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Hillingdon Planning Committee – 4th June 2026
PART 1 – Members, Public & Press
Report of the Head of Development Management and Building Control
Committee Report
Case Officer: Christopher Lamb 79535/APP/2026/11
Date Application
Valid:
19.01.26 Statutory / Agreed
Determination
Deadline:
08.06.26
Application
Type:
Householder Ward: Ickenham &
South Harefield
Applicant: Mr Norron Nyack
Site Address: 74 St George's Drive
Ickenham
Hillingdon
UB10 8HR
Proposal: Erection of single storey rear extension,
alteration to the roof of the existing single storey
garage, conversion of the main roof to habitable
accommodation comprising of 2 x side dormers
and hip
-to-gable extension to the rear, demolition
of existing chimney, and expansion of raised
patio area to the rear of the property (Part
Retrospective)
Summary of
Recommendation:
GRANT planning permission subject to
conditions
Reason Reported
to Committee:
Required under Part 3 of the Planning Scheme of
Delegation (Petition received)
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Summary of Recommendation:
GRANT planning permission subject to the conditions set out in
Appendix 1.
1 Executive Summary
1.1 This application seeks part-retrospective planning permission for the construction
of householder additions to No. 74 St. George’s Drive, Ickenham, namely a single
storey rear extension and conversion of the roof to habitable accommodation,
including dormers to both sides and a hip-to-gable extension to the rear. As part
of the proposal, the existing garage roof wo uld also be altered, in addition to the
expansion of the raised patio area to the rear and removal of a chimney.
1.2 Materially similar extensions to the prop erty have been previously granted under
the provisions of Permitted Development, i.e., demonstrated to show that they
would not require planning permission. This has included a single storey rear
extension, of similar depth and siting to that proposed, granted under prior
approval application (ref: 79535/APP/2025/1625), and the conversion of the roof
to habitable accommodation, including dormers to both sides and a hip -to-gable
extension to the rear , granted under a lawful development certificate (ref:
79535/APP/2025/1632).
1.3 The proposed scheme expands on these previous applications, making additional
alterations which would bring the development over and above the permitted
development threshold and hence have consequently required planning
permission to be sought. Following amendm ents made to the application, these
alterations include:
- Enlargement of the size of the west- facing dormer, so that it reflects the box
design of the east-facing dormer.
- To the rear, the dormers are no longer set in from the gable edge of the
roof, and include an additional window.
- Increased height of the rear extension by approximately 0.25m.
1.4 The proposed raised patio and garage roof alterations are new to this application
and have not previously been sought.
1.5 During the course of the assessment, further amendments were received from the
original submission which omitted a hip-to-gable extension to the front roof slope,
reduced the sizes of the side dormers (from the original planning submission) and
reduced the patio height in line with permitted development requirements. These
amendments ensure that the development to the front would appear similar to
what was previously approved and also not appear out of character. The reduction
of the
patio height would also ensure the amenity of neighbours is protected and
conditions have been added in regard screening measures to be submitted.
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1.6 Three signed petitions have been received from the public with a total of 181 valid
signatures, and as such this application has been called to Committee for
determination
. Concerns raised include, inter alia, the impact of the proposal on
neighbour amenity, impact on the character and appearance of the area, including
overdevelopment of the plot, and impact on flood risk. The comments also raised
concerns regarding the retrospective nat ure of the application and construction
management of the site.
These matters have been considered within the
assessment section of the report below.
1.7 With consideration given to what has already been granted, i.e. can already be
built without requiring planning permission under the provisions of Permitted
Development, the proposal is considered to comply with the objectives of the
relevant planning policies and would not give rise to any materially greater harm
to the character and appearance of the area or neighbour amenity, beyond what
can already be achieved. The proposal would also have no detrimental impact on
parking, trees or biodiversity, or flood risk, subject to conditions.
1.8 Taking all relevant matters into account and giving due regard to local residents’
objections (including the petitions against the application), it is concluded that the
proposal complies with the Development Plan and no material considerations
indicate that a contrary decision should be taken. The planning application is
therefore recommended for approval subject to the conditions set out in Appendix
1.
2 The Site and Locality
2.1 The application site comprises a detached , single storey residential bungalow
located on the south ern side of St. George’s Dr ive, close to the junction with
Copthall Road West. The property is of brick construction with a hipped tile roof,
and is characterised by a feature gable pr ojection to the front elevation. The
property benefits from an existing single garage to one side and single storey
extension to part of the rear, both of whic h have flat roofs. The property has off-
street parking to the front, including two dropped kerbs, and garden to the rear.
2.2 The site lies within a residential area, wi th St. George’s Drive characterised by a
mixture of single and two storey detac hed dwellings. The neighbouring property
to the west, no. 72, is also a bungalow. To the east, the application site borders
onto the gardens of properties facing onto Copthall Road West, which are two
storey and either semi-detached or detached. The gardens of these properties are
notably shallower, at approximately 9 to 10m in depth.
2.3 Many properties in the vicinity have been extended or altered in some form,
including roof conversions and the installation of dormers, and rear extensions.
Along St. George’s Drive,
there are numerous examples of large and bulky roof
extensions to properties in the street sce ne, including box dormers to both side
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roof slopes of nearby dwellings. Many of these such additions have been achieved
via the provisions of Permitted Development, i.e. not required planning permission.
2.4 The site is not located within a Conse rvation Area or Area of Special Local
Character. It falls within Flood Zone 1, but within a Critical Drainage Area. There
are no other relevant constraints.
