Cambridge Architecture CA81 by Cambridge Association of Architects

81 Cambridge Architecture

Spring/Summer 2021

Retrofit and reuse

Back to the future

Cambridge Institute for Sustainable Leadership

Building success

Cambridge Design and Construction Awards

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Contents

Contents 4-5 News

New garden at Peterhouse and consent for St John’s project; Northstowe homes craned into place; CAA Committee elections

7-9 Leading the (ex)change

A project is under way in Regent Street that could answer big questions about sustainable design

11 Roadmap to retrofit

22 In profile

Cambridge Architecture

We invite our sponsors to share a little more about their work

23 Social success

Susie Lober offers 10 tips to help you improve your digital marketing

24-25 The retrofit village

PAS 2035 training could be an opportunity for architects to upskill and get ahead of the curve

A Cambridgeshire village is leading the UK with a rural heat network powered entirely by renewable technology

13-15 Designing out waste

26-27 Rebuild or retrofit

16-19 Award triumphs

29 Change for change’s sake

How a circular economy can help supply chains deal with the challenges posed by Covid-19

Showcasing the winners at the CDCA

20-21 Retrofit ethics

Margaret Reynolds looks at ways to tackle the climate crisis without breaking the bank

The Secret Architect examines the case for Cambridge’s Park Street Car Park

Cambridge Architecture is a review produced by the Cambridge Association of Architects, the local branch of the Royal Institute of British Architects. The views in this magazine are those of individual contributors (named and unnamed), and not of the Association. ISSN 1361-3375 Any comments or for a copy of the magazine, contact editors@cambridgearchitects.org EDITORS David Adams, Tom Foggin, Susie Lober ADVERTISEMENT SALES Marie Luise CritchleyWaring (advertising@cambridgearchitects.org) Published by CPL

www.cpl.co.uk

Nick Kendall takes a look at the Future Buildings Standard, draft Approved Documents F and L

30-31 Work in progress

Spotlight on Chartered Practices in the area

Cover photo © Richard Fraser The Garden Building, at King’s College. Comprising student accommodation and situated on Cranmer Road, it was designed by Allies and Morrison Architects to Passivhaus standards. The CAA thanks the Bursar’s Office at King’s College for assistance and guidance in enabling the cover shoot to take place.

The CAA thanks the following sponsors AC Architects Cambridge Ltd Archangel Architects Bassett Architects BCR Infinity Architects BFA Architects Cowper Griffith Architects EIKON Architecture and Design Ellis Miller + Partners Emma Adams Architect

Fawcett and Haigh George Davidson Architect Graham Handley Architects M Reynolds RIBA Mart Barrass Architect Ltd Mole Architects N J Twitchett Neale Associates NP Architects Peter Rawlings Architects Ltd

R H Partnership Architects Ltd Simon Blackburn RIBA studio24 architects

CA81 was supported by a generous donation from the Cambridge Forum for the Construction Industry and made possible with funds from the RIBA East Local Initiative Fund

Cambridge Architecture 3

News and events

News

2021 CAA Committee elections Following the recent (virtually held) AGM in February 2021, the Cambridge Association of Architects is pleased to announce its committee members for the current session, including a new Chair, Mart Barrass, of Mart Barrass Architect Ltd. Mart takes over from previous

The 2021 committee consists of: Chair: Mart Barrass (Mart Barrass Architect Ltd) Secretary: Quratulain Hafeez (freelance) Treasurer: Kelly O’Doherty (BCR Infinity Architects) Communications: Mark Richards (studio24 architects) Data Champion: Tom Foggin (R H Partnership Architects) Outreach: Ann Bassett (Bassett Architects) Events Coordinator: Looking for a volunteer! Sustainability Champion: Alice Hamlin (Mole Architects) Fundraising: Marie-Luise Critchley-Waring

The editors

4 Cambridge Architecture

Welcome As we write this, the nation is enacting Step 2 on the roadmap out of lockdown – and, as we go to press, we should be passing Step 3. It has been a difficult year, but the CAA would like to thank its readership and community for their continued support and encouragement. Among the features in this issue, Alex Reeve unveils the new headquarters for the University of Cambridge Institute for Sustainability Leadership; the Secret Architect returns with some commentary on Park Street Car Park; Nicola Carniato discusses the circular economy; Janet Hall helps explain how Swaffham Prior is gaining a sustainable heating network; and Margaret Reynolds discusses the ethics of retrofit. Reassuringly, it is also awards season, and we take great pleasure in showing the winners of the Cambridge Design and Construction Awards 2021, along with our regular feature showcasing local projects under way. You will also notice some extended descriptions of some of our sponsors. If you’re a sponsor and want to be featured, please send us some text and images and we’ll be glad to show the readership your best side. The past year has shown that, if nothing else, we need to continue to rethink how we approach building design and construction – encouraging our clients to think ahead, considering how a project can minimise the environmental impact and create flexible, sustainable spaces that can support them for the long term.

Chair Rachael Branton. New for this year is the post of Sustainability Champion, led by Alice Hamlin and following on the successes of the recent sustainability lectures. If you want to add your name to this illustrious list, please email chair@cambridgearchitects.org

A new garden in the oldest college Suffolk-based, award-winning garden designer Tom Hoblyn has designed a new garden for Peterhouse, Cambridge. Known as Cosin Court, the intent for the three-acre plot is to create a series of accessible, inviting gardens with a focus on health and

wellbeing, and pioneering a sustainable way to treat these historic spaces. Hobson’s Conduit forms part of the inspiration behind Hoblyn’s Cosin Court water feature, which will capture rainwater for irrigation, but also provide a calming influence over the garden.

News and events

Transforming Nottingham Castle Purcell has recently completed the transformation of Nottingham Castle museum and art gallery, a Grade I listed Scheduled Monument. Works included the repair and refurbishment of the C17 Ducal Palace and medieval Gatehouse, improving access to the historic caves, and a new, contemporary visitor centre set within a remodelled landscape.

MCW wins consent for St John’s College project community to meet, eat, drink and work in an inviting and relaxed atmosphere. A ‘fabric first approach’ aims to protect the integrity, stability and condition of historic fabric, minimising potential harm while supporting the commitment to energy efficiency and carbon reduction.

Planning and listed building consent has been granted for a new refurbishment project at St John’s College, with a team comprising MCW Architects, Turley Planning Consultants, Purcell, Tobit Curteis Associates and KJ Tait. It will provide a place for the whole college

CAA past and present The CAA is collecting information on the history of the organisation, to be shown on the website and in future editions of Cambridge Architecture. As a volunteer association, records can sometimes be patchy, so we’re interested in your knowledge of the CAA’s history, in particular the 1950s: who was running the organisation, and what were the major issues of the day? Send your historical knowledge to editors@ cambridgearchitects.org

Add your story to the online archive In retirement, Alex Reid, former chair of the CAA and former Director General at the RIBA, produces an online archive of life stories, called Lives Retold (www.livesretold.co.uk). If any CAA members have written an account of their life, or are minded to do so, Alex would be very pleased to hear from them. He can be contacted at aalreid@gmail.com

Plan for Use First homes unveiled at Inholm The first homes have been craned into position at Inholm, Northstowe. The project, by developer Urban Splash, will deliver 406 houses constructed using MMC (Modern Methods of Construction), which will use approximately 67% less energy to build, compared with traditional builds.

