Driven by a mandate to preserve an old-growth sumac tree in the rear garden, the architects created a curved reclaimed timber-clad addition that left the root structure undisturbed.
Johan Dehlin Driven by a mandate to preserve an old-growth sumac tree in the rear garden, the architects created a curved reclaimed timber-clad addition that left the root structure undisturbed.

In the London borough of Tower Hamlets, east of the bustling city, a pair of historic weavers’ cottages conceals an unlikely addition: A sweeping glass-enclosed ramp that culminates in a curving, timber-clad volume that deftly navigates the existing garden landscape. Designed for The Guardian architecture critic Rowan Moore and his family, the addition was intended “to make the house as accessible as possible,” says Stephanie Macdonald, a director of London-based 6a Architects. Moore’s wife Lizzie has multiple sclerosis, and was spending more and more time in her wheelchair as the renovation process began. “I don’t think she realized how trapped she’d become in one room,” Macdonald says.

As it stood, the house was not easily navigable in a wheelchair: The two weavers’ cottages were combined into one dwelling in the 1970s, but they were not originally built at the same level, requiring stairs to get from one to the other. A veranda built in the 1980s, which was also accessible only via stairs, connected the two structures, and offered views of the back garden a half-story below.

View from the southeast, showing the wood-clad volume that holds the bathroom and bedroom.
Johan Dehlin View from the southeast, showing the wood-clad volume that holds the bathroom and bedroom.
Large windows overlook the deck built around the sumac tree and allow natural light to flood the interior.
Johan Dehlin Large windows overlook the deck built around the sumac tree and allow natural light to flood the interior.

  Under the circumstances, finding a solution for a typical client would be challenging. Doing so for an architecture critic is downright daunting, but MacDonald was not deterred. “It just meant that we could have a great conversation about it, and that he was really engaged and involved in the details,” she says. “We tend to find with clients that the stronger their opinions, the better the project.” Here, opinions were in no short supply: In addition to making the house and garden accessible, the clients wanted to highlight their lush plantings and preserve old-growth trees.

Macdonald and her team responded by creating a glass-enclosed ramp that connects the two existing weavers’ cottages and slopes down into the garden below. Perpendicular to the ramp, a long and narrow wood structure is clad in reclaimed jarrah timbers—“they were quite old gnarly pieces of wood,” Macdonald says, “our contractor stitched them together”—dipping around an existing sumac tree, skirting past a mulberry and a birch tree, and stopping just short of a looming eucalyptus.

Looking back past the addition, the new glazed ramp that was added to the back of the two existing cottages. Because the property has a Grade II historic listing, all changes to the structure had to be designed to be reversible.
Johan Dehlin Looking back past the addition, the new glazed ramp that was added to the back of the two existing cottages. Because the property has a Grade II historic listing, all changes to the structure had to be designed to be reversible.
Glass-enclosed ramp connecting to two weavers' cottages and leading down to the new addition.
Johan Dehlin Glass-enclosed ramp connecting to two weavers' cottages and leading down to the new addition.

  Inside, wood also was used to clad the doors, ceilings, and walls, and all the surfaces were painted white to enhance the daylight that pours through the south-facing windows. The curving hallway culminates in a bathroom and master bedroom, where, MacDonald explains, “you can lie in bed and look out into the garden and see what is going on, bringing the garden inside and making it more present in the internal spaces.” And best of all, she adds, “now [Lizzie] can get outside whenever she wants.”

The interior of the timber-frame addition is also clad floor-to-ceiling in wood. The panels are painted white to maximize the daylight that enters through the south-facing windows. This hallway leads from a new bedroom suite back to the glazed ramp and historic cottages.
Johan Dehlin The interior of the timber-frame addition is also clad floor-to-ceiling in wood. The panels are painted white to maximize the daylight that enters through the south-facing windows. This hallway leads from a new bedroom suite back to the glazed ramp and historic cottages.
View of the addition, with its pitched roof, and the surrounding garden from the west.
Johan Dehlin View of the addition, with its pitched roof, and the surrounding garden from the west.

First-Floor Plan

A–A1 Section

Project Credits

Project Tree House, London
Architect 6a Architects, London—Stephanie Macdonald, Tom Emerson, John Ross, Alice Colverd, Cécile David (project team) 
Structural Engineer Price & Myers 
Contractor John Perkins Projects 
Building Control MLM 
Garden Design Dan Pearson Studio; Mark Cummings Garden Designs 
Size 57 square meters (613.5 square feet) 

Materials and Sources

Blinds Ace Contracts acecontracts.net
Cladding Ashwell Recycled Timber Products ashwellrecycling.com
Lighting Izé ize.info; designed by David Kohn Architects davidkohn.co.uk