Figure 1: Location Plan (application site edged red)
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Figure 2: Front Elevation of Application Property
Figure 3: Rear Elevation of Application Property
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Figure 4: Front and West-Facing Side Elevation of Application Property
Figure 5: East-Facing Side Elevation of Application Property
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Figure 6: No. 91 St. George’s Drive (Opposite the Application Site)
Figure 7: Example of some side Dormers typical of St. George’s Drive
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Figure 8: Example of similar side dorm er to bungalow along St. George’s
Drive
3 Proposal
3.1 The application proposes the construction of a single storey rear extension and
conversion of the roof to habitable acco mmodation, including dormers to both
sides and a hip-to-gable extension to the rear. As part of the proposal, the existing
garage roof would also be altered, to include a dummy pitch, in addition to the
expansion of the raised patio area to the rear and removal of a chimney.
3.2 The proposed rear extension would have a depth of 4m, and height of 2.85m from
natural ground level. It would adjoin to the side of the existing rear extension,
which is slightly larger at approximately 4.6m in depth. The dormers would run for
much of the side elevations of the prop erty, each measuring approximately 6.8m
in length.
3.3 As mentioned in the Executive Summary, materially similar extensions to the
property have already been previously granted under the provisions of Permitted
Development, i.e., demonstrated to show that they would not require planning
permission. This has included a single storey rear extension, of similar depth and
siting to that proposed, granted under prior approval application (ref:
79535/APP/2025/1625), and the conversion of the roof to habitable
Hillingdon Planning Committee – 4th June 2026
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accommodation, including dormers to both sides and a hip-to-gable extension to
the rear, granted under a lawful development certificate (ref:
79535/APP/2025/1632). The permitted plans for these two
previous applications
are shown in the following section.
3.4 The proposed scheme expands on these previous applications, making additional
alterations which hence have consequently required planning permission to be
sought. Following amendments made to the application, these alterations include:
- Enlargement of the size of the west- facing dormer, so that it reflects the box
design of the east-facing dormer (this enlargement means the scheme
would now exceed the maximum 50 sqm. volume limit allowed under
Permitted Development)
- To the rear, the dormers are no longer set in from the gable edge of the
roof, and include an additional window.
- Increased height of the rear extension by approximately 0.25m (the depth
(4m) and siting would remain as approved under 79535/APP/2025/1625).
3.5 The east-facing dormer, facing the gardens of properties along Copthall Road
West, is largely unchanged from the granted 79535/APP/2025/1632 application.
Though no longer set in from the rear ga ble edge of the roof, as was originally
granted, the overall length and bulk of this dormer remains materially unaltered
from the previously granted certificate of lawfulness application.
3.6 The proposed raised patio and garage roof alterations are new to this application
and have not previously been sought. Following amendments to the scheme, the
proposed raised patio has been reduced to a maximum height of 0.3m. As part of
the amendments made, an originally proposed hip-to-gable extension to the front
roof slope, which would have made the side dormers longer , has also been
removed from the scheme.
3.7 In accordance with the description above, the revised proposed drawings, which
are put forward to the Committee for consideration, are shown in the Figures
overleaf, along with the ‘existing’ drawings – how the property appeared prior to
any works commencing on site.
3.8 It should be noted that the existing flue that has been installed to the east-facing
side elevation is not included on the proposed plans and does therefore not form
part of this application. Should the appl ication be approved, this feature would
require separate regularisation,
as it is currently without consent – either via the
submission of a lawful development certificate, planning permission, or
enforcement action if necessary.
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Figure 6: Existing Drawings (please note – a larger version of plan can be found
in the Committee Plan Pack)
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Figure 7: Proposed Drawings (as Amended) (please note – a larger version of
plan can be found in the Committee Plan Pack)
4 Relevant Planning History
4.1 A full list of the planning history relating to the property can be found in Appendix
2.
4.2 As mentioned, it is material to note that both a Certificate of Lawfulness (ref:
79535/APP/2025/1632) – for the conversion of the roof space to habitable use,
including dormers to both side elevations and hip-to-gable extension to the rear –
and a prior approval application (ref: 79535/APP/2025/1625) – for the construction
of a single storey rear extension of 4m depth and 2.6m height – have been
previously granted at the site. These pr evious applications sought confirmation
from the Local Planning Authority that their respective developments would not
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require planning permission, given t he allowances of national Permitted
Development legislation. These previous schemes are shown in the figures below.
4.3 The proposed scheme expands on these previous proposals, making additional
alterations which hence have consequently required planning permission to be
sought. Following the amendments made, these alterations include:
- Enlargement of the size of the west- facing dormer, so that it reflects the box
design of the east facing dormer.
- To the rear, the dormers are no longer set in from the gable edge of the
roof, and include an additional window.
- Increased height of the rear extension by approximately 0.25m.
4.4 Based on what has already been granted under the previous applications (and for
which planning permission was not necessary), in effect it is only these above
alterations that the application seeks approval for, in addition to the garage roof
changes and patio enlargement.
4.5 It is noted that works to the property have commenced since the approval of
79535/APP/2025/1632 and 79535/APP/2025/1625. Members are reminded that
this application seeks approval for what is shown on the proposed plans only,
rather than what has
necessarily been built ‘on site’ . Should the application
therefore be approved, this would not grant permission for the built development
as it appears ‘on site’, as certain aspects would remain unlawful, namely the:
x rear patio (the proposal is for a raised patio of maximum 0.3m in height –
what has been built on site exceeds this height)
x west-facing dormer (the proposed dormer is different to what has been built
on site. What has been built on site is also not Permitted Development as
it is not set in from the gable edge of the rear roof Currently , it therefore
does not comply with the proposed scheme or previously approved
79535/APP/2025/1632 certificate).
Accordingly, if permission were to be granted, a condition is recommended to be
included to ensure the necessary alterations are made to the above aspects,
within a 6-month time frame, or otherwise demolished. This would ensure that the
unlawful parts of the development that have been built on site , as above, would
be regularised in line with the proposed plans, within a reasonable but enforceable
timeframe.
