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Research Report
on Obtaining Planning Permission for
Retrofitting Homes
to Reduce Carbon Emissions
Dr. Suzy Nelson
2
Acknowledgements
I would like to thank all those who shared their experience of domestic retrofit
projects with me and the members of the Architects Climate Action Network Existing
Buildings Working Group for their encouragement.
Dr. Suzy Nelson nelsons@westminster.ac.uk
3
Contents
0. Executive Summary .................................................................................... 4
1. Introduction .................................................................................................. 5
2. Research Method ........................................................................................ 6
3. Research Findings ...................................................................................... 7
3.1 The range of issues raised ........................................................................... 7
3.2 Different approaches to applying for planning permission .......................... 7
3.4 Inconsistency in the interpretation of policy................................................. 8
3.5 Pre-application advice .................................................................................. 8
3.6 Lack of joined up Local Authority policy ...................................................... 9
3.7 Conservation policy given priority ................................................................ 9
3.8 The form of extensions ............................................................................... 10
3.9 Application forms unsuitable for retrofit projects ....................................... 10
3.10 Applications based on archetypes ........................................................... 10
3.11 Planners’ lack of knowledge about retrofit............................................... 11
3.12 Design and access statements ................................................................ 11
3.12 Requests for detailed information ............................................................ 11
3.13 Delay in processing applications ............................................................. 11
3.14 The finish of external wall Insulation ........................................................ 12
3.15 Installation of external service pods ........................................................ 13
3.16 Roof heights and chimneys...................................................................... 13
3.17 Windows and Double Glazing .................................................................. 13
3.19 Solar Panels ............................................................................................. 14
3.20 Suggestions for streamlining planning to facilitate retrofit ...................... 15
4.0 Emerging Good Practice ............................................................................ 15
5.0 Conclusion and Recommendations ........................................................... 16
6.0 References ................................................................................................. 18
4
0. Executive Summary
Increasing domestic energy efficiency is vital to achieving the UK Government’s
commitment to reducing the emission of greenhouse gases. However, the current
rate of improvement is well below what is needed. Improving the energy efficiency of
our homes involves upgrading the building fabric and installing systems for controlling
internal temperature and moisture movement. Obtaining planning permission for these
improvements has been identified as one of the barriers to implementing retrofit
projects. However, there is a lack of evidence about the extent of the problem. This
research aims to contribute to filling this gap.
The research involves interviews with built environment professionals about their
experience of implementing domestic retrofit projects in England. It investigates the
extent to which obtaining planning permission was an obstacle to implementation in
both conservation areas and non-designated areas, and suggests possible
improvements to planning policy and procedures.
The research identifies a number of areas in which the planning system in England
currently hinders the implementation of domestic retrofit projects. These include lack
of clarity and inconsistency in the implementation of policy, conservation policy being
given greater weight than energy efficiency policy, planning officers’ lack of knowledge
about retrofit, application forms unsuited to retrofit projects, and delays resulting from
an under resourced planning system as well as problems relating to the retrofit of
specific building elements.
Recommendations for changes to the planning system and to local authority practice
include:
• revising regulations for permitted development in England
- to promote a fabric first approach to retrofit;
- to allow the installation of heat pumps with a noise output below a certain
decibel level;
• amending the National Planning Policy Framework for England
- to require local planning authorities to produce guidance on domestic
retrofit based on new national model retrofit guidance;
- to balance the weight given to energy efficiency improvements with that
given to protecting heritage in making decisions about planning
applications;
• permitting development which is in compliance with local retrofit guidance;
• training on retrofit for local authority planners;
• appointing a lead planner on retrofit in local authorities;
• amending local plans to require energy impact statements;
• ensuring effective local authority cross departmental working.
5
1. Introduction
The Committee on Climate Change (CCC, 2019) has advised the UK Government
that, in order to meet its commitment under the Climate Change Act 2008 to reduce
the emission of greenhouse gases, there needs to be a major improvement in the
energy efficiency of our housing stock. It reported that energy use in the existing 29
million homes in the UK is responsible for 14% of carbon emissions. To meet the target
for reduction in emissions near complete decarbonisation of the housing stock is
needed. This will involve both reducing energy demand through upgrading its fabric
and moving away from using fossil fuels for domestic heating.
It is estimated that 80% of the homes which will be in use in 2050 already exist (Alabid
et al, 2022). Most of these homes were built prior to any Building Regulations
requirements for insulation to limit heat loss. Domestic retrofit involves upgrading the
fabric of our homes and the systems for controlling their internal temperature and
moisture movement. As the priority is to reduce the demand for energy, a ‘fabric first’
approach focussing on reducing heat loss is widely advocated by construction
professionals (see for example CLC, 2021).
The Committee on Climate Change (CCC 2022a) has recently reported that the rate
of improvement in the energy efficiency of buildings is well below what is necessary.
It highlighted that the pace of improvement to the fabric of existing buildings needs to
be ramped up quickly (CCC, 2022b). Obtaining planning permission has been
identified as one barrier to implementing retrofit (see for example Ince & Marvin, 2019).
Improvements which will normally require planning permission include a change in
visual appearance resulting from installation of external insulation, raising the level of
roof and installation of air source heat pumps within one metre of a boundary
1
. As
permitted development rights only apply to single family dwellings, a wider range of
improvement to blocks of flats or houses which have been sub-divided require
planning permission (MHCLG, 2019). The Construction Leadership Council (CLC,
2019) advocates the streamlining of planning procedures to facilitate the
implementation of retrofit. It proposed the use of Local Development Orders for retrofit
and automatic planning permission for specific retrofitting works.
