Residential Retrofit

Twenty Case Studies

Marion Baeli

• Publisher: RIBA Publishing
• Year: 2019
• ISBN:
  9781000705157
• Edition: 1
• Topic: Arquitectura
• Subtopic: Arquitectura general

The essence of sustainability in buildings is their capability to adapt to change over time. The UK has a large housing stock that has been developed and evolved over generations, and become the fabric and character of our cities, towns and neighbourhoods. The capability of buildings to adapt to changing lifestyles is the root of their sustainability. When buildings do not adapt they are disposed of, since it is only active use that confers value. It is only value that provides necessary investment for renewal.

This book presents a series of innovative and best practice case studies of residential low energy retrofit projects, and illustrates what has been achieved in practice in the UK.

Chapter 1
Introduction

The UK housing stock holds a strong identity and cultural significance for the British and for people across the world. Rows of Victorian terraces with coloured front doors are often seen as a quintessential part of the British aesthetic. It is a recognisable housing stock and one of the oldest in Europe with 55% of its dwellings dating from before 1960.¹

1 http://bpie.eu/ page 36 Figure 1B1 – Age profile of residential floor space

As they were built at a time when the use of fossil fuels, emissions of greenhouse gases and the expectation of changes to our climate were not a concern for people across the planet, the building fabric of these houses was not originally designed to retain heat energy particularly well and their occupants adapted to the vagaries of UK winter temperatures and an average indoor temperature around 12ºC mainly by adjusting their attire.²

2 www.decc.gov.uk/assets/decc/11/stats/climate-change/3224-great-britains-housing-energy-fact-file-2011.pdf page 100

Since then, standards of comfort and our outlook on activities surrounding our energy use, in particular in the built environment, have changed vastly. Rising levels of greenhouses gases, mainly CO₂, are increasingly becoming a concern for most of the world’s governments. Recent UK governments have recognised this concern and in 2008 introduced a legally binding Act of Parliament targeting a reduction of greenhouse gas emissions of at least 80% by 2050, with a reduction in emissions of at least 34% by 2020 (both targets are set against a 1990 baseline).

DECC (the UK Department of Energy and Climate Change), the key department in charge of implementing these targets, is undertaking extensive research into the field. In particular, they have identified that in 2009, 38% (678 TWh/yr) of the UK total CO₂ emissions came from ‘buildings in use’ and, more relevantly, that 28% (501 TWh/yr) are directly linked to ‘residential buildings in use’.³ However daunting this sounds, being part of the problem means that those UK residential buildings are also part of the solution.

3 www.decc.gov.uk/assets/decc/11/stats/climate-change/3224-great-britains-housing-energy-fact-file-2011.pdf page 5

But retrofit is not only about participating in the reduction of CO₂ emissions. It is also about avoiding the dilapidation of buildings that have become uninhabitable, helping to future-proof houses against the risks of fuel poverty and, last but not least, providing comfort for occupants.

So what are the Solutions?

With 27 million existing dwellings and only 120,000 new homes built every year, most of which are additional, the solution of relying purely on the new housing stock would fall a long way short of the Climate Change Act target. Over two-thirds of the 2050 housing stock has already been built; therefore the challenge is deciding what can be done with existing buildings. How can we ensure their continuing use, ensure continuing financial investment to avoid dilapidation, ensure that they are still representative of British cultural identity and at the same time deliver the levels of reduction in energy use required to address the impending environmental crisis?

Research needs to be carried out and solutions offered to all parties – homeowners, landlords, builders, tenants, housing associations – to help them achieve the required level of reduction in energy use. Equally important is the need to provide an adequate level of indoor comfort and quality of life for the 18% of all householders⁴ falling into fuel poverty,⁵ most of whom live in the least efficient housing stock.

4 www.poverty.org.uk/80/index.shtml#g2

5 www.poverty.org.uk/80/index.shtml#g2 Households are considered by the Government to be in ‘fuel poverty’ if they would have to spend more than 10% of their household income on fuel to keep their home in a ‘satisfactory’ condition. It is thus a measure which compares income with what the fuel costs ‘should be’ rather than what they actually are. Whether a household is in fuel poverty or not is determined by the interaction of a number of factors, but the three obvious ones are: the cost of energy; the energy efficiency of the property (and therefore, the energy required to heat and power the home); household income.

So what options do we currently know of that could transform old houses to both offer comfortable environments and do so in a way that is responsible and not detrimental to people’s future? Could demolition and rebuild be an option?

Several interesting reports have been written to help answer this question. They do not offer a clear-cut answer, of course, as many factors play an important role in this issue, such as the quality and efficiency of the replacement building, its embodied carbon level and the cost of energy in the future among others. However, the overall balance seems to lean towards a retrofit option rather than demolition and complete rebuild for the following reasons:

From a societal point of view, retrofit seems to be more acceptable than complete rebuild,⁶ especially when complete relocation would be necessary (see Pathfinder programmes⁷). Addressing the issue ‘in situ’ could also provide a boost for existing communities to implement greatly needed revitalisation schemes and help people out of fuel poverty by assisting them to confront increasing fuel prices and adverse effects on their health and standard of living. It could also potentially create long-term employment by encouraging the industry to develop the necessary skills and technologies to implement these retrofits.

