Passivhaus Affiliate
Header Image

Cannock Mill Cohousing

Location: Colchester, Essex
Completion Status: Completed 2020 Occupancy: Occupied since December 2019
Architect: Anne Thorne Architects LLP Consultant: Client-side Passivhaus designer: Junko Suetake/ Anne Thorne Architects LLP, Contractor-side Passivhaus designer: Etude, Thermal bridging calculations: Elemental Solutions, M&E Design: Alan Clarke
Contractor: Jerram Falkus Construction Client: Cannock Mill Cohousing
Certification: 2019 & 2020, Passivhaus Certifier: WARM
  Share this project: 

2023 UK PAssivhaus Awards Finalist

WINNER in the 2023 UK Passivhaus Awards residential new build category. Sharing is caring! This alternative housing development is combatting loneliness & climate action together. 

Cannock Mill Cohousing has been a labour of love for the group who brought the project to fruition over many years. The project combines Passivhaus comfort and efficiency with shared community space and low carbon living. It is the second Passivhaus certified cohousing scheme in the UK following the success  of Lancaster Cohousing

The 23-home development is comprised of three separate Passivhaus certified buildings of 1-3 bedroom flats and houses:

  • 5 house block
  • 12 house block
  • 6 flat block

Cannock Mill Cohousing. Image credit: Anne Thorne Architects


A converted listed mill building is used as the ‘common house’ with a shared kitchen, laundry room and community space. There is shared garden as well as private outdoor space.  The houses are designed to lifetime home’s standards with a space for a future lift and wide staircases to accommodate a stairlift.

Cannock Mill Cohousing   I   Anne Thorne Architects. Quote:

Key stats

  • Number of units:  23 (1-3 bed flats & houses)

  • Construction: Timber frame

  • Construction started: April 2018

  • Completed: 2020

Cannock Mill Cohousing scheme. Image credit: Anne Thorne Architects



Cannock Mill Cohousing is a mutually supportive community with some shared facilities, encouraging social contact and individual space in a community managed by themselves, the residents. All residents agree to the aims and objectives of cohousing, which includes a commitment to consultation and consensual decision making. The residents share many things including cars, ebikes, a ‘library of things’ and more. 


Cannock Mill Cohousing   I   Anne Thorne Architects. Quote: We were concerned about being isolated in our houses in London. We also liked the idea of sharing a lot of things, which reduces expenditure and carbon emissions and makes it more sustainable.


Cannock Mill Cohousing_Foundations. Anne Throne Architects

Cannock Mill Cohousing scheme under construction

Cannock Mill Cohousing scheme under construction

Cannock Mill Cohousing scheme under construction


Walls: Timber frame with Warmcel insulation

  • Flats: 0.092 W/m2K

  • Houses: 0.108 W/m2K

Cannock Mill Cohousing staircase. Image credit: Anne Thorne Architects

Floor: Reinforced concrete with phenolic insulation (flats)/ PIR insulation (houses)

  • Flats:  0.108 W/m2K

  • Houses:0.135 W/m2K

Roof: Timber frame with Warmcel insulation. Green roofs for houses.

  • Flats:   0.079 W/m2K

  • Houses  0.111 W/m2K

Building Performance

Predicted energy performance


Treated floor area

Form factor

Space heating

Heating load

Overheating risk

5 house block




10.44 W/m2


12 house block




10.2 W/m2


6 flat block




10.2 W/m2



Measured energy performance

Averaged final airtightness tests and combined electricity & gas bills 2020.


0.6 ACH @ 50 Pa

Garage/ studio space at Cannock Mill Cohousing. Image credit: Anne Thorne Architects

5 house block

41.28 kWh/m².a

12 house block

40.85 kWh/m².a

6 flat block

65.51 kWh/m².a

All results fall within predicted performance in PHPP. 


Cannock Mill Cohousing   I   Anne Thorne Architects. Quote



Sloping site: The houses had to be designed into a 11 metre  (from the top of the slope to the bottom)  north facing slope. To ensure that the houses could be south facing and optimise solar gain the houses were designed ‘upside-down’ with the balconies and living rooms on the top floor.

Cannock Mill Cohousing scheme. Image credit: Anne Thorne Architects

Drainage: The scheme has a sustainable urban drainage system to prevent flooding from heavy rainfall. Rainwater from the project’s deep green roofs is taken into temporary storage under the road, which then goes into the mill pond and on into the river.

Planning requirements:  The planning department insisted on two and a half car parking spaces per unit, even though many of the residents do not have cars. For Passivhaus projects it is usually easier if garages are located outside the thermal envelope. However, for this project the most efficient option was to install them as garages within the thermal envelope. This was achieved by using very thermally efficient and airtight bifold doors for the garage space. The garage space is most commonly used by residents as studios or workshop spaces and there is a car club for shared cars.



Key team

Client: Cannock Mill Cohousing

Architect: Anne Thorne Architects LLP

Quantity Surveyor: Peter Gittins & Associates

M&E Design: Alan Clarke

Contractor: Jerram Falkus Construction

Structural Engineers: Ellis & Moore Consulting Engineers

Thermal bridging calculations: Elemental Solutions

Passivhaus consultant (to contractors): Etude

Passivhaus certifier: WARM

Air testing: Paul Jennings at Aldas

MVHR & Windows & doors: Green Building Store

Lacuna bifold doors: Passivhaus Store

Warmcel insulation (for wall & roof): PYC Group

Cannock Mill Cohousing scheme. Image credit: Anne Thorne Architects


2023 UK Passivhaus Awards: Cannock Mill Cohousing - poster 2023 UK Passivhaus Awards: Cannock Mill Cohousing - presentation

"I’m now a total convert (to cohousing). They’re doing many fantastic things on site and a strong sense of community is developing. They have a lot of people from different backgrounds and they’re great at problem-solving together. What they have achieved is a triumph."

Junko Suetake, Passivhaus Designer working with Anne Thorne Architects

Kitchen at Cannock Mill Cohousing. Image credit: Anne Thorne Architects


Further information

Cannock Mill Cohousing

Previous PHT story: Progress for Cohousing striving for Passivhaus – 13 June 2016

Previous PHT story: Cohousing scheme gets green light for 23 Passivhaus homes – 11 August 2015 

Previous PHT story: LoCo Cohousing gear up to build Colchester Passivhaus development – 29 July 2014

Anne Thorne Architects Cannock Mill Cohousing

Suetake Studio 2 Cannock Mill Cohousing

2023 UK Passivhaus AwardsBack to 2023 UK Passivhaus Awards