Listed buildings and those in conservation areas are subject to further restrictions on
improvements. The rights to undertake certain types of development which are
permitted elsewhere can be suspended in conservation areas by local planning
authorities issuing Article 4 directives (UK Government, 2015). Friedman and Cooke
(2012) conducted research on the extent to which UK planning was a barrier to energy
efficient heritage retrofit. Their research focussed on Inner London boroughs and
involved a survey of planning policies and documents, and interviews with
conservation officers. They found a lack of consistency in the application of planning
policy and concluded that in order to ensure project compliance in a timely fashion,
projects defaulted to the least disruptive baseline, resulting in less energy efficient
measures being undertaken. Based on their experience from the Retrofit for the Future
Programme, which involved government sponsored deep retrofits, Lewis & Baeli
1
https://www.planningportal.co.uk/permission/common-projects/heat-pumps/planning-permission-air-
source-heat-pump
6
(2012) found that the installation of replacement windows was the most consistently
adopted measure. They argued that high performance double or treble glazed
windows can closely resemble historic sash windows. However, they found that
heritage considerations often trumped human comfort and energy savings, and that
replacing windows frequently involved difficult and lengthy negotiations.
Availability of funding for retrofit is a crucial factor in determining the number and scale
of retrofit projects. Regrettably, the UK Government has failed to develop a coherent
policy to support retrofit on the scale needed. Whilst devolved governments in
Scotland and Wales have responsibility for housing, energy and planning, the UK
remains responsible for these matters in England. Currently English local authorities
and other providers of social housing can apply to the Social Housing Decarbonisation
Fund to improve the energy efficiency of properties (BEIS, 2022a). Local authorities
can also apply for funds from the Local Authority Delivery Scheme (LADs) and to
administer Home Upgrade Grants (HUGS). Both schemes are aimed at low-income
households living in homes with poor energy performance ratings. LADs is for
upgrading homes heated by gas and HUGs is for homes not on the gas grid (BEIS,
2021). All of these schemes have limited funding and tight deadlines for works to be
completed. The Government also requires energy companies to help their low-income
customers make energy saving improvements to homes with low energy ratings
(BEIS, 2022b). Grants are also available to cover part of the cost of replacing fossil
fuel heating systems with heat pumps
2
. The Green Deal and the Green Homes Grant,
which aimed to encourage a broader range of householders to retrofit their homes,
failed to realise their objectives and were short lived (Bergman and Foxman, 2020;
Blackman, 2021; Pullen, 2021), This pattern of public funding results in much of the
retrofit activity in England tending to focus on improvements to specific building
elements of homes in the social housing sector or homes of low-income homeowners
or private sector renters. Deep retrofits involving more ambitious levels of energy
efficiency for the most part are commissioned by homeowners who have the resources
to pay for such improvements (Fawcett & Killip, 2014).
Whilst commentators have identified the requirements of planning permission for
domestic retrofit projects as a barrier to implementing retrofit projects and advocated
streamlining planning procedures, there is a lack of evidence about the extent of the
problem. This research aims to contribute to filling this gap. It investigates the extent
to which built environment professionals found obtaining planning permission an
obstacle to implementing domestic retrofits both in conservation areas and in non-
designated areas in England, and explores what changes to planning procedures and
policy could facilitate the implementation of domestic retrofits. It includes experience
of projects ranging from small scale one-off retrofits for owner occupiers to large scale
retrofits of social housing.
2. Research Method
Building professionals involved in domestic retrofit projects were identified through the
Architects Climate Action Network, the Association for Environmentally Conscious
2
https://www.gov.uk/apply-boiler-upgrade-
scheme#:~:text=Through%20the%20Boiler%20Upgrade%20Scheme,to%20apply%20for%20the%20
grant.
7
Building, Passivhaus Trust and Retrofit Works. Possible further participants were
identified by those who participated in the research. The interviews followed a semi-
structure format. Interviewees were asked about the range of retrofit projects with
which they were involved, their experience of obtaining planning permission, any
issues concerning particular building elements and how they thought planning policy
and procedures could be improved. Most of the interviews were conducted and
recorded using Microsoft Teams, but two of the participants in the research opted to
respond to questions in writing. It was originally proposed to conduct twenty interviews,
but as the varied nature of experience became clear during the conduct of the
interviews, a total of 38 people were interviewed. Many public funded projects did not
involve architects or surveyors and were being implemented by specialist installers or
using existing framework contracts. Twenty interviewees were architects, who were
mostly working directly for clients, but sometimes were employed by contractors.
Other interviewees included housing managers, contractors, surveyors and retrofit
coordinators. Interviewees were responsible for projects in a wide range of locations
in England and some also had experience of working in Wales and Scotland.
3. Research Findings
3.1 The range of issues raised
The issues raised in the interviews included different approaches to applying for
planning permission, inconsistency in the interpretation of policy, pre-application
advice, lack of joined up policy, conservation policy being given priority, the form of
extensions, application forms unsuited to retrofit projects, applications based on
archetypes, planners’ lack of knowledge of retrofit, design and access statements,
requests for excessive detailed information and delay in processing applications.
Interviewees also reported difficulties in obtaining planning permission for external wall
insulation, external service pods, raising the height of roofs, new windows and double
glazing, heat pumps and solar panels.
