Agar Grove Phase 1A

Location: Camden, London
Completion Status: Block 1A Completed	Occupancy: 1a occupied since April 2018. Tenants moving in as each block is completed
Architect: Lead design: Hawkins Brown, Passivhaus & delivery: Architype	Consultant: Client-side Passivhaus designer: Max Fordham LLP, Contractor-side Passivhaus designer: Architype, Contractor Passivhaus site support: Enhabit, Contractor site Consulting engineer: Elemental Solutions
Contractor: Hill Partnerships Limited	Client: Camden Council
Certification: May 2018, Passivhaus	Certifier: WARM
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Winner of the Large Projects category of the UK Passivhaus Awards 2021. The first phase of an ambitious council housing regeneration scheme in North London. The redevelopment of Agar Grove in Camden tackles fuel poverty, occupant wellbeing, & climate action pledges.

It's on track to become the UK's largest residential Passivhaus development when complete. In May 2018, it took a big step towards that end as the first block of 38 social rented homes achieved Passivhaus certification. 

 

Built in the 1960s bounded by a busy road and two mainline railways, the 249-home estate in Camden is part of the Council’s Community Investment Programme and will almost double the amount of housing available on the same site after regeneration. The project will be cross-subsidised by future private sale phases with the budget for the first phase at £9m. The phasing of the scheme allows the option for most tenants to be moved from their old housing block to new homes as and when they are complete. 

 

Key Stats No. Units: 38 phase 1a Number of occupants: 105 Form Factor: 1.6 TFA: 3265m² Gross External Area (GEA): 4875m2 Construction Costs: £2044/m2 GEA Construction: Concrete frame on internal rotary piles. Brick & reconstituted stone facade Heat source: Gas

 

Agar Grove, Phase 1 complete Image credits ©Hawkins Brown  Left: North facing façade. Right: South facing façade.

 

As can be seen from the images above, the north & south facades have very different treatments. The Northern façade has less glazing than conventional multi-residential projects, with insulated side panels making the openings appear more generous. The Southern façade gives shade in summer.  The low winter sun penetrates beyond the balconies, deep into the floor plan.

 

We are determined to tackle fuel poverty and reduce CO₂ without the need for complex energy systems with high lifetime costs. The Passivhaus approach provides thermal comfort and air quality in a way that alternatives do not match. Although this can increase the initial capital costs, Camden Council – as both developer and landlord – believes that it will see the benefits of this approach, in higher build quality and reduced maintenance costs over the lifetime of the buildings.’

Michelle Christensen, Camden Council

 

Construction

The form of the building is efficient, allowing insulation thicknesses below those conventionally associated with Passivhaus. The project uses standard construction products, so is replicable. 

Achieving the airtightness on this scale is easier in many respects, but much harder to test. To achieve the required levels of airtightness, the construction team undertook the largest ever pressure test of its kind in the UK. The air test took a full day, with eight separate fans and miles of cabling and pressure tubes across the complex shape and layout of the building.

Retaining a core group of skilled workers on site was pivotal to the successful delivery, and rare for larger construction sites visited by several sub-contractors.

The roof level communal MVHR system is unusual for multi-residential developments and allows easy access for maintenance, filter changes etc.

 

Measured Performance

Temperature, relative humidity (RH) and CO2 were monitored in 3 example flats. The data showed that internal temperatures rarely dropped below 21°C in winter, and only rose above 26 °C in peak summer months, with temperature peaks being rare.

 

All respondents felt the air quality was good. The feedback on summer temperatures was more mixed and has prompted Camden to help residents understand how to best keep their flats cool for example, not all were aware that closing blinds could reduce solar gains.  For more details on monitoring results, please read the 2021 UK Passivhaus Awards phase I submission slides

 

 

I’m absolutely delighted that the Hill team have successfully completed the first phase of this ground-breaking project.  It has been a very steep learning curve for us and I think it’s fair to say that we’ve had to go back to basics in some areas to learn how to build to these sorts of standards.  The teamwork across the whole site has been fantastic and it’s great to be able to see Camden residents moving into to their new super-healthy and efficient homes.  We’re now eager to move on and start the next phase.

Paul Ansell, Hill Production Manager - London Region.

 

Client-side team (contractor team) Client: Camden Council Architects: Hawkins Brown; Mae; (Architype) Main contractor: Hill Parternships Limited Structural engineer: Stantec Services engineer: Max Fordham (Robinson Associates) Passivhaus designer: Max Fordham (Architype)  Passivhaus site support (Enhabit) Consulting engineer: (Elemental Solutions) Passivhaus certifier: WARM Landscape architect: Grant Associates Employers agent, Project manager & QS: Arcadis

Agar Grove, Phase 1A Image credit ©Jack Hobhouse

 

Agar Grove is the largest development in our Community Investment Programme, bringing 216 new council homes to the area and 37 at affordable Camden Living Rents.  The first homes completed on the estate are spacious, modern and some of the most energy efficient in our portfolio, making them more sustainable for both the environment and our tenant’s heating costs. 

Councillor Danny Beales, Cabinet Member for Investing in Communities at Camden Council.

Lessons Learned

The team successfully pitched Passivhaus and communal boilers by making a compelling case against the then-held view that all developments should connect to district heat networks (DHN). The work drew attention to DHN heat losses which were under-represented in modelling at the time. Running communal LTHW heating systems at low temperatures pushed the available technology to its limits because it was created for higher temperatures. In future developments, we are proposing low-carbon heat sources using ambient loop distribution: this technology is optimised to operate at low temperatures and is being used on Phase 1C. Model future designs to current whole-life carbon targets. Insulated side panels to the Northern façade do not perform as well as a full wall build-up.  Fully glazed, mainly landscape orientation of windows to Phase 1c should enable a greater amount of open able free area, for summertime ventilation. Thicker framed windows tend to perform better, these can be cloaked to maintain sightlines.  A full brick return is not ideal from a Passivhaus perspective as it leads to increased thermal bridging. Consider lining with a thin piece of masonry or metal.  There is value to having continuity in design input and completing the design for the contractor on a D&B basis.

Agar Grove was the first large-scale inner-city residential Passivhaus development in the UK, and its success has paved the way for more Passivhaus housing developments.

Phase 1b, of  57 homes, is soon to be complete with the next 115 at the commencement stage, retaining Hill Partnerships Limited as the main contractor. It is hoped Agar Grove proves the relevance of Passivhaus in the UK at scale and as an approach that aligns with local authority requirements on creating sustainable neighbourhoods rather than just one-off sustainable developments.

 

Unless otherwise stated, image credits © Jack Hobhouse

Further Information

Agar Grove 1a: 2021 UK Passivhaus Awards phase I submission slides

Agar Grove 1a: 2021 UK Passivhaus Awards video

Previous PHT story: Climate Action in Camden - 7 July 2019

Previous PHT Story: Agar Grove wins two London Planning Awards - 4th February 2019

Previous PHT Story: Students visit Agar Grove Passivhaus Estate Regeneration - 20th May 2017

Previous PHT Story: Agar Grove granted planning permission – 4 April 2014

Hill: Agar Grove receives Passivhaus Certification - 16 May 2018

CIBSE Journal: Max Fordham takes on Britain’s biggest Passivhaus – January 2016

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