Max Fordham House, London

Case study: The concrete-framed house that the environmental engineer designed and lived in was the culmination of a career spent finding ways to reduce the energy our buildings consume. His legacy offers a glimpse of a potential zero-carbon future

The Max Fordham House in north London has become the first home to achieve net zero for both embodied and operational energy-related emissions, in line with the UK Green Building Council’s Net Zero Carbon Buildings Framework. As measured in 2020, the total building annual consumption was 8.1MWh. This equates to 48kWh/m²/yr, 20% less than the required net zero carbon compatible RIBA 2025 target of 60kWh/m²/yr.

The house, which was designed and lived in by the legendary environmental engineer Max Fordham until his death earlier this year, was designed around a reinforced-concrete frame. For Fordham, this project was the culmination of a life’s work on sustainable buildings, and it was important to him that the house was constructed using readily available materials, allowing its lessons to be replicable on more affordable schemes. The simplicity of the house’s architecture also reflects Fordham’s own engineering philosophy of keeping things practical and unassuming.

“Simplicity does go a long way,” says Ali Shaw, principal engineer at Max Fordham. “If things are simple, people have the time and attention span to focus on them as much as they need to. When they are complex, people just don’t have the time to think through all the possible issues.” The concrete frame comprises a 300mm ground-floor slab, 185mm upper-level slabs, 200 x 200mm columns and 200 x 400mm beams. To reduce embodied carbon, a 50% GGBS mix was specified throughout.

The total upfront embodied carbon emissions are calculated to be 102 tCO2e from lifecycle stages A1 to A5, 45% of which relates to the structure. To achieve net-zero carbon for the upfront embodied emissions, verified offsets were purchased for a biodiverse forest planting scheme in Panama and a wind power project in India. The structure, which is entirely within the highly insulated thermal envelope, plays an important role in the passive heating and ventilation strategy. There is no heating system, and interior temperature varies between 20-21˚C all year round. The house is passively solar heated during the day, while the thermally massive structure and automated, insulated window shutters help retain this heat throughout the night.

As the house is designed not to need any heating on the coldest day, it needs to be able to dispel heat on every other day. Again, the thermally massive structure and wide-opening windows help with this. Cold fresh air is brought into the building from beneath the car undercroft and supplied silently to inhabited rooms at high speed through 3D-printed jet nozzles. Summer overheating is kept to a minimum, with the internal temperature going above 25˚C less than 1% of the time. “If it didn’t have a lot of thermal mass in the building, it wouldn’t be as comfortable in very hot weather,” says Shaw, “but I think it’s unlikely it would have had cooling installed. It just would have overheated.”

Domestic hot water is supplied by a heat pump and electricity is 100% renewable – a quarter of it being supplied by the house’s own 24m2 photovoltaic array.

Photos: Lydia Goldblatt, Tim Crocker