3.2 Different approaches to applying for planning permission
The extent to which planning was an obstacle to implementing domestic retrofit
projects varied considerably. This was in part due to the different approaches taken to
applying for planning permission. All those interviewed generally tried to avoid
planning permission being refused. However, some were more cautious, whilst others
tried to push the boundaries of policy. One architect explained:
‘Typically we try and avoid refusals at all costs. the only reason we might accept a refusal is if
we felt so strongly about the principle of something that we wanted to take it to appeal’.
Another described his approach as a juggling act:
‘We really try to really understand what is going to be possible with the local policy but also
pushing at it a bit’.
Those working on social housing projects were constrained by funding conditions and
tight deadlines, and therefore selected the projects that would be easiest to deliver. A
housing association energy services manager responsible for a programme of
external insulation and heat pumps explained: ‘We're looking for the easy wins in this
phase’. However, there were concerns that there would be future challenges in
decarbonising social housing. One housing association manager was concerned
8
about social rented homes in listed properties; he feared that the difficulties in getting
planning permission for retrofit might result in selling off them off and that this would
result in no social housing being available in some neighbourhoods.
3.4 Inconsistency in the interpretation of policy
The uncertainty about policy and how permitted development would be interpreted by
different planning authorities was an issue for many of the interviewees. As one
architect explained: ‘There's no consistency across different authorities. it's still a
lottery’. Another commented: ‘ You're quite often at the mercy of personalities and then
the skill set of people.’ Interviewees found that in the absence of clear policy on retrofit,
the response from individual planners within the same authority could vary
considerably.
The lack of clarity about policy was exacerbated by the difficulties in having a
dialogue with planners. The sustainability lead for a large housing association
explained:
‘It’s very bureaucratic rather than a discursive process. And quite often you know It becomes
quite an adversarial process as opposed to a discursive process, and I think that's one of the
things that we’re very keen to see is being able to have an open, frank discussion with
planners at the earliest possibility.’
One architect commented:
‘Previously, back in the day, you used to be able to call up the planning department and have
a conversation. You're not allowed to do that anymore and they aren't allowed to engage in any
conversation about a project without having a fee. We don't have an issue with paying for the
advice, but in order to get that, you have to wait weeks and weeks for a meeting.’
Another interviewee explained that In the last few years it has become even more
difficult to have any discussion with planners:
‘We've seen a massive impact post COVID or from the start of COVID really. Everyone
started working at home and they haven't really come back to the office. It used to be that you
could pick up the phone and speak to a planning officer, and you just can't now’.
3.5 Pre-application advice
There were mixed views about the value of pre-application advice. As one architect
explained:
‘We'll test the water with planning as priority number one really. So as soon as we are anywhere
close to satisfying the client’s brief we're putting in a pre-application on 95% of projects, but a
pre-app is a nightmare for us because it takes a long time. Most of the time I would say the pre-
app advice is clear enough that it gives us something to respond to., but that's been less of a
guarantee since the pandemic. I suppose because teams are stretched thinner and people are
working remotely and then in sort of different hybrid ways, I’d say nowadays it's quite rare that
you get feedback from a pre-app officer and it's the same person looking at the main
application.’
Another commented:
‘Although we were advocates of pre-apps. It's just everything is taking a long, long, long, long,
long time these days. The person that you dealt with in pre-application isn't the person you're
dealing with in the main application. And refusals happen all the time. It forms part of why we're
maybe questioning a bit more whether we continue to go down a pre-application route. It was
different when we were able to meet with an officer at the site and have a discussion.’
Because of doubts about the value of pre-application advice interviewees were
increasingly employing planning consultants to advise on applications.
9
3.6 Lack of joined up Local Authority policy
Many local authorities had declared a climate emergency, but this often had not
changed how planners operated. The construction advisor for a whole house retrofit
system who was working on social housing projects, explained:
‘A lot of local authorities are committing to net zero and all that, but that message isn't
necessarily being passed down to the planning department. So, you're beginning to get a
complete disjunct really between the philosophical objectives of the members and the
directors, and then the officers who haven't really been given any guidance’.
Another interviewee commented:
‘Our Council has signed up to the climate emergency, so they all have that kind of in the
background, but it's not so much in the detail’.
A planning consultant thought that government performance indicators for local
authorities focussing on the number of new homes meant that upgrading existing
homes was not a priority for local planners. She explained applications for retrofit
projects:
‘… are not considered a major application, so you get very, very junior people on them. They're
not high priority because they're not delivering new housing, so they're not contributing to
meeting targets’.
Problems also arose between local authority departments. One local authority housing
development manager reported that planners refused permission for external wall
insulation on council owned street properties, despite it having been previously
granted for properties in the same street. As a result, she was in dialogue with the
planning department about having a dedicated planning officer to deal with retrofit
projects.
3.7 Conservation policy given priority
Getting planning permission for retrofit projects in conservation areas and for listed
buildings presented particular problems. As one architect put it: ‘Conservation trumps
thermal performance pretty much always’. Interviewees wanted to make energy
efficiency improvements, which respected the fabric of historic buildings, particularly
street elevations. One elaborated:
‘The front is always going to be a concern, even if it's not a conservation area. So we’ve decided
that, if there are very similar houses on the street all the way down, we didn't want to spoil the
street scene so we've ended up internally insulating on the front’.