4.6 Separately, as previously mentioned, th e existing flue that has been installed to
the east -facing side elevation is not included on the proposed plans and does
therefore not form part of this application. Should the application be approved, this
feature would require separate regularisation
as it is currently without consent –
either via the submission of a lawful development certificate, planning permission,
or enforcement action if necessary.
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Figure 8: Previously Granted Roof Alterations (Permitted Under
79535/APP/2025/1632)
Figure 9: Previously Granted Rear Extension (Permitted Under
79535/APP/2025/1625)
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5 Planning Policy
5.1 A list of planning policies relevant to the consideration of the application can be
found in Appendix 3.
6 Consultations and Representations
6.1 14 neighbouring properties, as well as the Ickenham Residents Association, were
originally consulted on the application on 23.01.2 6, with the consultation period
expiring on 13.02.2025. Following amendments made to the application, a second
neighbour consultation period was under taken for 14 days, expiring on
12.05.2026.
6.2 At the time of publishing this report, altogether:
- Three petitions, with a total of 181 valid signatures were received in
objection to the proposal.
- 97 representations, from 54 different individuals, were received, in
objection to the proposal.
6.3 Representations received in response to public consultation are summarised in
Table 1 (below).
Table 1: Summary of Representations Received
Representations Summary of Issues
Raised
Planning Officer
Response
Petitions of 181
total valid
signatures have
been received
against the
application
I. Impact on the
character of the area;
overdevelopment.
II. Impact on neighbour
amenity (Loss of
privacy, loss of
daylight/
overshadowing,
non-
compliance with 45-
degree test)
III. Increased Flood Risk
IV. Inconsistent
measurements
Discussed within
paragraphs 7.2 - 7.26 of
this report.
Discussed within
paragraphs 7.27 - 7.61 of
this report.
Discussed
within
paragraphs 7.66 – 7.69 of
this report.
The application seeks
approval for what is shown
on the plans only. Where
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V.
Retrospective; built
without permission.
VI. Increased risk of
vermin from the
development
this deviates from what
has been built ‘on site’, this
w
ould be resolved through
conditions and planning
enforcement, where
necessary.
Construction commenced
following the granting of
applications
79535/APP/2025/1632
and
79535/APP/2025/1625;
however, the development
has not been carried out in
accordance with the plans
approved. As such,
planning permission is now
required for parts of the
development.
The planning
system does not operate
on a punitive basis, and
the retrospective nature of
the application is not in
itself, a material planning
consideration
. The
proposal has therefore
been assessed on its
planning merits.
The application relates to
householder additions to
an existing property. In
terms of the planning
assessment, no concerns
regarding vermin would
therefore be raised.
If the
construction process has
brought about vermin
issues, this would be a
matter for the Council’s
Environmental Health
Team to investigate and
resolve.
97 individual
letters of objection
I. Harm to character
and appearance of
Discussed within
paragraphs 7.2 - 7.26 of
this report.
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have been
received
the site / area;
overdevelopment –
cumulative impact;
out of keeping /
incongruous/
development far
exceeds the footprint
of the original
bungalow
II. Impacts on neighbour
amenity; loss of
privacy / overlooking;
loss of light /
overshadowing;
overbearing
Discussed within
paragraphs 7.27 - 7.53 of
this report.
III. Highway and parking
concerns; highway
safety.
Discussed within
paragraphs 7.57 - 7.61 of
this report.
IV. Concerns over
drainage of surface
water / rainwater; flood
risk.
Discussed within
paragraphs 7.66 - 7.69 of
this report.
V. Inaccuracies in the
plans; plans don’t
match the build
The application seeks
approval for what is shown
on the plans only. Where
this deviates from what
has been built ‘on site’, this
w
ould be resolved through
conditions and planning
enforcement, where
necessary.
VI. Construction has
started without
consent; does not
have permission;
started without
approval
Construction commenced
following the granting of
applications
79535/APP/2025/1632
and
79535/APP/2025/1625;
however, the development
has not been carried out in
accordance with the plans
approved. As such,
planning permission is now
required for parts of the
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development. The planning
system does not operate
on a punitive basis, and
the retrospective nature of
the application is not in
itself, a material planning
consideration. The
proposal has therefore
been assessed on its
planning merits.
VII. Concerns about
construction impact;
improper conduct of
builders
Contractors are required to
adhere to all relevant
regulations to limit impacts
on neighbours, including
hours of construction
. The
Council recommends an
informative reminding the
applicant of their
construction noise and
hours obligations
which are
allowed under The Control
of Pollution Act 1974, the
Clean Air Acts and other
related legislation.
These matters are
however not material to the
planning assessment of
the proposal, and where
breaches have occurred,
this would be a matter for
the Council’s
Environmental Health /
Noise
Nuisance teams to
investigate and resolve.
VIII. Vermin; potential
contamination of soil
The application relates to
householder additions to
an existing property. The
site does not fall within
contaminated land. In and
of itself,
as mentioned
above no concerns
regarding vermin would
therefore be raised.
Allegations have been
raised regarding the use of
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builder’s waste / rubble as
a means to raise the height
of the patio. Should the
application be approved,
and potentially hazardous
internal debris then used to
raise the patio (following
the alterations required),
this would be a matter of
investigation for the
Council’s Environmental
Health team.
IX. Previous application
removed from public
scrutiny – concerns
how these two
previous applications
were handled.
The previous application
ref: 79535/APP/2025/1632
was for a Certificate of
Lawfulness. Neighbours
are not consulted on such
certificates (and there is no
statutory requirement to
consult neighbours)
as
representations cannot be
taken into consideration –
the assessment for such
certificates is simply
whether or not the
development complies with
nationally set
Permitted
Development criteria, and
subsequently whether or
not it would require
planning permission.
The
previous certificate was
granted, confirming
that
the development it
proposed would fall within
the remit of Permitted
Development, and would
have therefore not required
planning permission.