Customers can select internal layouts, and the house is then precision built in the factory, fitted with bathrooms and kitchens, before being delivered in sections and constructed on site in just a few days. The houses combine high levels of insulation, energy-saving components, and qualitycontrol standards.

A building’s life begins at handover, though we often consider that as nearing the end of our appointment. This needs to be reversed, and the RIBA’s latest publication, Plan for Use, details the processes and best practice for postoccupancy evaluation, which starts at a project’s inception. www.architecture.com/ knowledge-and-resources/resourceslanding-page/plan-for-use-guide

Cambridge Architecture 5

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CISL retrofit

Leading the (ex)change © Soren Kristensen Entopia Building exterior

As the UK prepares to host the COP26 conference of parties to the UN Convention on Climate Change, there are some big questions the nation’s construction industry is having to address WORDS ALEX REEVE, WENDY BISHOP AND LUCY TOWNSEND

A project is now under way in Cambridge that should help provide answers to some crucial questions. Can renewable energy capacity expand fast enough to meet our heating demands? How can we limit the carbon impact from construction materials? Can we adapt our existing buildings to fulfil our needs and promote our wellbeing over the long term? The aim is to create a visionary new headquarters for the University of Cambridge Institute for Sustainability Leadership (CISL). It will be known as the Entopia Building and involves retrofitting a 1930s former telephone exchange at 1 Regent Street, Cambridge. As well as CISL’s Cambridge-based staff, the building will house a sustainability hub and accelerator supporting small businesses and start-ups.

Background

The overall project budget is £12.8m, made possible by a £6m donation from greentech leaders Envision Group and a £3m grant from the European Regional Development Fund, which is also funding the operation of the sustainability hub and start-up accelerator for three years. This will foster collaboration, capacity building and knowledge transfer between industry experts,

researchers, and major companies. The University has also invested its own funds in the project alongside an internal grant from its Energy and Carbon Reduction Project. The building name references the Entopia concept developed by Envision to shape a future where access to clean, secure and affordable energy is available to all.

Brief

The project intent is to be a world-leading exemplar of sustainable retrofit. This is reflected in a brief developed by CISL Fellow Professor John French, who previously led the design and build of the award-winning Enterprise Centre at the University of East Anglia, demonstrably one of the most sustainable office buildings in the UK.

Key targets include: No fossil natural gas Passivhaus standard for refurbishment (known as EnerPHit) Highest possible BREEAM environmental assessment rating of 'Outstanding' Embodied carbon at less than 300Kg CO2/ m2 over 100-year life of the building Project to form a case study for promoting the circular economy 70% of material used to be biobased Soft Landings and post-occupancy evaluation to enhance performance and provide feedback Project to be replicable Health and wellbeing to be promoted by achieving WELL Gold certification

Saving CO2 emissions embodied in the construction process

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CISL retrofit

Wendy Bishop, architect at Architype, writes basement retaining walls are also being insulated, with some complex detailing to ensure continuity of the insulation line, and to minimise heat loss through thermal bridges. The non-original, single-glazed sash windows are being replaced by Passivhaus-certified tripleglazed windows, with the frame sitting in line with the internal insulation and recessed behind the existing structural opening. Designed to maximise energy performance and daylighting, it offers the optimum internal environment solution. The window change caused debate with planners because of the historic context, but the energy efficiency and daylighting benefits, as well as the impact on wholelife carbon (operational carbon savings dwarfed the extra embodied carbon associated with extra glass) proved persuasive to the planning committee.

Architype has used ECCOlab software to analyse embodied carbon. The initial target of 300kg CO2e/m2 over a 100-year life was ambitious and the modelling is under review. The client’s brief to maximise natural bio-based materials overlaps with minimising embodied carbon, and timber, cork and sprayed cellulose acoustic insulation to soffits have been used where appropriate, although the team has been cautious of adding extra material if not needed. The contractor (ISG) has been able to identify lots of opportunities for sourcing reused materials, so the completed building can demonstrate the principles of the circular economy through extending the life of the building structure, as well as with the reuse of light fittings, reclaimed steel sections, recycled paint, and repurposed furniture, among others. © Architype_Window study

The building’s existing fabric is being enhanced to meet the EnerPHit criteria of less than 25 kWh/m2 per annum heating demand, and an airtightness of less than 1 air change per hour at 50Pa. As well as exemplary energy efficiency, the EnerPHit and WELL standard offer considerable air quality, health and wellbeing benefits. The solid masonry walls are being insulated internally, as the building lies within Cambridge’s central conservation area. Following design development, a thin layer of Diathonite (an insulating plaster using natural cork) is being used on the existing walls, preventing moisture being trapped within the wall construction, as well as providing an effective airtightness layer. This is followed by wood-fibre based insulation and the internal finish. Roofs, the lowest floor slab, and the

3D view – existing window bay The current windows are neo-Georgian sliding sashes with thick frames. Unlike traditional elegant Georgian windows, the current windows appear heavy and impact on daylighting within the building.

Elevation – existing window bay

second

first

ground

basement

3D view – proposed window bay The proposed triple-glazed windows sit behind the existing wall line, concealing the window frames from the outside. This maximises daylight within the building as well as giving a contemporary appearance, differentiating the new windows from the existing building fabric. The structural reveals are lined with a slender window surround which will reflect daylight to further maximise light within the building.

Elevation – proposed window bay

Exploring sustainable window design

Smith and Wallwork Ltd 50 St Andrews Street, Cambridge, CB2 3AH www.smithandwallwork.com 01223 750 249 contact@smithandwallwork.com 8 Cambridge Architecture

Lucy Townsend, sustainability associate at BDP, writes

Energy Efficiency Passive Design Air Quality Thermal Comfort Commissioning Materials Amenities

Circadian Lighting

Active Travel

Drinking Water

Visual Comfort

Responsible Food Ergonomic + Active Furnishing Restorative Spaces

Lighting Water Conservation Site Selection

Access to Nature

Acoustics

Community

Waste

Nutritional Standards

Consultation

New Parent Support

Flood Risk Light Pollution Noise Pollution

Material Reuse/Recycling

BIO-BASED MATERIAL

Lifecycle Carbon

Protecting Ecology Impact of Refrigerants Adaptation to Climate Change

EMBODIED CARBON

POE

(VAV) mechanical control dampers, linked to room temperature and CO2 sensors. Although active cooling is via the AHU's integrated heat pump and supplementary FCUs, these are modestly sized. The building has not been designed to supply full air conditioning to maintain temperatures at 21°C, instead a peak lop strategy is deployed in conjunction with other passive measures; such as using the buildings exposed ceiling soffits for thermal mass, nightpurge ventilation and natural ventilation via openable windows. Because of the relatively small domestic hotwater demand the project will use electric showers, and a mix of instantaneous and point-of-use water heaters for basins and sinks, respectively. This aligned with the project aspiration to do away with mains gas, and going to an all-electric building. A rooftop photovoltaic canopy will offset some of the demand. Entopia is on track to gain world-leading sustainability and wellbeing certification from BREEAM (Outstanding) and the WELL Building Standard (Gold), demonstrating how an existing office building can be made highly energy efficient in its redevelopment and use, while supporting the enhanced wellbeing of staff and visitors. The project is also applying ‘circular economy’ principles to minimise the volume and impact of resources used in the building. A practical example of this involves the contractor (ISG) sourcing existing lighting from another building refurbishment that has involved the re-testing and the re-issuing of warranties of more than 350 LED lights. Electricity (KWh/m2 GIA /yr)