Another explained that when working on projects in conservation areas:
‘At day one, there's a realisation that some things are definitely off the menu, so we agree with
the conservation officers to some degree. But we found that there's a middle area where we
think things are wholly appropriate in many instances, and they tend to think they're completely
outrageous’.
Some interviewees were able to have a positive dialogue with conservation officers,
but experience was mixed. As one architect explained:
‘Some of them are excellent and you have a really positive kind of dialogue with them. You
cannot agree on everything, but you can work out where they are coming from and you can
come to some sort of compromise. But some of them are completely unreasonable’.
Others were unable to have any direct dialogue with conservation officers, as another
architect reported:
‘We deal with the conservation officer via the conduit of the case officer, so we never get to
speak to the conservation officer in many cases’.
10
One conservation architect was experiencing a change of approach in the area
where he was working. He elaborated:
‘There are small, but relevant, changes in the policies and in the guidance. The title is now
conservation and sustainability officer, so they have the responsibility to also look at
sustainability within their remit. So it's a game changer and I think it's a welcome game
changer’.
3.8 The form of extensions
Retrofit projects for homeowners are generally part of a bigger remodelling projects,
and the form of the extended property affects its thermal efficiency, as heat loss is
proportional to the external surface area. However, this was not an issue which was
understood by most planners. Typically, the external surface area of existing back
extensions is high relative to the floor area. As part of a deep retrofit project, an
architect proposed a full width two storey extension, which made the external envelope
of the building more compact and thus thermally more efficient. The extension did not
have a negative impact on neighbouring properties, but it was resisted by the planners
as it did not comply with planning guidance
3
. As the architect explained: ‘As soon as
you depart from prescribed approaches, you're in trouble.’
3.9 Application forms unsuitable for retrofit projects
Current application forms are not well suited to retrofit projects. In one instance the
retrofit of a block of flats involved the construction of a new plant room and bin store
at ground level and the planners initially treated it as a new building and required a
flood impact assessment. In this instance the architect was able to negotiate and in
the end the planners conceded on this issue, but such negotiations can cause delay
and extra expense. In another case, 44 houses belonging to a local authority, which
were pepper potted around an estate, were being renovated, which caused the
architect problems in completing an online application form and getting it validated,
because the system would not accept that number of addresses. However, as the
homes being renovated only represented 10% of the estate, it was not appropriate to
include all of the estate in the application. The architect for these projects commented:
‘Whilst this might seem a minor administrative problem, in practice it proved quite a
challenge.’
3.10 Applications based on archetypes
Some interviewees had been able to negotiate submitting applications based on
archetypes. As one, who was working on a project involving retrofitting over 300 social
rented homes on an estate explained:
‘Only through meeting, we discovered that we could submit the application based on the
archetypes rather than based on every single property, and that's hugely reduced our
workload’.
This meant that they could submit plans, sections and elevations for each archetype
instead of having to do drawings for 300 plus properties.
3
In a conservation area ‘an extension from a rear wall is not permitted development if it
results in an enlarged area of the house that has more than one storey’ MHCLG, 2019,
p. 30.
11
The acceptance of applications based on archetypes would also be helpful for
retrofitting street properties. An advisor to an organisation, offering a system approach
to retrofit, reported that despite standardised designs for retrofitting ten houses in the
same street, the planners had required full applications with surveys, acoustic reports
and full drawings for all ten properties. This involved considerable expense as well as
delay and the permissions then came back at different times.
3.11 Planners’ lack of knowledge about retrofit
Local planners often had little knowledge about what was involved in retrofit. An
architect working on a project for homeowners found:
‘The Council resisted every single kind of option and weren't really prepared to engage with
retrofit. I didn't know quite how to manage that massive knowledge gap that was being
presented to me.’
Another architect commented:
‘I've talked to planning departments and understood just how little opportunity they were getting
for education, training on all this kind of stuff, which is super important’.
3.12 Design and access statements
As planning officers’ level of knowledge about retrofit was often limited, architects,
seeking approval for ambitious retrofits, had put a lot of effort into design and access
statements. As one architect explained:
’We get them through now, because we see the problem coming and we write quite lengthy
and well justified design and access statements.’
Another commented commented:
‘One problem is the amount effort one has to do on the research, report writing and convincing’.
3.12 Requests for detailed information
A number of interviewees highlighted the problem of planners asking for detailed
information at an early stage, which resulted in them having to undertake work at risk.
As one architect commented:
‘They are constantly asking for more and more information, like having to mock things up and
do 3D rendered views, before and after, even though they look the same. They wanted one to
fives
4
as well to show how it was going to work. Detail that you wouldn't expect to necessarily
be doing at RIBA Stage 3
5
.’
3.13 Delay in processing applications
The length of time it takes to get planning permission was a major problem. As one
architect commented:
‘It’s just the amount of time that things take. I'm not sure we've had a planning application go
through recently when there hasn't been a request for an extension
6
.’
4
Construction details at a scale of 1:5.
5
Royal Institute of British Architects Work Stage 3 Spatial Coordination is usually completed before
submitting planning, but Technical Design is carried at out in Work Stage 4.
6
The UK Government sets statutory limits to the time Local Planning Authorities are allowed for
responding to applications, However, LPAs regularly request extensions to these time periods, which
applicants usually accept to avoid the risk of refusal.
