the plane trees that surround the building. Plane trees were intro¬duced to Britain by royal plant-gatherer John Tradescant, who is buried in the churchyard and is the genesis of the museum.

The extension of the CLT structure inside the church provides more gallery space and an archive study room and store.

Our extension continues into the North Yard – a gap between the church building and the Garden Wall of Lambeth Palace – to create new staff offices and workshops, and other back of house facilities.

Developing the museum site has brought  many challenges; the churchyard is a significant archeological site, several of the tombs are listed, there are nine class A trees and protected views across the site to Lambeth Palace, all of which conspire to limit the developable envelope. Our scheme responds to these parameters whilst making a building that will have an iconic presence in the city.

The relationship between the precision of the new architecture and the patina of the old building, combined with the colour and texture of the landscape planting, creates a juxtaposition that defines the character of the museum. It has been described by Historic England as an “exciting and innovative project with the potential to set a benchmark for new work in the historic environment.”