Retrofit Is RIBA South West Building of the Year

It's all about the embodied carbon that you save compared to building new.

Great Brockeridge rear
Great Brockeridge rear.

Guy Sargent

We have called upfront carbon the issue of our times. With our limited carbon budget to stay under 1.5 or 2 degrees Celsius, every kilogram of carbon that can be saved by renovating a building instead of demolishing and building new is important. That's why projects like the Great Brockeridge House in Bristol, United Kingdom, are so important. Designed by Contemporary and Sustainable Architecture, aka CaSA, the architects took a house that was really too ugly to live in, and renovated it so that it is attractive, comfortable, and efficient in its use of operating energy, but also with low upfront or embodied carbon.

Before and after
After and Before.

CaSA Photography

Completed in 2020, the house recently won the Royal Institute of British Architects (RIBA) South West Building of the Year. Judge Fergus Feilden said, "Great Brockeridge is an intelligent, exemplar refurbishment demonstrating how existing building stock may be retained, renewed, and upgraded through intelligent design, and an active and engaged client and design team."

Most architects either pay lip service to or ignore embodied carbon, but CaSA takes it seriously.

"Our initial proposal aimed to retain as much of the existing building as possible, reducing the materials required and therefore limiting the embodied carbon of the redevelopment," explains CaSA director Adam Dennes in a statement. "Though constrained by a modest budget, we did not hold back the creative design of dramatic contemporary spaces and utilised the opportunities for externally insulating and recladding to create a striking contemporary exterior."
Kitchen interior

Guy Sargent

This is not easy to do anywhere, but is particularly hard in the U.K., where there is a big Value Added Tax, or VAT, of 20% on almost everything you buy. To encourage housing affordability, the government exempts new housing from the VAT. As Will Hurst of the Architects' Journal campaign, Retro First, noted,

"One of the most significant barriers [to retrofitting] is something of a quirk, a distorted system of VAT which props up the industry status quo. We pay 20 percent VAT on most forms of refurbishment and renovation and typically between 0 percent and 5 percent on embodied carbon-guzzling new build. As the Building Better Building Beautiful Commission said, this 'effectively represents an incentive to rebuild, rather than to renovate,' despite the many 'social, economic and environmental' benefits of repair and maintenance."
View up at house front facade

Guy Sargent

The client of the Great Brockeridge house isn't too happy about the VAT either. In fact, he's outraged. "We didn’t want to knock the house down and start again," explains homeowner Simon Coulson. "I felt a little bit aggrieved, that you could knock the house down and start again, and not pay VAT, and save yourself 20% of the cost, but if you want to go to all the effort and all the hassle and accept all of the compromise that comes with retrofitting a house you somehow have to pay 20% more for the privilege. If the government is truly looking to push a low-carbon future, we can’t just be knocking down buildings every time we are unhappy with the aesthetics of them."

He went on: "I feel passionately about this, the government should be supporting building companies and individuals looking to make their homes more energy efficient. The VAT relief on new builds doesn’t really match up with what we're trying to achieve as a society which is to reduce waste and reduce emissions. The way to achieve this is to upgrade and improve our existing building stock by making it energy efficient. You can do that relatively quickly, relatively cheaply without wasting a lot of material along the way."

Though they do not use the term, the house has a lot of the features we associate with Passivhaus, or Passive House, design, including lots of insulation, triple-glazed windows, and a breathable membrane for air-tightness. "The remodelled roof and new build walls are all designed to perform above current building regulations, using highly insulated timber frames constructed with FSC sustainably-sourced timber."

Lower level and Ground Floor Plan
Lower level and Ground Floor Plan.


Existing walls were insulated on the exterior and then clad in new clay tiles, inspired by the little bit of Staffordshire blue bricks that were retained on the lower floor. The garage has been removed and replaced with a new entry to closets, utility areas, and bike storage; it appears that visitors walk up the stairs at the side to the main floor.

Looking up through stairs
Looking up at stairs.

Tom Glendinning Photography

We used to have a feature on Treehugger called the Stair of the Week, usually pointing out stairs in commercial or multifamily residential buildings that are so nice that nobody wants to take the elevator. Occasionally we would include one that is just interesting or unique, as this one certainly is; it "forms a beautiful and sinuous piece of carpentry at the heart of the house, stretching three storeys and balancing sweeping curves with precision connection details."

Side of stair

Tom Glendinning Photography

"The whole piece is constructed from planed ash and ash-veneered birch, complemented by a brass handrail with connecting brass dowels supporting the balustrades. Designed with the help of parametric design and delivered with the precision of CNC (computer numerical control) technology, the weight and balance of the stair feels carefully judged and responds to a light touch across the rest of the project."
view of skyline

Guy Sargent

Architect Dennes says the house is "an exceptional example which is attainable by many, not just a few. "We hope that Great Brockeridge will inspire innovative energy-saving renovation projects across the UK." Let's hope also that it will inspire politicians to change the silly, senseless tax rules that promote new construction over renovation. We need more of this.