6 A. Power, Does demolition or refurbishment of old and inefficient homes help to Increase our environmental, social and economic viability?, Elsevier Ltd. (2008).

7 www.audit-commission.gov.uk/housing/marketrenewalpathfinders/pages/default.aspx Grant Shapps [holding answer 10 July 2012]: I refer the right hon. Member to my answer of 25 June 2012, Official Report, columns 10-11W, which outlines the damaging obsession with demolition under the last Administration’s Pathfinder scheme, and the role of central Government in promoting demolition targets. The figures in the Audit Commission reports were provided by local authority pathfinders. I would also note the National Audit Office’s estimate that there were plans for a total of 57,100 properties to be demolished. This Government has cancelled the Pathfinders programme and is instead actively seeking to get empty homes back into productive use.

From an environmental point of view, retrofits have proven to have typically far lower impact. Retrofitting rather than rebuilding could make an initial saving of 35 tonnes of CO₂ per property by removing the need for the energy locked into new build materials and construction.⁸ They could also help address the increasing scarcity of materials and pressure on land availability across the country.

8 D. Thorpe, Sustainable Home Refurbishment (2010), 4.

So addressing the inefficiency of our building stock by providing instead highly efficient and responsible living places would seem to be a way to play a significant part in achieving CO₂ emissions reduction. However, as explained above, this is not purely a matter of limiting damage from the adverse effects of climate change; it is also a much wider opportunity for our society to become more sustainable as a whole.

How is Retrofit Defined?

For the purpose of this publication, it is important to clarify what is meant by ‘retrofit’. It will be defined here as a construction approach involving the action of introducing (retrofitting) new materials, products and equipment into an existing building with the aim of reducing the use of energy of the building. The term ‘retrofit’ is used in this publication to differentiate these projects from ‘renovations’ or ‘refurbishments’, which are often related to making good, repairing and/or aesthetically enhancing an existing building.

The phrase ‘deep retrofit’ is often used. The ‘deep’ character of a retrofit project further implies that the combination of elements introduced will have a very strong impact on the existing building’s level of CO₂ emissions, typically aiming for an 80% reduction in line with the Climate Change Act target figure.

It is worth mentioning that achieving a CO₂ emission reduction target of 80% implies a level of energy efficiency that vastly surpasses the current Building Regulation (and even BREEAM refurbishment) mandatory requirements for works on existing dwellings, and even surpasses current performance requirements for new build dwellings.

About this Book and the Retrofit for the Future Programme

In this publication, you will find 20 case studies that aim to illustrate how UK practitioners have approached this challenging target in the context of existing residential buildings. All but two of the case studies have been drawn from the Retrofit for the Future programme (described on the following page) and have similar typology (individual houses; there are no flats), tenure (social tenants), budget (including £150,000 funded by TSB) and targets (reducing CO₂ emissions by 80%). Each of the Retrofit for the Future project teams followed their own procedures for designing their retrofit strategy, but had the same way of defining a baseline project pre-retrofit against which the proposed measures could be compared and the same energy prices.

These individual houses have also been chosen to represent the UK housing stock in all construction variety – solid masonry, cavity walls, timber frame etc. – classified into two categories as either ‘pre-1919’ or ‘post-1919’ (corresponding to the time when UK construction techniques shifted from solid masonry to more efficient construction with cavity walls), to offer as wide a picture as possible of what retrofit can entail.

So these projects are certainly pioneering – among the first in the UK to aim for such levels of efficiency – but they were all also designed to lead to solutions that are replicable on a much larger scale. For example, they mostly use materials and products that are mainstream and readily available in the UK and can be mostly installed with standard skilled labour. Of course difficulties have arisen and the need for further developments is certain, but these cases are aiming to draw out useful lessons learned for the whole industry as we are considering large-scale implementation of these deep retrofits.

The Retrofit for the Future (RftF) programme was initiated by the Technology Strategy Board in 2009 with £17 m of funding through the Small Business Research Initiative (SBRI). The aim was to demonstrate innovative approaches to deep retrofitting of the UK’s social housing stock.⁹

9 www.retrofitforthefuture.org/leb/about-the-leb-database/

The RftF programme was split into two phases: Phase 1 saw 194 design and feasibility studies developed, while Phase 2 took 86 of these studies and provided each with up to £150,000 to implement the retrofit proposals in more than 100 properties. Eighteen of the 20 projects presented in this publication are drawn from the RftF programme and they represent a cross-section of different building types, ages, regional locations and technological solutions.

Applicants to the RftF competition were required to take a ‘whole house’ approach to achieving an 80% CO₂ emission reduction target. This meant considering a...

Table of contents

• Cover
• Title
• ACKNOWLEDGEMENTS
• CONTENTS
• DEFINITIONS
• FOREWORD
• PRACTICE PROFILE
• CHAPTER 1: INTRODUCTION
• CHAPTERS 2 AND 3: INTRODUCTION
• PROJECT LOCATIONS MAP
• CHAPTER 2: PRE-1919
• CHAPTER 3: POST-1919
• CHAPTER 4: COMPARATIvE COMMENTARy
• ABBREVIATIONS
• PICTURE CREDITS