The previous application
ref: 79535/APP/2025/1625
was
a prior approval
application for which
neighbours were consulted
in accordance with the
legislative procedure. The
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Prior Approval application
had taken account of the
comments from the
immediate neighbours in
its assessment on amenity
grounds
.
X. Air quality – flue /
chimney
Discussed within
paragraph 7.65 of this
report.
XI. Potential conversion to
HMO
This application is for
additions to an existing
family dwellinghouse
.
Following the introduction
of the Council’s Borough-
wide Article 4 Direction,
any
conversion of the
property from a single
dwelling to HMO would
require the prior consent of
the Local Planning
Authority.
XII. Disregard for the
planning rules and it
would set a precedent
for future
developments
Each application is
assessed on its own
individual merit. The
planning process is not a
punitive one, and in
assessing the merits of a
proposal, whether the
proposal is retrospective or
has been started without
permission, does not hold
weight in the planning
assessment.
XIII. Inaccuracies in the
information submitted
e.g. more than two
bungalows on the
street (includes
Planning Statement
and Orientation of the
properties)
Inaccuracies are noted in
the planning statement.
The Case Officer is aware
of these and as such these
have not impacted the
assessment of the
application. The Planning
Statement indicates that
planning permission is also
being
sought for the flue,
however as above it is not
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shown on the proposed
plans, nor included in the
development description.
Accordingly, for the
avoidance of doubt, the
flue does not form part of
this application.
7 Planning Assessment
Principle of Development
7.1 The application relates to an existing re sidential property sited within an urban
location, outside of the Green Belt. In su ch locations, extensions and alterations
to residential properties would be cons idered acceptable in principle, subject to
complying with all relevant Development Plan Policies and material considerations
as set out below. Additionally, there is already a fall-back in place for the proposed
roof and rear additions, given what has already been granted at the site under the
previous applications (demonstrating what could be built without requiring
planning permission).
Character and Appearance
7.2 Policy BE1 of the Hillingdon Local Plan: Part One Strategic Policies (2012) seeks
a quality of design in all new development that , inter alia , enhances and
contributes to the area in terms of form, scale and materials, respects the local
character, and is appropriate to the identity and context of the townscape.
7.3 Policy DMHB 11 of the Hillingdon Local Plan: Pa rt Two - Development
Management Policies (2020) advises that all development will be required to be
designed to the highest standards and incorporate principles of good design.
7.4 Policy DMHD 1 requires that alterations and extension of dwellings would not have
an adverse cumulative impact on the character and appearance of the street
scene, and should appear subordinate to the main dwelling.
7.5 With regard to roof extensions, Policy DMHD1 requires that:
- Roof extensions should be located on the rear elevation only, be subservient to
the scale of the existing roof and should not exceed more than two thirds the
average width of the original roof. They should be located below the ridge tiles of
the existing
roof and retain a substantial element of the original roof slope above
the eaves line.
7.6 With regard to rear extensions, Policy DMHD1 requires that:
- Single storey rear extensions to detached houses with a plot width of 5 metres
or more should not exceed 4 metres in depth.
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- Flat roofed single storey extensions should not exceed 3 metres in height.
Site Context
7.7 The site lies within a residential area, characterised by a mixture of single and two
storey dwellings. Many properties in the vicinity have been extended in some form,
including roof conversions and the installation of dormers, and rear extensions.
7.8 As existing, there are numerous examples of large and bulky roof extensions to
properties in the street scene, including box dormers to both side roof slopes of
nearby dwellings. Many of these such additions have been achieved via the
provisions of Permitted Development, i.e. not required planning permission.
Examples include nos. 41, 67, 69, 73 St. George’s Drive, and no. 91 opposite the
application site.
Images of nos. 91, and 67 and 69, can be seen within Figures 6
7 and 11 of this report respectively.
Figure 10: Application site (pre-develop ment) with neighbours properties
along Copthall Road West to the left
Roof Extension Proposed
7.9 As mentioned previously, the site has already had a Certificate of Lawfulness and
prior approval application granted for a rear hip -to-gable extension and side
dormers, and single storey rear extension respectively. This is a significant
material considera
tion as it demonstrates a viable fall-back position of what could
be built at the site, and indeed what could be built without even requiring planning
permission. What has been built on site currently is comparable (though not
identical) to these two previous applications.
7.10 In effect, Members are advised it is only therefore the deviations from the previous
schemes that can be assessed, and whether these deviations in and of
themselves result in any significant harm to the character and appearance of the
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property and surrounding area, beyond what has already been granted. This is
considered below.
Figure 11: Examples of existing roof extensions along St. Georges Drive
which contribute to the variation in the roof form
7.11 In terms of streetscene analysis, it was cl ear from the site inspection carried out
and the above images, that there are various extensions to the sides and rear of
the roof that are prevalent along the street. The neighbouring properties along
Cophall Road West have several rear dormer roof extensions built largely through
permitted development that can be visible from several view points on St Georges
Drive. The housing tenure along St. Georges Drive is a mixture of both bungalow
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and two storey dwellings. There are se veral notable properties that have
implemented side roof dormers including No 72 St George Drive (neighbour
property). From the images (figures 6-8 and figures 10-12), it demonstrates that
there is no singular or uniform roof form along St George’s Drive, with a noticeable
variation in the scale, form and design of roof alterations and side dormer additions
throughout the wider street.
Figure 12: Further examples of the variation in side dormers along
St.Georges Drive
7.12 The streetscene analysis demonstrates that there is no singular or uniform roof
along St George’s Drive, with a noticeable variation in the scale, form and design
of roof alterations and side dormer addi tions throughout the wider street. The
examples illustrated show a range of differing roof profiles, side extensions and
dormer configurations which collectively contribute to a more varied and evolving
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character rather than a rigidly consistent appearance. In this context, the proposed
side dormers would not appear isolated or incongruous within the streetscene and
are considered to reflect the established pattern of domestic alterations visible
along the road.
