04 June 2019
Customer: Plymouth Community Homes Ltd
Value: £10.4 million
Duration: 94 weeks
Completion Date: June 2018
Contract Type: JCT Design & Build 2011
Procurement Type: Negotiated
Framework Agreement: HCA Delivery Partner Panel 2
Winner - ‘Sustainable Project of the Year’ in the 2019 Construction News Awards
Winner - 'Project of the Year - Building Projects' & 'Winner of Winners' in the Constructing Excellence South West Built Environment Awards 2019
Highly commended for Best Social or Affordable New Housing Development in the 2019 LABC South West awards
Shortlisted for 'Community Benefit' and ‘Residential’ categories in the 2019 South West RICS Awards
Shortlisted for the ‘Sustainability' and ‘Value' awards in the 2019 Constructing Excellence South West Built Environment Awards
Finalist for ‘Project of the Year (under £20m)’ in the Constructing Excellence South West Built Environment Awards 2019
Finalist for 'Best Residential Development (over 71 homes)' and 'Best Affordable Housing Development (over 71 homes)' in the 2018 Inside Housing Development Awards
Finalist for Best High Volume New Housing Development in the 2019 LABC South West awards
Largest Passivhaus certified scheme in the UK
Secured By Design Gold Award
Average CCS score 41.5
CCS Performance Beyond Compliance Certificate
Supported 13 apprentices
Diverted 100% of waste from landfill
This flagship development of 72 innovative and affordable homes, which are so eco-friendly they require virtually no heating, has helped reinvigorate a deprived area.
Mi-space delivered the project in partnership with Plymouth City Council. The development added much needed homes to the city’s housing register, with 23 homes to buy through shared ownership and 49 for affordable rent.
Currently the largest Passivhaus development in the UK, this estate is alleviating the issue of fuel poverty for its occupants through an innovative, modern standard of construction; providing superior energy performance through the use of high-insulation materials, and resident comfort through specialised ventilation systems. Mi-space exceeded contractual requirements of Passivhaus principles to deliver a fully Passivhaus-certified scheme. Primrose Park combines modern architecture and community values, reflecting a traditional village layout with a central square.
The scheme had a key funding condition of a 27% improvement on Building Regulations for operating performance.
Delivering an affordable Passivhaus-certified housing development within the client’s budget.
Achieving simplicity of construction whilst maintaining a high quality standard and achieving the levels of robustness necessary for the energy performance.
These innovative and low-energy homes – with their air-tight insulation, triple-glazed windows, improved thermal performance and reduced need for conventional heating – deliver lower emissions through their life cycle. Passivhaus delivers energy savings of up to 75% compared to other new builds, with only 1.5m³ of gas required to heat one m² of space per year; U-values of less than 0.15W/m²K and some roofs reaching U-values less than 0.13W/m²K. These air-tight, well insulated homes require less heating in winter and remain cooler in summer, reducing emissions and tackling fuel poverty for its residents. Residents reported they were comfortable in their homes during a period of heavy snow, and noted the low use of power to heat their homes. One resident also commented that they had not had any asthma attacks since taking occupation of their Passivhaus home, which provides continuous fresh filtered air through specialised ventilation systems.
Mi-space exceeded contractual obligations to deliver 100% Passivhaus certification for the project, completing on time and to budget, by implementing successful planning and coordination with stakeholders and site workers. Mi-space overcame unique challenges to achieve Passivhaus certification whilst remaining affordable. Primrose Park surpassed the required heat transfer targets set at design stage, achieving temperature consistency and airtightness figures at construction that are 95% lower than targets. The scheme features specialised ventilation systems, providing efficient heat recovery whilst reducing energy consumption. Mi-space used insulated raft slabs, solid concrete foundations that sit within an insulated box, achieving the required airtightness and U-values whilst reducing programme time with less excavation. Mi-space completed three air permeability tests per home, surpassing the Passivhaus requirement of no more than 0.6 air changes per hour with dwellings testing 0.25 air changes per hour. The completed homes have an average air permeability (m³/(h.m²) at 50Pa) rating of 0.46, against the maximum of 10.00.
Mi-space worked closely with the architects, engineers and Passivhaus designers from preconstruction, to manage challenges. The team’s solutions and technical achievements included: using the site’s sloping topography to benefit from solar gain; using masonry in place of structural insulated panels to deliver thermal requirements at reduced costs for the customer; high levels of insulation; triple-glazed windows in an insulation zone for thermal bridging; detailing for the foundations, windows and doors designed to reduce the risk of cold bridging; and specialised ventilation units that provide fresh, filtered air and prevent condensation. Our processes included collaborative early design reviews with specialists, beginning negotiations during planning to offer cost effective solutions, including the use of Smartply (a ply board with plastic cover that creates an impermeable membrane underneath the roof trusses) to create the first floor ceilings to further improve air tightness. We identified an alternative structural solution at tender stage, using masonry in place of structural insulated panels to deliver thermal requirements at reduced costs for the client and give a more robust air tight line. The management team implemented Collaborative Planning, which linked to milestone payments for subcontractors, with payments made upon successful completion of works. The project manager signed works off for quality and hitting programme targets before making payment, ensuring subcontractors completed works to deadline and to a high standard.
The project team created five work placements for people in education; 15 for those not in education; attended 13 construction careers information and guidance events; helped workers to gain 35 qualifications; and created and safeguarded 13 apprenticeships.
Mi-space supported the local community with a range of initiatives including leading two community litter picks, clearing an area of woodland and helping create a community path. The site hosted regular tours from local schools and colleges, with a total of 129 students and pupils visiting the project.
Primrose Park has received positive feedback, with one resident explaining how moving into her Passivhaus
home has improved the health of her young daughter, who has suffered from lung problems since birth.