Pre-refurbishment based on 2017 and 2018 utility bills

223

140

Prediction

Zero

57.5

Faithful+Gould

Security

Durability CIRCULAR Material Optimisation ECONOMY Functional Adaptability

Intersections between the sustainability standards targeted

Gas (KWh/m2 GIA /yr)

@fgouldconnect

Whole Life Costing Safety

Mental & Physical Health

Energy consumption

www.fgould.com

Responsible Construction

World leading project and programme management consultancy

Conventional retrofits tend to focus on isolated system upgrades (in other words, lighting, windows or HVAC equipment). These retrofits are generally quick and simple, but often miss opportunities for larger and more cost-effective energy savings, increased comfort and durability. Deep energy retrofits achieve much greater energy efficiency by taking a whole-building approach, addressing many systems at once. For buildings with particularly poor energy performance, with multiple systems nearing the end of useful life, the most convenient and economical approach can be to upgrade everything at once. When Entopia is completed, it will provide estimated annual energy savings of up to 80% a year when compared with the existing baseline energy use (calculated using utilities meter readings consumption). An Energy Performance Certificate of ‘E’ is expected to become an ‘A’. The heating strategy for the building is based on fabric first principles that have become synonymous with the Passivhaus standard. A wellinsulated, airtight approach is used to reduce heat demand, meaning a small-scale, all-air system can be used effectively. The primary heating and cooling to the building is provided via the central ventilation systems air handling unit (AHU), which is fitted with an integral reverse cycle heat pump that operates in heating or cooling modes. This type of all air system on a smaller scale is really only possible when utilised in conjunction with the exacting fabric efficiency measures and quality assurance required by the Passivhaus/EnerPHit Standards. Secondary heating and cooling is provided in the form of electric panel radiators and variable refrigerant flow fan coil units (FCUs). This offers some additional control trimming or supplementary cooling when required, though generally limited to cellular offices, meeting spaces and designated conference spaces. Demand-control ventilation is used for an element of zonal control, while optimising the individual flowrates required for each space and this ultimately leads to a reduction in fan power and energy consumption. The central ventilation AHU is operated and controlled by variable air volume

CISL retrofit

Providing leadership

A key question will be how replicable various aspects of the project will be? To help promote this, CISL and the University’s Estates Division will be working to provide detailed case-study information on energy, material choices, and health and wellbeing targets as works progress. Keep an eye out for articles in the trade journals and on the CISL website: https://www.cisl.cam.ac.uk/about/ entopia-building

Key members of the project team Primary funder: Envision Group Co-funder: European Regional Development Fund Co-funder and building owner: University of Cambridge Primary user: Cambridge Institute for Sustainability Leadership Architect: Architype Buildings Services Consultant: BDP Project Manager: 3PM Cost Manager: Gardiner & Theobold Passivhaus Consultant: Mead Consulting BREEAM & WELL Assessment: BDP Main Contractor: ISG

Cost Management

Building Surveying

Programme Management

Health & Safety Services

Project Management

Sustainability

Project Controls

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Retrofit PAS 2035

Roadmap to retrofit As retrofit gains recognition as a key aspect of the climate challenge, there will be greater demand for skilled designers supporting clients to make informed decisions following recognised processes

WORDS PATRICK OSBORNE

Example options appraisal for retrofit, ranging from light-touch (Scenario A) to deep retrofit (Scenario C), illustrating potential timing of works as part of a medium-term retrofit plan. Taken from Targeting Zero: Embodied and Whole Life Carbon Explained by Simon Sturgis, available from the RIBA Books: http://bit.ly/ca81targetzero While we have seen huge improvements to the carbon intensity of the electric grid over the past decade, our homes have seen little change in how much energy they consume. Currently, the domestic housing stock accounts for 18% of the UK’s total annual carbon emissions, and while the decarbonisation of the grid will help, predictions suggest we need to comprehensively retrofit more than 20 million homes by 2050. Retrofit also provides opportunities such as reduced fuel poverty and utility bills as well as improved indoor air quality and thermal comfort. As our summers become hotter, retrofit can also be designed to reduce overheating. You may have come across PAS 2030:2019 if you have read about the recent Green Homes Grant scheme, the latest in a string of funding

For more information on the PAS 2035 retrofit coordinator role: https://bit.ly/2R37V3C Eastern New Energy: https://bit.ly/3xo7d1R Retrofit Academy training: https://bit.ly/3gEEWhr AECB CarbonLite course: https://bit.ly/3sRcQ55

mechanisms for domestic retrofit. This document sets the standard for the completion of retrofit, managed by the government-endorsed quality assurance scheme, Trustmark. PAS 2035:2019 is the parallel standard that sets out the process for assessing, evaluating, and planning for how dwellings are retrofitted. It defines several new roles, with the retrofit coordinator and retrofit designer being the most relevant to practising architects. The standard sets out a process of risk management using a ‘whole-house approach’ and using ‘medium-term retrofit plans’ that give a client a roadmap to phasing retrofit up to 2050 with works, and their potential benefits, identified in sequence.

Qualifying as a retrofit coordinator or designer

Currently, there are two routes to qualify as a PAS2035-accredited retrofit coordinator: the first through the Retrofit Academy, currently running 12 online modules with an optional two-day ‘boot camp’. The alternative is by completing the AECB CarbonLite course with an additional module focused on the PAS processes. Architects can act as a retrofit designer for most projects, however for traditionally constructed buildings or those deemed to be higher risk – for instance, ‘protected’ buildings (listed or conservation

area), or those where multiple measures are installed – designers with additional qualifications would be required. These include those who are on the AABC (Architects Accredited in Building Conservation) register; have a level 3 award for Energy Efficiency and Retrofit of Traditional Buildings; or have also completed the retrofit coordinator training.

Opportunities and future work

LETI (London Energy Transition Initiative) is due to publish a guide to domestic retrofit soon, which will detail the latest research into how far we need to retrofit to meet our climate targets. A new standard in the series, PAS 2038, focused on non-domestic buildings, is due for publication this summer. As retrofit becomes more widely recognised as critical to tackling the climate challenge, architects with accreditation in the processes for assessing their existing properties and planning appropriate retrofit will be well placed to support clients seeking advice to make informed decisions. Three initiatives are already running with retrofit coordinators and designers: Cosy Homes Oxfordshire; Warmer Sussex; and Eastern New Energy for Cambridgeshire. Patrick Osborne is an associate and sustainability lead at R H Partnership Architects and a PAS 2035-accredited retrofit coordinator.

Cambridge Architecture 11

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Circular economy

Designing out waste The restriction on movement of people and goods caused by the Covid-19 pandemic has exposed the global supply chain to one of the most significant challenges since the birth of globalisation. How could a circular economy help? WORDS NICOLA CARNIATO, TECHNICAL DIRECTOR AT AKT II

he pandemic is not a short-term crisis; it will have long-lasting implications for how people work and how supply chains function. At a time when the climate emergency is bringing into sharp focus the fact that we cannot continue building as we always have, there is an urgent need for businesses to improve the resilience of their supply chains in preparation for future challenges. More importantly, the current crises have highlighted the need for a critical reassessment of the present global economic model. The existing, linear economic system offers traditional linear consumption patterns of ‘take make dispose’, which increase the exposure of companies to risks such as higher resource prices and supply disruption, and are causing environmental degradation, climate change, biodiversity loss, and pollution.

