Our project refurbished a small derelict schoolhouse and converted it into our architecture studio, making a comfortable and uplifting space for us to work in. It combines low-carbon strategies with a listed building refurb. The schoolhouse was built in 1867 for the growing population of Battersea when Clapham Junction Station was built. The school closed in the 1960s, was used in an ad hoc way and then lay empty for 40 years. It is Grade II-listed and was on the Heritage at Risk register until we completed our refurbishment.When we started, the building fabric was in very poor condition. The north wall had a severe outward lean and was held up by scaffolding, and all walls had extensive cracking. Windows and doors were either missing or rotten. We used reversible techniques and like-for-like repairs to retain the character of the listed building, alongside a sustainability strategy focused on high levels of insulation (exceeding current Building Regulations), improved airtightness, low-carbon heating and re-use of materials.Walls were insulated internally by building an independent timber frame inside the existing brick walls, sat on a new structural concrete floor slab. We wanted to retain the character of the roof timbers, and so the roof is insulated externally above the sarking boards. Additional courses of bricks at the gables contain the additional roof build-up, which is concealed at the eaves with oversized gutters. Our office is on a busy road, so we have MVHR to avoid relying on opening windows for ventilation; heating is from an air source heat pump and hot water from a phase change thermal battery.Biba Dow, director, Dow Jones ArchitectsAdvertisementProject dataStart on site September 2023Completion Gross internal floor area 2Architect Dow Jones ArchitectsClient Dow Jones ArchitectsStructural engineer MomentumM&E consultant C+C BEApproved building inspector AssentMain contractor Silver Fern ConstructionSpecificationWe were keen to retain the scale and openness of the schoolroom, but also to make intimate areas in which to work. The teachers office has become our library and weve built a small timber building at one end of the schoolroom, which creates an upstairs meeting room and a downstairs space for lunch. We also enclosed the small yard at one end to make a kitchen and WCs.The meeting room has a large window overlooking our workspace, so views across the building are maintained. A cupboard is formed behind the undercut stair for our server and printer, and the MVHR duct makes a small seat at the top of the stairs.Construction was an exercise in circular material reuse. As we were insulating above the roof, we recycled the 1960s roof tiles into hardcore below the new ground slab. The old floor joists were set aside and used to build the meeting room structure. We then re-used the old pine floorboards as cladding for the stair and meeting room. The boards are around 27mm thick and 90mm wide; they are amazing quality, very straight and long. Our joiner took out the nails, planed them and sorted them into lengths, then used them to clad the outside of the meeting room and stair.Biba Dow, director, Dow Jones Architects