12
There were a number of consequences of these delays. Because of the tight deadlines
for funding for social housing, architects avoided improvements which might be
controversial, and they proceeded with detailed design work prior to getting planning
permission, which meant that they risked work being aborted and not getting paid. At
a time of a high inflation in construction costs, delays also had an adverse impact on
project budgets, which sometimes resulted in projects not going ahead.
Although there was widespread frustration about delays, interviewees were aware that
planning departments were under resourced. As one architect commented:
‘People are overworked and don't have enough time to deal with things. We're not critical of
planning officers, because they are grossly overworked.’
In 2019 the Royal Town Planning Institute indicated that the problem of under
resourcing of local authority planning services was worsening; it reported that in
England between 2009 and 2018 the expenditure of local authorities on planning
decreased by 42%.
3.14 The finish of external wall Insulation
Many interviewees had submitted planning applications for installing external wall
insulation. Whilst the installation of external wall installation is classified as permitted
development in England, this is subject to the condition that the materials used ‘ shall
be of a similar appearance to those used in the construction of the exterior of the existing
dwellinghouse’ (MHCLG, 2019. p.31). In practice, unless the existing finish is render,
the installation of external wall insulation usually involves a change in the finish of the
wall. Interviewees found that planners’ opinions varied about what constituted a similar
visual appearance; sometimes it was render of a similar colour to brickwork,
sometimes brick effect render
7
and sometimes brick slips.
There was a general consensus amongst interviewees that retrofits should be
sensitive to the existing street scene. However, in some streets the front elevations
have a variety of finishes. One architect was retrofitting a small brick end of terrace
Victorian house in a conservation area. As insulating internally would have made the
rooms too small, she submitted an application for external insulation with a rendered
finish, including on the front and side elevations. The application was successful due
to a carefully argued, detailed design and access statement. This showed how the
frontages of buildings in the street had a variety of brick and render finishes, and
explained how replacement windows were to be positioned to preserve the traditional
relationship with the external wall finish and how the roof was to be extended to cover
the insulation at eaves level. Many interviewees agreed that such attention to the
detailing of external insulation was more important than maintaining a similar finish.
A number of interviewees had experience of planners objecting to the installation of
external wall insulation at the rear of properties. As one architect who had been
consulted by a group of homeowners in a conservation areas explained:
‘It's very clear that they do not allow external insulation from the front. Fair enough. But the
backs of these houses, it's a higgledy, piggledy mess. And so saying ‘you can't put on external
insulation’ just seems extremely random, because for most of these people, internal insulation
is going to be a monstrous headache.’
7
Brick effect render involves applying a first coat of render matching the mortar colour and a second
coat the colour of the original brick, scored in the pattern of brickwork joints to reveal the render in the
mortar colour.
13
Problems also arose as a result of planners’ lack of flexibility about finish. One
architect found that planners viewed going from a red brick to a reddish render as
permitted development. However, her clients wanted a paler colour render at the rear
of properties with back extensions in order to reflect more light and this required having
to go through planning adding cost, uncertainty and delay. Another interviewee had to
resubmit to planning, because of a supply problem with the particular brick slips that
the planners had wanted.
A surveyor with extensive experience of working on retrofits in different parts of the
country was frustrated by the lack of consistency. He found that some planning
authorities would not consider external wall insulation with a rendered finish on very
average brick houses, whereas others permitted it on almost identical houses.
3.15 Installation of external service pods
A number of problems were reported regarding the installation of service pods on
retrofits of social housing. These units are designed to house all of the building
services including the air source heat pump, the solar panel inverter, the water tank
and the mechanical ventilation with heat recovery. They are manufactured off site and
thus their installation causes minimum disruption for tenants. On one project the
planners’ refusal to accept the integral grey finish of the pod and requirement for a
brick finish had caused six months delay. On another project retrofitting a terrace of
houses, it had originally been intended to house the service pods within new porches.
This did not need planning permission, as there are permitted development rights for
porches of up to three square metres (MHCLG, 2019). However, due to supply
problems the specification was changed to door height units which had to be installed
externally. It was proposed to install them adjacent to each front door below a canopy.
However, because the area below the canopy was not enclosed by a door, the
planners did not consider this to be permitted development and required a full planning
application to be submitted.
3.16 Roof heights and chimneys
Raising ridge lines to accommodate insulation was sometimes resisted by planners.
One architect commented:
‘There is an obsession to keep heights matching neighbours. But the problem is sometimes
these heights are too low to insulate properly internally.’
A surveyor recounted mixed experience:
‘Adding a layer of insulation 50mm thick over the rafters of a pitched roof, then counter-battens,
allows us to fully fill the rafter voids and more, creating really good U values. We have
successfully done this many times, but some boroughs just refuse to accept the concept.’
He had also found great resistance by planners to the removal of redundant chimneys,
which were major thermal bridges and often required costly maintenance.
3.17 Windows and Double Glazing
Planning issues frequently arose with replacing windows and installing double glazing
in listed buildings and in conservation areas. As one interviewee explained:
‘Getting any conservation area officer to allow you to install a new double glazed unit or even
double glazing into an existing frame is difficult’.
14
Highly thermally efficient replacement sash hung windows with fixed top sashes and
inward opening tilt turn bottom look very little different to traditional sashes. However,
another interviewee explained that he had found planners reluctant to accept them
‘even where the backs of houses were a riot of different things already’. In other
instances, conservation officers had refused to accept replacing the glazing in existing
sashes with ultra slim evacuated cavity double glazing. However, there were some
indications that conservation officers in some areas were becoming more open to
these innovations.