Design Out Waste

A circular economy will provide a sustainable economic model that is founded on a resilient supply chain and on environmentally focused outcomes. It will also offer opportunities for innovation and creativity to enable this positive, restorative economy. A circular economy replaces the concept of ‘end of life’ with the concept of restoration, and aims to eliminate waste through lasting and nourishing design.

Catalysing opportunities

Aim for Less

In the face of supply disruptions and higher resource prices, the call for the adoption of a circular economy is becoming louder. Brexit – and the potential difficulties in transporting materials across borders – could catalyse opportunities for the UK manufacturing industry to secure these material supplies from a stable domestic market, and could stimulate the materials’ circular flow. Around 400 million tonnes of material are used by the UK construction industry each year, of which approximately onequarter is imported, with some sectors more reliant on imports than others. Almost 70% of timber, for example, is brought in from overseas using carbonintensive sea freight. Yet, with around 100 million tonnes of material wasted each year, the construction industry is

Cambridge Architecture 13

Circular economy

responsible for more than 50% of all of the UK’s waste. These numbers, together with resource scarcity and dramatic rises in the cost of raw material – coupled with the cost of waste disposal – are directing businesses to think of this waste as a valuable resource that can be exploited by adopting more-circular business models: one industry’s waste becomes another’s raw material.

concern that future development, which comes with growth, will harm the natural environment and the ecosystem services.

Economic recovery

Sainsbury Laboratory: the building was appropriately located within its sensitive landscape. The internal layout allows connectivity among the scientists

Butterfield Innovation Centre: an award-winning business park with sustainability in mind

The circular economy offers a solution, decoupling economic growth from resource use and environmental impact, and can shape a pathway towards a more resilient, low-carbon economic recovery. Alongside material resourcing, circular-design thinking also promotes the benefits of renovating and upgrading existing buildings over demolition, including through a holistic repurposing where appropriate. These renovation projects must increase durability, by selecting long-lasting materials and by considering adaptability and energy efficiency. When all options are exhausted, and once it’s been demonstrated that a building’s retention is not feasible, a pre-demolition audit should be undertaken to identify assets and materials that can be taken out,

Environmental challenges

Cambridgeshire has experienced a constant growth in population over recent years, with the planning of sustainable expansion across the Oxford-Cambridge Arc set by the Arc Spatial Framework in February. The built-environment industry is under pressure to deliver affordable, high-quality housing, alongside good, suitable working space and other facilities, and to provide clean, green infrastructure without exacerbating climate breakdown or air pollution. Cambridge sits at the confluence of two important growth corridors – the East-West Arc and the UK Innovation Corridor – but also faces unprecedented environmental challenges, as outlined in the council’s biodiversity emergency declaration almost two years ago. Cambridgeshire and Peterborough combined have one of England’s lowest percentages of land designated as either priority habitat, natural green space or a nature conservation site. Only 6.5% of the land’s surface has statutory or nonstatutory nature-conservation designations, and only around 8.5% is ‘priority habitat’. Local air pollution is also much higher than the national average, so there is a

recovered, and where possible reused. For new buildings, the designs must be future-proofed to adapt to the needs of future generations, differing uses and climate change. Designs should demonstrate how the buildings will be maintained over the long term, so that any major renewals – such as façade replacements – will not adversely impact the occupants. The designs should also

Recovery of the construction materials

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Circular economy

Material Passport

show how the various layers of the development are to be cost-effectively disassembled, to support the recovery and reuse of the building’s systems, components and parts, as and when these need replacing. The application of circular principles to the design of buildings provides a pathway towards net zero, by specifying materials with low environmental impacts, while also ensuring the optimisation of performance parameters and the consideration of endof-life scenarios.

Shrewsbury Flax Mill is a complex restoration of Grade I, II- and II* listed buildings to provide mixed-use facilities

Design control

Some materials are inherently more carbon efficient than others, but all materials can be specified to deliver better (or worse) carbon impacts. As designers, we must

Fourth Age

control this. The impact of concrete, for example, can be mitigated with the use of cement replacements such as GGBS (a by-product of the production of steel) and with locally sourced or recycled aggregates. Novel mixes, consisting of alkali-activated materials (AAMs) and geopolymers, can also replace the cement, to provide lower-carbon concretes. Steel is fully recyclable and can be reprocessed in an electric arc-furnace that is powered by renewable energy. It can also, however, be re-used if not damaged, the obstacles of which are currently within the certification process for reconditioning the steel members. Timber, in many ways, may be considered the ultimate circulareconomy resource, and the ultimate renewable resource – but only if procured

from forests that are sustainably harvested, and if the structural members are designed for reuse and remanufacture. The circular economy fosters collaboration and innovation towards sustainability goals, thereby increasing productivity and creating new jobs. Collaboration with suppliers and designers can keep used products, components and materials in circulation, while digitalisation can boost this process with solutions such as the ‘material passport’. This gives materials value for recovery and reuse, and can be based on building information modelling (BIM). This attitude offers the possibility to bounce forwards from this period, by placing the three ‘Ps’ – planet, people and profit – at the centre of growth strategy.

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CDCA Awards

Cambridge Design and Construction Awards The Cambridge Forum for the Construction Industry (CFCI) and the Greater Cambridge Shared Planning Service recently announced the winners of the Cambridge Design and Construction Awards for 2021, celebrating the best construction projects completed in the city within the past five years. The judging criteria for 2020/21 included: the context and the brief for the building; the design solution adopted; and

the quality and difficulty of the construction and craftsmanship displayed in the building. Accessibility and the creation of an inclusive environment were also key considerations. Each scheme is expected to address environmental concerns, including energy performance, and, where possible, expected to make a contribution to the natural environment, both on the building and in the landscape around the building.

Best New Building (over £2m construction cost)

Chemistry of Health, Department of Chemistry, University of Cambridge Client – University of Cambridge Main contractor – Kier Construction Architect – R H Partnership Architects Services consultant – K J Tait Services contractor – Kershaw Mechanical Services Structural engineer – Ramboll UK Project management – 3PM Quantity surveyor – Aecom ‘A moment of joy, and a building of architectural merit on a difficult site, responding well to the context, resolving circulation problems within and between the existing buildings, and with a clever internal organisation and circulation.’

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16 Cambridge Architecture

Client – Bursar and Fellows of King’s College Main contractor – RG Carter Architect – Allies and Morrison Structural engineer – Smith and Wallwork Services engineer and Passivhaus designer – Max Fordham Passivhaus certifier – WARM Landscape architect – LDA Design Cost consultant – Faithful and Gould ‘The first major Passivhaus scheme in Cambridge. This group of low-energy buildings works well within the context of the existing Edwardian red-brick villas in the conservation area… an exceptional building with good materials and a high environmental aspiration, which will inspire others to follow.’ © Nick Guttridge

Cranmer Road Student Housing, King’s College

CDCA Awards

Best Building: Conservation, Alteration or Extension (under £2m construction cost)

10 Portugal Place Client – Private owner Contractor – RM Construction Architect – Haysom Ward Miller Structural engineer – George Voyias ‘[It was an] inspirational move to remodel the centre of the plan with a new oak staircase and landings, allowing light to penetrate into the ground floor and basement, and opening up views to the tiny courtyard garden… transforming the interior into a wonderful living space.’