7.13 Furthermore, it is also noted that the side dormers proposed under the current
application are not materially dissimilar in scale, form or appearance along the
front elevation to those previously approved under the lawful development
certificate. The comparison of both the previously granted front elevation through
lawful certification and the current application is shown in figure 13.
Figure 13: Comparison of roof extensions: lawful certificate granted
79535/APP/2025/1632 (Top image) and the current side dormers proposed
(Bottom image)
7.14 Whilst minor design amendments are proposed, these would not result in a
significantly different visual outcome when compared to the fallback scheme
already established as acceptable. The current proposal would therefore maintain
a comparable relationship with the host dwelling and surrounding streetscene
7.15 Similarly, along the eastern elevation facing on Copthall Road West, the amended
plans received during the assessment reduced the overall size of the dormer in
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line with what was approved under the lawful certificate previously granted. This
is also demonstrated in figure 14 below.
Figure 14: Comparison of Previously Granted East-Facing Dormer lawful
certificate 79535/APP/2025/1632 (Top Image) and Proposed East- Facing
Dormer (Bottom Image)
7.16 In terms of the roof alterations, as shown in Figure 14, the proposed dormer to the
east-facing elevation would be in effect identical to that granted under
79535/APP/2025/1632 in terms of size and siting. As such, there would be no
greater impact on the character and appearance of the dwelling and surrounding
area resulting from this aspect when co mpared with what has already been
granted consent (and indeed what can be built without requiring planning
permission).
7.17 The dormer to the west-facing elevation would be enlarged in size compared to
the 79535/APP/2025/1632 application, however, would remain of a similar overall
length and siting to what was previously granted. Whilst of slightly greater overall
bulk (the proposal would ‘fill out’ the previously granted dormer), the dormer would
match the size and scale of the east faci ng dormer, creating a level of balance.
Hillingdon Planning Committee – 4th June 2026
PART 1 – Members, Public & Press
Furthermore, like the east-facing dormer, it would continue to be appropriately set
down from the roof ridge, set up from the eaves and set back from the front
elevation. As such, and when compared against what has already been granted
consent, again it is
not considered that this addition would result in any greater
level of harm to the character and appearance of the property or street scene than
the previous scheme. This is especially th e case given the context of the street
scene, where numerous other
large side dormers , to both flank elevations of
properties, are evident; accordingly these features would not look out of keeping
within the street scene.
7.18 The hip-to-gable extension has also largely already been established under the
previously approved application ref. 79535/APP/2025/1632. Under the current
proposal, the side dormers would no longer be set in from the rear gable and,
together with the enlargement to the west-facing dormer, this would result in a
somewhat greater sense of bulk when viewed from the rear. Whilst this
relationship is acknowledged to be less refined in design terms than the
previously approved scheme, it is noted that these views would be experienced
predominantly from private vantage points rather than within the public
streetscene. As such, the visual impact arising from this aspect of the proposal is
considered to be limited and would not result in a level of harm sufficient to
warrant refusal of the application. It must also be added that the building
materials and overall quality of the brickwork and roof slates would also reduce
the visual impact. On balance, this element of the scheme is therefore
considered acceptable.
7.19 Overall, in terms of the roof alterations, the scheme would remain materially and
visually comparable to that already approved under 79535/APP/2025/1632,
particularly when viewed from the public domain. The bulk of the further alterations
from 79535/APP/2025/1632 would be to the rear of the property, whereby they
would not be visible from the street sce ne, whilst the side dormers themselves
would be of an overall size, scale and bulk which is consistent with other similar
conversions along St. George’s Drive, set back from the front elevation to a similar
extent, and in terms of depth and siting, remaining largely identical to those
granted under 79535/APP/2025/1632. Despite the additions, the property would
continue to read as a bungalow, consistent with its existing form, with no increase
to the existing ridge height proposed. Additionally, the proposed materials would
replicate those used in the existing dwelli ng, continuing to match with the wider
street scene.
Single storey rear extension and garage roof alteration
7.20 In terms of the rear extension, this remains of an identical depth (4m) and footprint
as the rear extension already granted under 79535/APP/2025/1625 , however is
now proposed to be 0.25m higher (2.85m, from 2.6m). Policy DMHD 1 of the
Hillingdon Local Plan: Part Two (2020) advises that single-storey rear extensions
to detached dwellings should not normally exceed 4 metres in depth, as measured
from the original rear wall with a maximum height of 3 metres for developments
with a flat roof.
Hillingdon Planning Committee – 4th June 2026
PART 1 – Members, Public & Press
7.21 At 4m, the depth of the rear extension would comply with the requirements of
Policy DMHD 1, as would the height, despite the minor increase. Furthermore,
the extension would be of a conventional design, with the flat roof matching with,
and integrating into, the existing rear extension, and given the lesser scale and
flat roof it would continue to appear as subservient to the main dwelling. Overall
this element would appear as proportionate and of an acceptable appearance
utilising matching materials to the
existing property. As such, the rear extension
would not be harmful to the character of the existing property or surrounding
area – and certainly to no greater extent than the rear extension for which
consent has already been granted.
7.22 In terms of the alteration to the exis ting garage roof, this would be for purely
aesthetic reasons, involving the addition of a modest dummy pitched element to
the front portion of the garage. The roof element would complement the hipped
design of the front of the property and be of an appropriate size and scale that
retains the subservience of the garage. As such, no concerns are raised with
regards to this aspect. The patio and removal of the original chimney are also
considered to be acceptable in character/appearance terms.
Patio/Raised terrace
7.23 The proposed patio has been subject to amendment during the course of the
application to reduce its height to approximately 0.3 metres above ground level.