3.18 Heat pumps
Although the installation of air source heat pumps is classified as permitted
development subject to certain conditions (UK Government, 2015), in practice,
planning permission was frequently required, because the installation was within one
metre of the boundary, in a conservation area or the grounds of a listed building, or
did not comply with the Microgeneration Certification Scheme (MCS, 2019). This
frequently involved significant delays and additional expenses, as acoustic tests were
required to prove that the noise made by the heat pumps did not exceed the level of
background noise, which involved employing acoustic engineers. However, several
interviewees made the point that such tests were unnecessary in the context of recent
improvements in the technology. As one interviewee commented:
‘I think that in the past heat pumps had a higher noise level, but now they don’t. The new ones
are around 35 decibels. That is the noisiness of a fridge’.
On social housing projects, particular problems arose when more than one heat pump
or larger communal heat pumps were needed. This sometimes resulted in planners
requiring screens to dampen the noise output or requiring the pumps to be located
some distance away from the property making the system less efficient.
The renewable energy manager of a large housing association, which had been
installing air source heat pumps for 20 years, had a problem with planning permission
being required for replacement ones, because the replacement installation did not
comply with the current Microgeneration Certification Scheme guidance. He explained
that
‘We have to go for full planning and then by the time you eventually get it through planning, it
can take three to six months. That whole time, I've got a customer out of heating and hot water’.
3.19 Solar Panels
The installation of solar panels (solar photovoltaics and solar thermal equipment) is
permitted development subject to certain conditions (UK Government, 2015). The
conditions include siting them to minimise the impact on the external appearance of
the building. These permitted development rights do not apply to listed buildings and
street frontages in conservation areas. Local authority Article 4 directions frequently
further restrict development rights in conservation areas. Although planning
permission for solar panels on street facing roof slopes continues to be resisted,
several interviewees thought that planners’ attitudes were changing. One architect
whose projects were mainly in conservation areas recounted his experience:
15
‘I think councils are much more receptive. We're not even really having to go down the fake
tile route
8
. Although they definitely have their place and they are becoming possible on listed
buildings, where previously nothing was possible’.
3.20 Suggestions for streamlining planning to facilitate retrofit
There was a strong consensus amongst interviewees that there was a need for clearer
and more consistent policy on retrofit. As one interviewee explained:
‘We deal with so many different councils, so for us really there needs to be some sort of
nationwide policy on retrofit.’
It was argued that in order to scale up the delivery of domestic retrofit projects, there
needed to be an extension of permitted development rights, as one architect
suggested:
‘It would be possible to establish a series of design rules, specifically around retrofit, so that
then if you comply with them, it's deemed to be permitted’.
Interviewees also recognised that there was a need for local policy on retrofit. As one
interviewee explained:
‘The nuances and specificities of different sort of vernaculars can be developed at more of a
local level.’
As planning application forms are designed for new build, it was proposed that a new
application form, specifically for retrofits, should be introduced and that this should
allow for an application to be based on archetypes where appropriate. As current
national planning policy gives great weight to preserving historic buildings, those
involved in retrofitting historic buildings advocated energy efficiency being given
greater weight to allow more flexibility in upgrading them.
Many interviewees highlighted the need for planners to receive training on retrofit. As
well as focussing on design issues relating to energy efficiency, it was thought that
this should also cover the design process and cost constraints. Some suggested that
it should be the role of planners to actively promote energy efficiency.
Other recommendations were the appointment of a dedicated officer to deal with
planning for retrofits or of a retrofit champion who could work to ensure a joined-up
approach across council departments.
4.0 Emerging Good Practice
A number of local authorities are introducing new policies including some of those
suggested by interviewees. Some local authorities are now actively promoting
domestic retrofits. For example, Stockport Core Planning Strategy requires planning
applications for changes to existing dwellings, where possible and practical, to include
improvements to energy efficiency; applicants are required to submit an energy
efficiency statement and to complete an energy efficiency checklist
9
. Other local
authorities have produced guidance on how to retrofit. Brighton and Hove City Council
(2016) produced a planning advice note on energy efficiency for historic houses in
conservation areas, which indicates that external insulation and standard double
glazed windows may be acceptable on elevations not visible from the street. A number
8
Solar roof tiles incorporating thin film photovoltaic cells are now commercially available but are more
expensive than conventional roofs and solar panels.
9
https://www.stockport.gov.uk/energy-efficiency-statements
16
of local authorities have produced Special Planning Documents which provide advice
on retrofitting existing buildings (see for example, Bath and North East Somerset,
2022). These documents generally clarify how policy will be implemented, but do not
extend permitted development rights.
Westminster City Council has set up a retrofit task force to investigate solutions to the
challenge of retrofitting existing buildings. Its initial focus is historic buildings due to
the number of conservation areas and listed buildings in the borough. A number of
industry experts as well as officers from different council departments are members of
the task force. It is developing an action plan following workshops involving local
property owners and residents. It is producing guidance for householders on how to
retrofit. The first of the series provides detailed advice on making windows energy
efficient and explains what changes require planning permission (Westminster
Council, 2022).