Bodley Court, King’s College Client – Bursar and Fellows of King’s College Contractor – RG Carter Conservation architect – Donald Insall Associates Services engineer – Hoare Lea Project manager and quantity surveyor – PM and QS Services ‘A fantastic example of conservation and repair with forward vision, tackling the most urgent and difficult problems first while looking to continue the refurbishment of the building interiors in the future.’

Best Building: Conservation, Alteration or Extension (over £2m construction cost)

Sustainability and Engineering Award

Best Building: Conservation, Alteration or Extension (over £2m construction cost)

Cranmer Road Student Housing, King’s College

Client – Bursar and Fellows of King’s College Main contractor – RG Carter Architect – Allies and Morrison Structural engineer – Smith and Wallwork Services engineer and Passivhaus designer – Max Fordham Passivhaus certifier – WARM Landscape architect – LDA Design Cost consultant – Faithful and Gould ‘The overall environmental performance of the building, including embodied energy, selection of natural materials and embodied carbon, was considered to be exemplary, and the scheme delivered improved biodiversity in the remodelling of the landscape and gardens.’

The Old Granary and Counting House, Darwin College Client – Darwin College Main contractor – Messenger Conservation architect – Allies and Morrison Structural engineer – CAR Services engineer – Max Fordham Interior design – Eve Waldron Design Landscape architect – Bradley-Hole Schoenaich Cost consultants – DR Nolan and Co ‘The internal remodelling dealt with low tie beams passing through rooms and upgrading the poor condition of the building fabric. The judges praised “the sensitive resolution of these difficulties while maintaining and improving the internal character to make it a delightful place to live and work”.’

Excellence in Engineering Cambridge Architecture 17

CDCA Awards

Congratulations also go to the following commended projects:

Craftsmanship Award

10 Portugal Place

Conservation, Alteration or Extension commendations: The Copper House, by Butcher Bayley Architects Seeley Library, for the University of Cambridge, by R H Partnership Architects Vinery Mews, by PiP Architecture MCR The Grove, for Fitzwilliam College, by R H Partnership Architects New Building commendations: 50-60 Station Road, by Grimshaw Architects Key Worker Housing, Eddington, for the University of Cambridge, by Mecanoo Sustainability and Engineering commendation: Vinery Mews, by PiP Architecture

Client – Private owner Contractor – RM Construction Joinery contractor – Maple Joinery, of Royston ‘The award is given for the general quality of the main contractor works and for the quality of the joinery in particular, carried out by Maple Joinery, of Royston.’

Craftsmanship Award

Bodley Court, King’s College

Client – Bursar and Fellows of King’s College Specialist roofing contractor – Claude N Smith Specialist stonemasonry – Hibbitt and Sons ‘The award is given for the Collyweston roofing works, undertaken by Claude N Smith, and the stonework repairs and conservation by Hibbitt and Sons.’

Craftsmanship Award

The Old Granary and Counting House, Darwin College Client – Darwin College Contractor – Messenger Plastering subcontractors – RD Alsop Joinery – Mitchell and Hudson Fireplace restoration – Alexandra Carrington Conservator ACR Conservation of wall paintings – Tobit Curteis Associates ‘The award is given for the overall conservation works undertaken by Messenger, as main contractor, with its own skilled labour force and specialist subcontractors, and for the conservation of the Gwen Raverat wall paintings.’

Cambridge Architecture 19

Ethics of retrofit

‘Clean, secure and affordable energy… available to all’ 1

Alongside sustainable new development, something must be done with the vast majority of buildings already standing, which people will still be occupying in 2050. While ‘eco-retrofit’ exemplar projects can be impressive, are there other ways to tackle the climate crisis without breaking the bank? WORDS MARGARET REYNOLDS

‘L

ife is unfair,’ declared economist Milton Friedman. So it is with income – and with buildings. Many in this country are saddled with leaky, hard-to-heat or overheated premises, when we know it is possible to construct and renovate buildings to be comfortable and use minimal energy. ‘Retrofit’ is the term increasingly used for overhauling building fabric, ventilation, heating and electrical systems to reduce energy usage and the resultant carbon emissions. However, the present reality for clients who would like to eco-retrofit their property is the paucity of advice, funding and construction expertise that is available. Yet, building retrofit is absolutely critical for our future: ‘Do we really need to build, do we really need to put more carbon into construction, or can we upgrade our buildings?’ asks Peter Clegg, founding signatory of Architects Declare.2

An urgent need for retrofit

Downing Place United Reformed Church insulated roof and daylighting on the new mezzanine

Construction has evolved empirically, by repeating what has worked in the past, but now we need it to absorb new research and technologies quickly. Remember the Green Deal in 2013? That was all about reducing the fuel used for heating, and cutting our utility bills in the process; Green Homes Grants were another problematic attempt. The goalposts keep moving; we are facing mass extinctions; the climate

emergency demands massive cuts in carbon emissions; and the UK government target is to decarbonise energy for buildings and transport by 2030.3 An excellent new tool for implementing this reduction is Publicly Available Specification (PAS) 2035, which calculates the impact of retrofit, and safeguards clients’ interests and the quality of work (see page 11). PAS 2035 Improvement Option Evaluations shows that some building geometries and retrofit designs achieve energy reductions more easily than others; some retrofit measures emerge as carbon neutral or better. PAS 2035 Medium-Term Improvement Plans indicate phasing opportunities and allow for future techniques and inventions. This analysis allows us to face squarely the inevitable repositioning of retrofit goalposts. Of the 44 measures evaluated, 11 involve costly fabric insulation, but 23 are ventilation-heating or heat sources, and five are renewables. Not everything requires the six-figure construction costs of fabric measures, however important these are for increasing efficiency. Does our usual fabric-first priority make sense in an emergency? Swapping gas heating for a heat pump can be minimally invasive and virtually eliminate emissions from fossil fuels. This is a real game-changer. With a heat pump, it is logical to seek off-peak, lower-carbon grid electricity at time-of-use tariffs, to generate power on the premises, and to store both these sources of energy in batteries. This points sensibly to a home energy system linked to an electric vehicle charger. Because the equipment bolts on, and supplier deals change, the kit can be easily accessed and updated as technologies evolve, rather than physically altering the building fabric. We designers need to do continual research, leaving no stone unturned, yet hedging our bets. We need to prescribe retrofit procedures that can nimbly incorporate the inevitable changes of standards and technology as soon as they are proved.

How can we keep informed of the latest retrofit thinking?

Check out the achievements in Ireland under the Sustainable Energy Authority of Ireland (SEAI) in Passive House Plus magazine.4 If the work is overseen by a qualified project coordinator, 35%-40% of home retrofit costs are funded.

Manufacturers of the highest quality timber windows, doors, bespoke cabinet works and supplier of high performance aluminium doors and windows. 20 Cambridge Architecture

Ethics of retrofit

New rooflights, solar shading and solar photovoltaics on the insulated roof at Downing Place United Reformed Church

Because equipment bolts on, kit can be easily accessed and updated as technologies evolve, rather than physically altering the building fabric

How should we advise clients seeking deep eco-retrofit?