As a result, the patio would now present as a low-level, ground-related feature
that integrates more comfortably within the rear garden setting, rather than
appearing as a raised or engineered platform. The stepped arrangement and
limited projection from the host dwelling ensure that the patio remains visually
subservient and proportionate, with its form closely reflecting typical domestic
garden layouts.
7.24 In design terms, the revised patio would not appear as a dominant or visually
intrusive addition when viewed in the context of the host property, instead
reading as a modest extension of the internal living space into the garden. Whilst
the relationship with neighbouring plots is acknowledged given the corner siting,
the reduced height and simplified form materially lessen its visual presence,
particularly when viewed from surrounding areas.
The raised terrace height
would also be in line with what would be allowed under permitted development.
A condition is proposed to ensure that the current height of the platform is
reduced in line with the permitted development requirement prior to its usage.
The proposal is therefore considered to achieve an acceptable design response
that is consistent with the character of a residential garden environment.
Design (Conclusion)
7.25 Overall, when assessing the scheme as a whole, the proposal is considered to
represent an acceptable form of development that responds appropriately to the
character and appearance of the host dwelling and the surrounding area. It is
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acknowledged that certain aspects of the rear elevation design, particularly the
side dormers relationship with the rear roof form depart slightly from the more
typical design approach to roof altera tions. However, in th is instance, these
variations are limited in their visual impact and are not considered to result in a
harmful or incongruous form of develo pment especially given the fallback design
that has already been approved through a lawful certificate.
7.26 When taking into account the previous schemes and surrounding context of
neighbouring developmen t, in it’s entirely it is overall not considered that the
proposal would result in any significant harm to the character and/or appearance
of the dwelling or surrounding area beyond what has already been granted
consent. As such, subject to conditions over materials, and the regularisation of
existing unlawful works , the application is considered acceptable in
character/appearance terms.
Residential Amenity
7.27 Policy DMHB 11 of the Hillingdon Local Plan: Pa rt Two - Development
Management Policies (2020) seeks to ensure that development proposals do not
adversely impact on the amenity, daylight and sunlight of adjacent properties and
open space.
7.28 Policy DMHD 1 of the Hillingdon Local Plan: Part Two - Development Management
Policies (2020) states that planning applications relating to dwelling alterations
and extensions will be required to ensure that a satisfactory relationship with
adjacent dwellings is achieved and there is no unacceptable loss of outlook to
neighbouring occupiers.
7.29 The application site borders no. 72 St. George’s Drive, a single storey bungalow,
to the west. To the east, the site borders the gardens of properties facing onto
Copthall Road West, specifically nos. 81a to 89 (odds). These properties are two
storey with shallow gardens (approx. 9/10m in depth).
7.30 Similarly mentioned in the previous section, Members are reminded that given the
already granted Certificate and prior appr oval applications, with regard to the
dormers, rear hip-to-gable extension and rear extensio n, it is effectively only the
changes from these previous two pr oposals which can be considered, and
whether these changes (and any other additions, such as the rear patio) in and of
themselves result in any significant harm to the amenity of neighbours, beyond
what has already been granted. This is considered below.
72 St. George’s Drive
7.31 In terms of no. 72 St. George’s Drive, this dwelling is staggered owing to the bend
in the road, such that its front elevatio n is set behind that of the application
property’s, and rear elevation beyond. Given their siting, the east -facing dormer
and rear extension would have no impact on this property beyond the existing
relationship.
Hillingdon Planning Committee – 4th June 2026
PART 1 – Members, Public & Press
7.32 In terms of the west-facing dormer (facing 72 St. George’s Drive) and rear hip-to-
gable extension, these aspects have been modified from the previous granted
Certificate, with the dormer in particular being increased in bulk (but remaining of
a similar length). Notwithstanding this, neither of these aspects would increase the
footprint of the property,
nor increase its overall height. As such and given the
difference in siting of both properties, neither of these aspects would result in any
discernible loss of light or outlook with regard to this neighbour’s habitable
openings.
87 to 95 St. George’s Drive
7.33 The residential properties opposite the site (Nos.87-95), including those in the
vicinity of No. 74 St. George’s Drive, have been considered. These properties are
located on the opposite side of the public highway, with separation distances
consistent with the prevailing street pattern. Given this relationship,
the proposed
development would not result in any material loss of privacy, outlook, or give rise
to an overbearing impact. Accordingly, no unacceptable harm to the residential
amenity of these occupiers is identified.
81a to 83 Copthall Road West
7.34 In terms of Nos. 81A to 83 Copthall Road West, the rear elevations of these
properties face towards the application site. However, these properties are
characterised by larger distance which reduces the overall impact on their
amenity. As seen on the site location plan, this results in a relationship where the
proposed development is positioned beyond the primary amenity areas of these
neighbouring occupiers, with a clear and appreciable separation distance
maintained. In addition, the orientation and layout of the respective plots are
such that the rear elevations of Nos. 81A and 83 do not directly align with or
project towards the flank elevation of the application property, further reducing
the perception of proximity.
7.35 The impact to the garden of no. 81a would be within tolerable limits, given that
the separation distance from the first floor rear windows to the flank wall of this
neighbour would be no less than 21m, which is compliant with the back-to-back
distances specified in the Local Plan (minimum 21m). Whilst the distance
between the garden of No 83 Cophall Road West is shorter, the level of
overlooking would be no greater than can what already be achieved under the
granted 79535/APP/2025/1632 application. Consequently, the proposed
development would be experienced within a broader garden context rather than
as an immediate or enclosing presence. On this basis, it is not considered that
the proposal would result in any material loss of light, outlook or undue sense of
overbearing impact to these neighbouring properties.”