Local Development Orders and Local Listed Buildings Consent Orders can be used to
remove the need for planning permission by specifying when development is deemed
to be appropriate (Historic England, 2015; Planning Advisory Service, 2019). They can
make the process simpler, less expensive and quicker for applicants, and reduce the
workload of planners. These orders have the potential to facilitate the implementation
of retrofit projects, but to date have largely been used for other purposes. In 2015
Wirral Council passed a Listed Buildings Consent Order for Port Sunlight, which has
a high concentration of Grade II listed buildings. Replacement rear doors, rear
windows and yard gates, which comply with the order do not need listed building
consent; a simple notice form is submitted to the Council, which confirms compliance
(Port Sunlight Village Trust and Wirral Council, undated). In 2017 Dudley Metropolitan
Borough Council introduced a Local Development Order, which allowed certain
householder extensions to be built without planning permission. As in Port Sunlight, a
simple application form needs to be submitted to confirm compliance. In 2022 the
Royal Borough of Kensington and Chelsea was the first in the country to introduce a
Local Listed Buildings Consent Order for the installation of solar panels on Grade II
listed buildings
10
and it is now consulting on another order for windows.
The Architects Climate Action Network’s Climate Emergency Conservation Areas
Toolkit (2023) provides guidance on how historic buildings can be made more energy
efficient whilst respecting the fabric of historic buildings. It provides detailed
information on how to insulate walls and roofs, and how to improve the energy
performance of windows. while also maintaining or improving the heritage value of the
conservation area.
5.0 Conclusion and Recommendations
This research has identified several areas in which the planning system in England
currently hinders the implementation of domestic retrofit projects. These include a lack
of clarity or inconsistency in the implementation of policy, conservation policy being
given greater weight than energy efficiency policy, planning officers’ lack of knowledge
about retrofit, application forms being unsuited to retrofit projects, delays resulting from
10
https://www.rbkc.gov.uk/newsroom/solar-power-more-homes-kensington-and-chelsea
17
an under resourced planning system as well as problems relating to the retrofit of
specific building elements.
In order to achieve the target of net zero the planning system needs to change from
obstructing the implementation of retrofit projects to actively promoting domestic
energy efficiency. This will involve changes in both national and local policies and
practice, speeding up the decision making process and ensuring that planning
departments are better resourced.
Based on this research the following recommendations for changes to the planning
system and to local authority practice are made.
a) The regulations on permitted development in England should be revised with a
view to promoting a fabric first approach to retrofit and facilitating the installation
of heat pumps and solar panels. Improvements to the energy efficiency of
homes which are not visible from the public realm should be considered
permitted development unless this would negatively impact on features of
historic interest.
b) The guidance on noise level requirements for air source heat pumps is a
particular topic which needs to be revisited; in the context of improvements in
the technology their installation should be permitted provided the noise output
is below a maximum decibel level.
c) The NPPF should require local English planning authorities to provide guidance
on implementing domestic retrofit projects. The Government should produce
national model guidance on retrofit. In a similar way to the National Model
Design Code (MHLG, 2021), this would set out principles for achieving high
quality design, which could then be adapted by local planning authorities to
provide guidance reflecting local character.
d) The NPPF should be amended to provide clearer and more positive guidance
on how to consider the impact of proposed energy efficiency improvements on
the conservation of a designated heritage asset, so that, when making
decisions on applications, significant (ie equal) weight should be given to both
improving energy efficiency and the protection of heritage assets.
e) Local retrofit guidance should clearly set out what retrofit measures will be
permitted. This should include details of where external insulation can be
installed, an acceptable range of finishes to external insulation, acceptable
changes in roof line to accommodate insulation, where chimneys can be
removed and what replacement windows and glazing are acceptable. Such
guidance could take the form of Supplementary Planning Documents, Local
Development Orders and Local Listed Building Consent Orders. All
development complying with the guidance should be permitted. Householders
should have the option of applying for certificates of permitted development if
they wish to have confirmation of compliance. Extending permitted
development rights in this way would offer greater certainty to householders
planning to retrofit their homes, and also has the potential to reduce the
workload of local authority planners.
18
f) Local planning authorities need to ensure that they have planning officers who
have a good understanding of the technical issues involved in retrofit. As well
as providing training for all planners on retrofit, this might involve appointing a
retrofit lead planner who could advise colleagues. In addition to providing local
guidance on retrofit, local planning authorities need to review how they can
actively promote retrofit. This might include amending the local plan to include
energy impact statements in planning applications and providing energy
checklists.
g) Local authorities need to review how they can develop joined up policy on
retrofit. One way to do this would be set up a cross departmental task force to
ensure effective liaison between their planning, building control and housing
departments to engage with industry and community representatives. It would
also be helpful to have retrofit champions within local authorities.
6.0 References
Alabid, J., Bennadji, A. and Seddiki, M. (2022) A review on the energy retrofit
policies and improvements of the UK existing buildings, challenges and benefits.
Renewable and Sustainable Energy Reviews, 159. 1-12.
Architects Climate Action Network (2023) Climate Emergency Conservation Area
Toolkit. Available from: https://www.architectscan.org/conservation-area-toolkit-
retrofit-homes
Bath and North East Somerset (2022) Energy Efficiency, Retrofitting and Sustainable
Construction Supplementary Planning Document. Available from:
https://beta.bathnes.gov.uk/policy-and-documents-library/energy-efficiency-
retrofitting-and-sustainable-construction
BEIS (2021) Sustainable Warmth Competition: Guidance for Local Authorities.