References 1 www.cisl.cam.ac.uk/news/news-items/entopiabuilding 2 CFCI Cambridge Climate Emergency Month webinar – bit.ly/ca81declare 3 BEIS, The UK’s Nationally Determined Contribution under the Paris Agreement, BEIS, 12 December 2020, www.gov.uk/government/ publications/the-uks-nationally-determinedcontribution-communication-to-the-unfccc 4 Subscription included in AECB membership: www.aecb.net/benefits-of-aecb-membership 5 openecohomes.org/eco-homes-archive 6 www.cisl.cam.ac.uk/news/news-items/entopiabuilding 7 Archangel Architects www.archangelarchitects. co.uk/work/downing-place-united-reformedchurch-cambridge and CFCI Downing Place URC webinar – bit.ly/ca81downing 8 www.aecb.net/product/carbonlite-retrofittraining 9 www.retrofitacademy.org/coe

External wall insulation may be suitable for some projects, but can require costly extension of roof eaves and verges, and drainage

Swapping gas heating for a heat pump can be minimally invasive and virtually eliminate emissions from fossil fuels

Climate-activist owners who self-fund projects can show the way. Such projects boost expertise in the retrofit ‘market’ locally, generate publicity for procedures, the supply chain and contractors, and offer friendly access to their personal experience. Similarly, with solar photovoltaic (PV) panels in 2010: ‘the rich’ with capital were offered high feed-intariff rates (extracted from all utility company customers) for expensive early installations. In the long run, however, this created a PV market with prices that were a third of the cost, benefiting everyone. Designers wishing to develop their skills in retrofit have a number of options, including the six-month Association for

Energy Conscious Building (AECB) CarbonLite course8 and courses by the Retrofit Academy.9 The AECB also offers retrofit coordinator training and Passive House Planning Package (PHPP) energy modelling. In addition to design, we also need more skilled retrofit contractors. Few builders are ready to take on the costs in time and money of acquiring the necessary PAS credentials. Fortunately, funded retrofit training for builders is now firmly on the agenda of the Retrofit Academy. So, watch this space. Margaret Reynolds is an architect and retrofit coordinator, with experience of retrofit and residential projects across Cambridge. She is a member of the AECB and was energy adviser for the Downing Place United Reformed Church project.

To estimate costs of retrofit measures, take a look at more than 50 homes available in our local Open Eco Homes (OEH) archive.5 Where disclosed in the OEH archive, overall retrofit costs run from £70,000 (DIY) to £280,000 (with a two-storey extension). Projects range from new architect-designed houses to DIY insulation work. Also included are three non-domestic buildings, and one narrowboat! Some OEH retrofit projects paid only 5% VAT for energysaving measures; some qualified for the government’s Renewable Heat Incentive (RHI, ends March 2022) for heat pumps – small, but useful, government subsidies. Clearly, all our buildings need retrofitting and yet, illogically, for nondomestic buildings the government rescinded the 5% VAT reduction in 2013, and the tiny RHI non-domestic subsidy now offered is hardly worth the time it takes to apply. Two large non-domestic retrofit projects in Cambridge city centre illustrate what can be done architecturally with interesting old buildings: As described in this issue, (see pages 7-9), the £12.8m retrofit of the Entopia Building (2,986m2, £4287/ m2) to Passivhaus EnerPHit standard; Architype, for the Cambridge Institute of Sustainable Leadership.6 The £3.4m retrofit of Downing Place United Reformed Church (990m2, £3,414/m2), funded by the sale of another city-centre property; Archangel Architects, completion April 2021.7

T: 01954 260 575 E:

Cambridge Architecture 21

Sponsors

In profile

Mart Barrass Architect (Ltd.) is a RIBA Chartered Practice based in Cambridge, established in 2010 to focus on the design of innovative, intelligent and sustainable habitats and community projects. Its work involves both new-build and complex listed properties, upgrading them for 21st-century living.

With experience mostly in domestic and educational architecture, Ann Bassett founded Bassett Architects in 2019. The practice enjoys the human and social element of building, from how a detail of a window or a connection to the outside can delight, to how a gathering space can initiate interaction and activity.

Bassett Architects

Peter Rawlings Architects Ltd

Peter Rawlings Architects Ltd undertakes a range of projects, from new houses and extensions to work for institutional clients. Peter is an architect accredited in building conservation, and many of his projects explore the interface between the historic environment and innovative new design.

BCR Infinity Architects

AC Architects Cambridge Ltd

After two years of successful collaboration, Barber Casanovas Ruffles Architects and Infinity Architects merged in 2018 to form BCR Infinity Architects. It offers more than 35 years of knowledge and experience in multiple sectors. Its aim is to achieve an appropriateness particular to each project that will fulfil the client’s brief, aspirations and community expectations.

rhp

rhp is an award-winning architectural practice, recognised for the breadth and depth of the skills it offers, from planning to energy efficiency, conservation to interior design, project management to project delivery. Established in Cambridge in 1974, rhp works both regionally and nationally.

Archangel Architects

Archangel is a practice with spirit, based in Cambridge since 2000. It specialises in supporting church and community building projects, creating affordable housing and inspiring Passivhaus eco-friendly homes.

Graham Handley Architects

Based in St Ives, Graham Handley Architects specialises in bespoke designs for residential and commercial projects. Its portfolio ranges from elegant contemporary designs that incorporate modern materials and stylish detailing, right through to listed or otherwise sensitive buildings constructed in complementary style and materials.

Established in 1997 by Anne Cooper, AC Architects is an award-winning practice combining innovative, quality designs with environmentally friendly, low-energy solutions. Its emphasis is on sustainability in all types of work, from new buildings and recycling buildings for a carbon-neutral future, to historic buildings and conservation work.

The publication of Cambridge Architecture would not be possible without the generous and consistent support of our sponsors. By way of thanks, in this edition we invited sponsors to share a little more about their work

Mart Barrass Architect (Ltd.)

From individuals to larger practices, every sponsor’s contribution to Cambridge Architecture is greatly valued. If you would like to find out more about our range of sponsorship options, please contact treasurer@cambridgearchitects.org

studio24 architects

studio24 has a particular interest in repurposing and remodelling buildings and urban renewal sites. Projects include house renovations addressing an increasing need for high-quality, design-led spaces that can accommodate a mix of family and individual interest, study and workspaces. The studio also collaborates with other like-minded architect practices to facilitate larger, mixed-use projects.

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Within the eastern region, our specialist Planning & Development team includes:

To find out more about our simply better advice, visit: carterjonas.co.uk/planning-and-development

Experienced Partners

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22 Cambridge Architecture

Dedicated professionals

Digital marketing

Social success At RIBA Guerrilla Tactics 2020, Susie Lober, of Lo Marketing, and Ayo Abbas, of Abbas Marketing, gave an introduction to digital marketing tactics WORDS SUSIE LOBER, LO MARKETING

#Tip1 – You don’t have to do everything Choose what works for you. Pick one channel and get that right first. Dedicate the time you can afford – for example, an hour a day, a day a month. Make use of scheduling tools. Make a plan for what you want to get out of digital and understand why you are there. It’s easy to fall in the digital black hole of scroll.