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85 to 89 Copthall Road West
7.36 The proposed rear extension would be sited largely between the rear gardens of
Nos. 85 and 87, positioned behind the existing shared garage/outbuilding which
runs along the mutual boundary. It is noted that prior approval has already been
granted for a 4m deep rear extension at this location with a height of 2.6m. The
current proposal seeks an extension of comparable depth and siting, with a
modest increase in height to 2.85m. This increase of approximately 0.25m is
limited in scale and remains within the parameters generally supported by local
policy, which allows flat roof extensions up to 3m in height. This fallback position
is an important material consideration in assessing the acceptability of the
proposal.
7.37 Officers have undertaken a site visit to Nos. 85 and 87 and the relationship is
illustrated within Figure 15. The image on the left, taken from No. 85,
demonstrates that whilst the extension would be visible above the existing
single-storey outbuilding, the majority of the outlook across the garden would be
retained, with the proposed roof form appearing as a modest addition above the
established boundary treatment. The image on the right, taken from No. 87,
similarly shows that the extension would be read in the context of existing built
form along the boundary, with limited additional visual intrusion over and above
what had previously been approved through a lawful certificate which has been
highlighted within figure 14.
Figure 15: Photos taken from neighbouring properties at Nos 85 & 87
Copthall Road West
7.38 Having regard to the separation distances, the depth of the adjoining rear
gardens, and the presence of intervening structures, it is not considered that the
proposed rear extension would give rise to a material loss of outlook, undue
Hillingdon Planning Committee – 4th June 2026
PART 1 – Members, Public & Press
sense of enclosure, or overbearing impact to the occupiers of Nos. 85 and 87.
The limited increase in height over the fallback position would not materially alter
this relationship.
7.39 As illustrated within Figure 14, which prov ides a direct comparison between the
previously granted lawful development ce rtificate and the current proposal, the
east-facing dormer would be comparable in terms of overall scale, siting and
projection. The visual comparison demonstrates that there is no material increase
in built form along this flank elevation when viewed from Nos. 85 and 87. As such,
the extent of development facing these neighbouring properties would not be
materially greater than that which
could already be implemented under permitted
development
7.40 In terms of bulk and form, the proposed east-facing dormer and hip-to-gable
extension would be read in the context of the existing and fallback roof form, as
demonstrated in Figure 14, and the established pattern of development along the
terrace. Whilst the development would introduce additional built form at roof
level, it would not project to a degree that would appear unduly dominant or
visually intrusive when viewed across the separation distances involved.
Furthermore, the hip-to-gable element extends the roof form vertically rather
than towards neighbouring properties, thereby limiting any additional sense of
enclosure at garden level.
7.41 In terms of privacy, the application proposes new side and rear windows at first
floor level following the addition of the dormers and hip-to-gable extension. At
ground floor level, there would be no material difference compared to the
existing arrangement in terms of openings. With regard to overlooking, the
fenestration proposed within the dormer is consistent with that previously
approved under the lawful development certificate, including the use of obscured
glazing where necessary to prevent direct views.
7.42 In terms of the first floor side openings, given the context of surrounding plots,
there is significant potential for these windows to result in direct overlooking for
the adjacent neighbours. To the east, the window would look directly into the
garden of no. 87 Copthall Road West, and to the west these windows, given their
height and siting, would face onto the existing roof openings of no. 72 St. George’s
Drive, resulting in a loss of privacy for these neighbours. This would be
unacceptable, and as such i t is recommended that all proposed side windows
above ground floor level are conditioned to be obscurely glazed and non-opening
below 1.7m floor level. This would be an acceptable compromise in this instance,
preventing any overlooking/loss of privacy from these windows, whilst the amenity
of the occupiers would not be unduly impacted given that these side windows only
serve non
-habitable rooms and spaces. As such, provided the recommended
condition is complied with, the side openings would not result in any undue
overlooking or loss of privacy. Nevertheless, to ensure the privacy of the adjacent
neighbours to each side long
-term, it is also recommended to remove permitted
development rights for any further side openings above ground level and restrict
access to the roof of the rear extension for maintenance purposes only.
Hillingdon Planning Committee – 4th June 2026
PART 1 – Members, Public & Press
7.43 To the rear, the hip-to-gable extension, combined with the dormers, would
additionally introduce two windows to the property at first floor level. Though the
primary outlook would be to the applicant's own garden area, it is acknowledged
that
given the additional height, a level of oblique overlooking would be introduced
to surrounding neighbouring gardens.
7.44 It is acknowledged that these would afford views over the application site’s rear
garden and towards neighbouring properties. Notwithstanding this, it is noted in
the previous 79535/APP/2025/1632 granted scheme, that a window was
proposed to be installed to the rear elevation at first floor level, for which, as the
certificate was granted, it was confirmed that planning permission would not be
required. This window would have afforded a materially similar level of
overlooking across neighbours as that now proposed, when considering its size
and siting.
7.45 The lawful development certificate also established a fallback position whereby a
rear-facing window serving a habitable room could be installed at a comparable
level. Whilst the current proposal includes two such window openings, officers
consider that the degree of overlooking wo uld not be materially greater than that
which could already occur under the fallback position. Furthermore, the separation
distances between properties and the depth of the rear gardens are such that any
views would be
oblique views of the back end of the garden. Overall the amenity
areas closest the dwellings would be largely protected. On this basis, whilst some
perception of overlooking may arise, it would not be of a magnitude that would
result in unacceptable harm to neighbourin g amenity or justify refusal of the
application.
7.46 In terms of daylight, sunlight and overshadowing, whilst no detailed BRE
assessment has been undertaken, officers have considered the relationship
having regard to the scale, siting and orientation of the proposal. The
development would be positioned to the rear of the host dwelling and separated
from neighbouring properties by intervening garden depths of approximately 10
metres or more. The single
-storey nature of the rear extension, together with the
limited increase in height beyond the established fallback position, would not
give rise to any material loss of daylight or sunlight to neighbouring habitable
room windows.