London: Department of Business, Energy and Industrial Strategy. Available from:
https://www.gov.uk/government/publications/apply-for-the-sustainable-warmth-
competition
BEIS (2022a) Social Housing Decarbonisation Fund Wave 2.1 Competition Guidance
Notes. London: Department of Business, Energy and Industrial Strategy. Available
from: https://www.gov.uk/government/publications/social-housing-decarbonisation-
fund-wave-
2#:~:text=The%20SHDF%20Wave%202.1%20competition,of%20the%20project%20
requires%20this
BEIS (2022b) Energy Company Obligation 2022-2026. London: Department of
Business, Energy and Industrial Strategy. Available from:
https://www.gov.uk/government/consultations/design-of-the-energy-company-
obligation-eco4-2022-2026
19
Bergman, N. and Foxon, T.J. (2020) Reframing policy for the energy efficiency
challenge: Insights from housing retrofits in the United Kingdom, Energy Research &
Social Science, 63, 1-12.
Brighton and Hove City Council (2016) Planning Advice Note. 09, Householder
guidance on energy efficiency for historic houses in conservation areas. Available
from: https://www.brighton-hove.gov.uk/planning/planning-policy/planning-advice-
notes-pans-and-technical-guidance
CCC (2019) UK Housing: Fit for the future. Available from:
https://www.theccc.org.uk/publications/
CCC (2022a) Progress in Reducing Emissions, 2022 Report to Parliament.
Available from: https://www.theccc.org.uk/publications/
CCC (2022b) Independent Assessment: The UK’s Heat and Buildings Strategy.
Available from: https://www.theccc.org.uk/publications/
CLC (2021) Greening our existing homes, National Retrofit Strategy, A Consultative
Document. Available from:
https://www.constructionleadershipcouncil.co.uk/news/national-retrofit-strategy-v2-
launches/
DLUHC (2021) National Planning Policy Framework. London: Department for
Levelling Up, Housing & Communities.
Dudley Metropolitan Borough Council (2017) Householder Extensions Local
Development Order. Available from:
https://www.dudley.gov.uk/residents/planning/planning-services/apply-for-planning-
permission/local-development-order/
Fawcett, T. & Killip, G. (2014) Anatomy of low carbon retrofits: evidence from owner-
occupied Superhomes, Building Research & Information, 42:4, 434-445.
Friedman, K.S. and Cooke, A,, (2012) Is UK Planning a barrier to energy efficient
heritage retrofit: a comparative analysis of a selection of London Boroughs.
Available from:
https://www.researchgate.net/publication/267225027_Is_UK_Planning_a_barrier_to_energy_efficient
_heritage_retrofit_a_comparative_analysis_of_a_selection_of_London_Boroughs/citations
Historic England (2015) Drawing up a Locally Listed Buildings Consent Order,
Historic England Advice Note 6. Available from:
https://historicengland.org.uk/images-books/publications/drawing-up-local-listed-
building-consent-order-advice-note-6/
Ince, R. & Marvin. S. (2019) Constructing domestic retrofit as a new urban
infrastructure: experimentation, equitability and contested priorities, Local
Environment, 24 (9) 825-842.
Lewis, S. and Baeli, M. (2013) Planners' calls for 'authentic' windows are inconsistent
with today's needs, Architects' Journal, 31 January, Vol. 237 Issue 4, p58.
20
MCS (2019) Planning Standards for Permitted Development Installations of Wind
Turbines and Air Source Heat Pumps on Domestic Premises. Daresbury, Cheshire.:
Microgeneration Certification Scheme. Available from:
https://mcscertified.com/standards-tools-library/
MHCLG (2019) Permitted development rights for householders, Technical Guidance.
London: Ministry of Housing, Communities and Local Government. Available from:
https://www.gov.uk/government/publications/permitted-development-rights-for-
householders-technical-guidance
MHCLG (2021) National Model Design Code: Part 2 Design Notes. London: Ministry
of Housing, Communities and Local Government. Available from:
https://www.gov.uk/government/publications/national-model-design-code
Planning Advisory Service (2019) Local Development Orders, Guidance for councils
on preparing local development orders. Available from:
https://www.local.gov.uk/pas/topics
Port Sunlight Village Trust and Wirral Council(undated) Port Sunlight Local Listed
Building Consent Order (LLBCO), A guide to understanding and using the LLBCO.
https://www.wirral.gov.uk/planning-and-building/planning-permission/port-sunlight-
local-listed-building-consent-
order#:~:text=Wirral%20Council%20and%20Port%20Sunlight,to%20regain%20lost
%20heritage%20features
Royal Town Planning Institute (2019) Resourcing Public Planning, RTPI Research
Paper. London: RTPI. Available from:
https://www.rtpi.org.uk/policy/2019/november/resourcing-public-planning/
UK Government (2015) The Town and Country Planning (General Permitted
Development) (England) Order 2015. Available from:
https://www.legislation.gov.uk/uksi/2015/596/contents/made
Westminster City Council (2022) How to make your windows more energy efficient,
Retrofit How-to-Guide One. Available from:
https://www.westminster.gov.uk/planning-building-and-environmental-
regulations/planning-and-climate-emergency/planning-householder-retrofit-how-
guides/make-your-windows-more-energy-efficient
Wirral Council (2015) Port Sunlight Village Local Listed Building Consent Order.
Available from: https://www.wirral.gov.uk/planning-and-building/planning-
permission/port-sunlight-local-listed-building-consent-
order#:~:text=Wirral%20Council%20and%20Port%20Sunlight,to%20regain%20lost
%20heritage%20features