#Tip6 – Don’t stress about algorithms Algorithms are constantly changing. Create good content. Be consistent. Be useful. Quality is better than quantity; 100 engaged followers are more useful than 1,000 ambivalent ones. #Tip7 – Don’t ignore paid It’s not as easy as it once was to build an audience online. It’s worth seriously considering paid content. It doesn’t need to be expensive. #Tip8 – Own your data Thousands of followers on LinkedIn are great, but if it is shut down overnight, you’ve lost your contact list. Work on ways to build relationships offline. #Tip9 – Repurpose content People are busy, so you cannot assume they’ve

seen your social posts. Use a mix of evergreen and topical content. Update high-performing content and re-use. #Tip10 – Measure what you do What gets measured gets done. The best thing about digital marketing is it’s accountable. Use free tools such as Twitter Insights and Google Analytics. Regularly measure what you do and you can be confident in what works and what doesn’t. Remember, stick at it. Marketing is a marathon not a sprint.

A list of free digital marketing tools included in the Guerrilla Tactics talk can be downloaded at lomarketing.co.uk © Ridofranz, iStock

Digital marketing is the use of the internet – including websites, social media, search engines, email campaigns and online advertising – to reach customers. Before choosing the right digital tactics, you need a plan of who you want to speak to and what you want to say. If, for example, you want to attract residential extensions, your strategy will be different from a practice focused on school buildings, not just in terms of placement, but in terms of tone of voice and message. Digital marketing can be overwhelming, so here are 10 tips to get you started.

#Tip2 – Get your website working It all starts with your website. If you get work through referrals, the first thing anyone will do is look you up online. You have eight to 15 seconds to make a first impression. Revisit your website from your customers’ perspective. What do you want them to do? Create one clear call to action – for example, call me. #Tip3 – Search engine marketing This is how people find your website. It can be complex, but everyone can make an impact. Google promotes sites that are useful and easy to use, and penalises sites with poor page-loading speeds or out-of-date security certificates; both are easy to check. #Tip4 – Use a rich mix of content Use sketches, details, site visits, CPD and new materials, not just completed project photos. Don’t be afraid to show some personality. #Tip5 – Use video Video is a great way to show off your projects and who you are as a firm. It helps build trust, and the algorithms love it!

Cambridge Architecture 23

Swaffham Prior

The retrofit village A Cambridgeshire village is leading the way with a rural heat network that is powered by entirely renewable technology WORDS JANET HALL, LINEUNDRAWN

Project Board Council

he term ‘district heating’, typically prompts thoughts of large urban areas full of new homes that might only need heating on a frosty day. Suburban housing, rural villages and conservation areas, are unlikely to cross your mind. Yet, a village in East Cambridgeshire is set to change that: it leads the UK in delivering not just a rural heat network but one that is powered by entirely renewable technology. Swaffham Prior’s picturesque high street is lined by Grade II listed properties, a pub, school and two churches. The village has many house types, having undergone spurts of generational expansion over the past four decades. The latest phase, delivered five years ago by Swaffham Prior Community Land Trust

includes eight homes each fitted with air source heat pumps. It was this project that caused trust directors Emma Fletcher and Mike Barker to consider what a future without oil would look like for the village. What risks would the future pricing of oil pose to those on lower incomes? Could every household afford an air source heat pump, and is every house suitable?

Technical achievement

After two years of resident engagement, a heat network designed to work for every home is now just weeks away from construction. The renewable energy centre, to be located beyond the conservation area of the village in an agricultural barn, will contain a series of air source and ground source heat pumps connected to 130 boreholes. In winter, the ground source heat pumps will supply up to 1.5MW and in summer, the system

LEGAL EXPERTS IN THE GROWTH REGION 24 Cambridge Architecture

Swaffham Prior

a listed home and install an air source heat pump. The Green Homes Grant, enabled up to £10,000 (with conditions), is a tokenistic gesture to the costs involved in retrofitting a listed property (and has now been cancelled because of poor take-up). In the UK’s drive toward net-zero carbon by 2050, domestic heating is a contributor that can’t be ignored: it is responsible for around 15% of the country’s carbon emissions.

hitting UK oil prices, and perhaps then find yourself buying a green solution in an inflated market? It’s a question that many homeowners won’t even realise that they need to think about, but it’s one that the communal effort of Swaffham Prior has answered. The high-temperature system levels out the playing field so that all can have access to net-zero heating and maintain the incentive to reduce heating costs through energy efficiency improvements. Cambridgeshire County Council, Swaffham Prior Community Land Trust and the project team have worked with residents extensively, taking conversations in the village from ‘Why do we even have to do anything?’ to the fine technical, legal and financial detail of the project. This co-design process has resulted in an infrastructure that addresses the two-core project aims: to take the village off its oil dependency; and to address local fuel poverty. It is looking promising: over the past four months, the Swaffham Prior team has been contacted by more than 20 oilreliant villages throughout the UK, keen to achieve something similar.

Residents visiting the energy centre

More pressure

A ban on new homes connecting to the gas grid, and some European boiler manufacturers switching production from oil and gas, to hydrogen boilers or heat interface units, shows the direction of travel expected. With no timeline set out in law for our fossil-fuel exit, there is further pressure added to the homeowner’s decision: Do you leap now, before anything happens to oil prices and while some funding is available (the controlled exit)? Or do you wait, see what happens, hope that more grants come and no carbon-pricing is introduced

At Hewitsons when it comes to legal matters the client is the focus of everything we do.

Archaeological survey

Starting out The first steps for any parish council or community land trust should be to: Contact the local Energy Hub (https://www.energyhub.org.uk/) © LineUndrawn

switches to air source heat pumps for hot water supply. This dual-energy supply will guarantee temperatures outputs in the heating systems of up to 72°C, even in 0°C, giving residents a similar temperature output to a conventional gas or oil boiler. This technical achievement means that homes will be able to plug their existing central heating system into the 7km heat network running through the village. Among the 300 homes in Swaffham Prior, are 47 listed properties, the oil super-users of the village. Clunch walls, thatched roofs, limewash finishes and single-glazed windows; leaky buildings are commonplace. To help address this, a series of heat meters have been installed in a range of properties, houses from the 1700s, 1900s, and 1970s (live data is available to view at www. heatingswaffhamprior.co.uk). The older properties, regularly have a 15-20kWh heating demand during winter, that means a standard 24kWh oil boiler must work flat-out at its maximum efficiency of 85% (20.4kWh). An off-the-shelf individual air source heat pump, typically low temperature, up to 15kWh (100% efficiency) is, unfortunately, not going to be the instant answer for that older property. Triggering a property retrofit; more or bigger radiators, which may compromise the character of the property, sensitive insulation and draught exclusion to reduce the peak kWh requirement, an extra heat pump or supplementary heating may ultimately be required – which would also have planning consequences. All in all, a fine balancing act that requires a motivated homeowner and expert knowledge. With oil prices relatively low today, there is little financial incentive to retrofit

“The high-temperature system levels out the playing field so that all can have access to net-zero heating and maintain the incentive to reduce heating costs through energy efficiency improvements”

Enquire about the Rural Community Energy Fund (https://www. energyhub.org.uk/rural-communityenergy-fund/introduction/)

Absolute Client Focus.

Please contact Colin Jones on 01223 532 731 Cambridge Architecture 25

Park Street Car Park

The big question... In the context of the Climate Emergency declared by Cambridge City Council in February 2019, Cambridge Architecture asks whether the Park Street Car Park site is a prime candidate for leading by example with repair, retrofit and responsible reuse WORDS THE SECRET ARCHITECT / ILLUSTRATIONS ANDREW DRUMMOND

Park Street Car Park is scheduled for demolition. Its replacement will re-provide a reduced provision of car parking (-165 spaces), an increased provision of cycle parking (+70 spaces), a 200-bed Aparthotel, and a bee hotel.