7.47 Furthermore, given the separation dist ances involved and the position of the
development relative to adjoining gardens, it is not considered that the proposal
would result in any undue overshadowing or loss of sunlight to neighbouring
outdoor amenity spaces. Any impacts wou ld be limited and consistent with what
would reasonably be expected within a suburban residential context
7.48 In any case, in terms of overshadowing these aspects would again not increase
the footprint of the property, nor increase its overall height. As such, and given
their siting, approximately 9 to 10m away from the rear -facing habitable room
windows of these neighbours, whilst the concerns of residents are acknowledged
Hillingdon Planning Committee – 4th June 2026
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it is not considered that these additions would result in any discernible loss of light
for either neighbour given the separati on distances involved and the lack of
increase in overall height. As such, the proposal is not considered to give rise to
unacceptable impacts in terms of daylight, sunlight or overshadowing.
7.49 In terms of the garage roof, only the very front would be altered given the size and
siting of the proposed dummy pitch roof. Overall this would be a modest addition
and given the siting and context, largely behind an existing outbuilding belonging
to no. 89 Copthall Road West, no discernible impact on neighbour amenity is
envisaged with respect to this aspect.
Rear Raised Patio
7.50 In terms of the rear patio, prior to works commencing on site this was already
raised (see Figure 16), but is proposed to be expanded as part of the proposal. At
the request of the Case Officer, the proposed height of the rear patio has however
been reduced to 0.3m, which is the maximum height for which planning permission
is not required. That is to say, ther e would be no reasonable grounds to refuse a
raised patio of this height, given that such a structure could be built without
requiring planning permission, under Permitted Development.
Figure 16: Raised Rear Patio Prior to Works Commencing
Hillingdon Planning Committee – 4th June 2026
PART 1 – Members, Public & Press
7.51 Given the limited height proposed, it is not considered that the patio would result
in any significant overlooking, and in any case at 0.3m the patio could now be
constructed without requiring planning permission, as above. It is noted that works
to this aspect have already been undertaken at the site, in which a raised patio
with a height greater than 0.3m has been constructed. Members are reminded
however that their assessment is purely on what is shown on the plans only, and
not what has necessarily been built ‘on site’. In the interests of neighbour amenity,
in the event of an approval, as mentioned in Para. 4.5, so as to regularise this
aspect it would be necessary
and therefore recommended to impose a condition
to ensure the height of the patio is reduced and altered in accordance with the
plans, within a specified time frame, or otherwise required to be demolished. With
this in mind, no privacy concerns are raised
with regard to the patio. A further
condition has been recommended whereby details of screening measures be
submitted within 2 months of a decisi on. The screening measures would need to
be a minimum of 1.7m in height to mitigate overlooking. With these additional
conditions, Officers are satisfied that the patio area would not cause any privacy
concerns once the screening is installed.
Neighbour amenity (Conclusion)
7.52 Overall, whilst it is acknowledged that the proposal would result in some change
to the existing levels of neighbour amenity, these impacts must be considered in
the context of the fallback position established under permissions ref.
79535/APP/2025/1632 and 79535/APP/2025/1625. Having regard to what could
reasonably be implemented, the degree of impact arising from the current
proposal is not considered to give rise to material harm that would justify a
refusal when assessed against the development plan as a whole.
7.53 When the previous schemes are considered in their entirety, it is not considered
that the proposal would result in any mate rially greater harm to the amenities of
surrounding neighbours than that which has already been accepted through extant
consents. As such, taking into account the fallback position, there would be no
reasonable or defensible grounds to refuse the application on neighbour amenity
grounds.
Residential Amenity – Application Property
7.54 It is considered that all of the proposed rooms, and those altered by the proposed
development, would maintain an adequate outlook and source of natural light,
therefore complying with the requirements of Policy D6 of the London Plan (2021).
7.55 In terms of external amenity, Policy DMHD 1 of the Hillingdon Local Plan: Part
Two - Development Management Policies (2020) states that planning applications
relating to alterations and extensions of dwellings will be required to ensure that,
inter alia, adequate garden space is retain ed, while Policy DMHB 18 states that
developers should provide amenity space in accordance with Table 5.3 of the
Local Plan. For a f our-bedroomed dwelling as proposed, a minimum 100 sqm of
private amenity space would be required to be retained.
Hillingdon Planning Committee – 4th June 2026
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7.56 Following the proposed extensions, the property would retain rear amenity/garden
space in excess of 100 sqm and as such would comp ly with Policies DMHB 18
and DMHD 1.
Highways and Parking
7.57 Policy DMT 6 of the Hillingdon Local Plan: Part Two - Development Management
Policies (2020) states that new development will only be permitted where it
accords with the Council's adopted parking standards, unless it can be
demonstrated that a deviation from the standard would not result in a deleterious
impact on the surrounding road network.
7.58 London Plan (2021): Policy T6.1 (Residential Parking) requires that new
residential development should not exce ed the maximum parking standards as
set out in Table 10.3 of the document. As proposed, for a house with four
bedrooms in this location
(PTAL 1a) , this would equate to a maximum of 1.5
spaces.
7.59 In this instance, whilst the existing garage is not of the sufficient dimensions to
count towards the property’s off-street parking provision, the existing hardstanding
to the front of the property is already sufficient to accommodate two vehicles.
7.60 The proposed development would make no alterations to the existing front
hardstanding or accesses. Whilst the off-street parking availability would therefore
marginally exceed the limits specified in the overriding London plan, this would be
acceptable in this instance given that the proposal represents no change from the
existing arrangement, and no enlargement would be required as per the limits of
this Policy.
7.61 To this extent, the proposal would not raise any measurable parking or highway
safety concerns.
Biodiversity and Ecology
7.62 Whilst as a householder application the proposal would be exempt from national
biodiversity net gain requirements, this would not override Local Policy
requirements with respect to mitigation for any losses of site biodiversity or impact
on existing
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