A sustainable extension transforms BakerBrown’s converted forge

BakerBrown Architects crafts a sustainable extension for a converted forge project in southern England

The Old Forge, BakerBrown
(Image credit: Ivan Jones)

BakerBrown Architects has an award-winning reputation for sustainable architecture, pioneering ways of reducing a building’s footprint through meticulous design, careful use of resources, and thoroughly practical and attainable methods like insulation and the use of local materials and trades. In a similar vein, its latest work is a sustainable extension that makes the most of a unique site that brings together past, present and future.

The Old Forge, sustainable extension by BakerBrown

(Image credit: Ivan Jones)

The practice’s most recent project is a conversion of a long, low, gabled dwelling house in the south of England.

The original structure was once the village forge, making all manner of metal goods for local farmers and businesses. It was subsequently converted into a house and the surrounding neighbourhood upgraded to a Conservation Area.

Image of architectural sketch

(Image credit: Ivan Jones)

The clients approached BakerBrown with the intention of creating a better relationship between the house and its garden, set at 90 degrees to the original structure.

The architects also had to upgrade the original masonry building. Built in the era between insulation and proper damp-proofing, it was becoming uneconomical to run.

The Old Forge, extension

(Image credit: Ivan Jones)

The primary change is the creation of an extension that reaches out into the walled garden, transforming what was a modest sunroom into a large open-plan kitchen and dining room. A new red zinc pitched roof oversails the extension, providing solar shading for the glazing.

The main building has been overclad to radically improve its ability to retain heat in the winter and cool air in the summer.

The Old Forge, extension interior

(Image credit: Ivan Jones)

Outside, a new rainscreen has been made from locally sourced sweet chestnut, adding to the increased thermal performance of the building.

The original boiler was replaced with a heat pump; despite increasing the floor area by around 40 per cent, the combination of more efficient heat generation and better insulation has reduced the property’s energy consumption.

The Old Forge interior dinning area

(Image credit: Ivan Jones)

All the design details are carefully considered with energy-saving in mind. The polished concrete floor slab in the extension acts as a heat sink, drawing in warmth from the glazing in winter. Sustainable birch plywood is used for the kitchen, ceilings, and joinery, lightly oiled to reflect light, while traditional vernacular elements like the original flint wall are retained and exposed.  

Set up by Duncan Baker-Brown in 1994, the studio is based in East Sussex, and frequently works with vernacular forms, existing buildings, and conversions. Past projects include The Waste House – made, as the name suggests, from waste materials; and The House That Kevin Built, prefabricated using 90 per cent bio-based materials and the UK’s first EPC A* rated home. In 2017, BakerBrown authored The Re-Use Atlas: A designer’s guide to the circular economy, a pioneering book looking at how architects can make better use of limited resources.



Jonathan Bell has written for Wallpaper* magazine since 1999, covering everything from architecture and transport design to books, tech and graphic design. He is now the magazine’s Transport and Technology Editor. Jonathan has written and edited 15 books, including Concept Car Design, 21st Century House, and The New Modern House. He is also the host of Wallpaper’s first podcast.

With contributions from