The £90m new build will take four years to complete – the car park will open after two years followed by the above-ground hotel.

26 Cambridge Architecture

One of the primary benefits of redevelopment appears to be the creation of a £10m pot of money for offsite affordable city housing.

In the context of the council’s Climate Emergency declaration, what is the impact of rebuild, and what could an alternative retrofit deliver?

The existing four- to five-storey concrete frame contains about 3,245m3 of reinforced concrete.

An estimated 300 30-tonne tipper trucks will be filled, generating 600 vehicle movements through the city’s historic core.

When the existing frame is removed, the digging can start. A 10m-deep hole across the site will need to be excavated.

Filling 750 30-tonne tipper trucks, generating 1,500 more vehicle movements through the city.

If the demolished waste and spoil from excavation were combined, the resulting ‘hill’ could rival Castle Mound.

After three years, a new framework would be in place including 6,205m³ reinforced concrete. This equates to about 1,800 tonnes CO2.

The new frame requiring 775 fully loaded 8m³ concrete trucks arriving on site, generating 1,550 vehicle movements.

So, in some ways we’re back to the start with a concrete frame ready for fit-out, and another year of work to turn it into an Aparthotel.

Could we just inhabit the existing frame? What could it offer?

The existing structure offers 390 car spaces and 200 cycle spaces, public toilets and a small retail unit.

Reduce car parking and increase cycle spaces, erect prefabricated workspace on upper decks and crane 20-30 housing units on roof.

The views from the rooftop car park deck become the views from people’s homes.

The upper parking deck could offer a secure working space with low rent space for makers, craftspeople, artists and start-ups.

It could offer a more sustainable transport hub, affordable workspace and up to 1,500m² of affordable small-unit housing.

So, rebuild or retrofit? Low-carbon conversion or investment in new build to create capital for larger family housing?

Cambridge Architecture 27

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Technical

Change for change’s sake Together with colleagues from the Greater Cambridge Planning team, 3C Building Control responded to the next phase of government consultations aiming to positively affect climate change, which closed on 13 April. This time it was the Future Buildings Standard, generally looking at non-domestic buildings

Like the Future Homes Standard, the Future Buildings Standard will set challenging principles for new and existing buildings. And everyone is hopeful that changes to the Building Regulations will lead to positive climate change. The consultation this time was technical and complicated, looking at the relationship of fabric efficiency, solar gains, cooling requirements, daylighting, and the risks of overheating – which will be a very delicate balance. It predominantly references draft Approved Documents F and L. Solar shading will probably form an integral part of building design and must not come from impermanent things, such as trees. Where balconies are used as shading, they should not contribute to thermal bridges and we must understand the orientation of a building; they might not offer the same benefit to all elevations! The consultation seeks to use Primary Energy as the ‘principal performance metric’. This is defined as ‘energy from renewable and non-renewable sources which has not undergone any conversion or transformation process. It is a measure of the total energy used, including energy losses from extraction, processing, conversion and transportation’ – but I must confess to being confused by it as a measure and how useful it might be. London Energy Transformation Initiative (LETI) might have a better idea; setting energy use intensity targets in kWh/m².yr. This way, goals are set for how a building works in reality. In some respects, the consultation document is not ambitious enough. It uses those old ideas for existing buildings that they should ‘not be worse than they were before’, when there is often a clear opportunity to make improvements. This consultation is taking a serious look at what we need to do to halt climate change and respond to recent infection-control concerns. So, we should shout for joy, we should sing its praise! But only, as the draft Approved Document F suggests, if we ventilate at 15 litres per second per person with outdoor air for rooms that have ‘aerosol-generating activities’. It is likely that you will not be able to recirculate air from other spaces

WRITTEN BY: NICK KENDALL, COMMERCIAL MANAGER AT 3C SHARED SERVICES

“Solar shading will probably form an integral part of building design”

unless it goes through a series of filters, including UV, HEPA and germicidal. I think we need to focus on the passive advantages of fabric efficiency, good design and quality construction – and this only comes from us all working together. Future building design will be different, but there will definitely be a future – for cleverly considered, carefully constructed buildings.

Cambridge Architecture 29

Work in progress Soham Mill Purcell

Purcell will shortly complete the refurbishment and extension of a disused late 19th century mill building in Soham, to convert it into a theatre and multi-use space for a local community arts charity. The original mill has been thoroughly refurbished to provide the theatre’s main auditorium and social space.

Refurbishment of 17th century Grade II listed cottage Mart Barrass Architect

MBA(Ltd.) is developing proposals for the refurbishment, remodelling and extension of a Grade II listed 17th century cottage in South Cambridgeshire. The work includes reorganisation of the internal circulation, thermal improvement of the building fabric incorporating sheep’s wool insulation, re-rendering in lime mortar and re-roofing with reclaimed clay tiles. The heating system will be upgraded, replacing the existing oil-fired boiler with installation of an air source heat pump. A new angled, vaulted, metal and glass extension, designed to contrast with the historic building, will provide 21st century living accommodation and a new connection to the rear garden (currently obstructed by two 1980s lean-tos). A new detached garage will also incorporate solar panels to power an electric car.

Mill Road studio24 is working on designs to redevelop a prominent corner site at the edge of Mill Road Conservation Area, which is looking to heal the urban fabric using Victorian and 1950s architectural translations.

30 Cambridge Architecture

studio24 architects

Spotlight on projects by Chartered Practices North West ElevationExisting

Salvation Army new facilities Archangel Architects

Refurbishment work on The Worship Hall and Community Centre in Tenison Road, Cambridge, has begun. This work has been many years in the making and will give a much-needed update to facilities. Work is due to be completed this autumn.

North West ElevationExisting

GL 147.720

Winter Down House NP Architects Planning permission has just been granted for a new home in Aldeburgh. The house is configured with a C-shaped ground-floor plan, providing a private, south-facing garden, blocking views from neighbouring buildings. The projecting front portion of the building acts as a drive-through entrance porch. Views of the landscape/horizon can be seen to the south from the lookout on the top storey. The external materials are layered horizontally to relate to the wider landscape of the pitched existing garage roofs of nearby houses.

GL 147.720

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South West Elevation

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Cornwall cottage D

Bassett Architects UFH Manifold

GL 147.720

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UFH Manifold

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high level window

high level window pantry Tv chest 540h

wm Proposed deck 147 .720

drier

pantry

stove c'pd 1070h

freestanding unit 1820 h

Tv chest 540h

brooms ovens ff

wm ff

stove c'pd 1070h

drier

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smaller sofa 720h

ovens

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drier

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27.4 sqm GF extensions

brooms

ovens ff

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147.

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ovens

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smaller sofa 720h

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Bassett Architects are working on the renovation of 1970s cottage in Cornwall. The project will see the building upgraded to a high thermal standard and this, with the installation of an air source heat pump, will free it from its oil-fired boiler. A simple dormer extension accesses a terrace over a new glazed ground floor living room and will allow enjoyment of the sea views in all seasons. The project is at tender stage with hopes to move forward to construction within the coming months.

smaller sofa 720h

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Cambridge Architecture 31

.33

0 high level window

GL 147.720

Proposed FFL 147.870

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Articles inside

Change for change’s sake

Rebuild or retrofit

Social success

Designing out waste

In profile

Leading the (ex)change

Retrofit ethics

The retrofit village

News

Roadmap to retrofit