Islington architects | Residential architect projects

At GOAStudio London residential architecture we have extensive experience with working with the Islington planning department and we are familiar with all the relevant planning policies that might apply for your home project. Please see below links to some of our Islington residential architect projects.

Your brief requirements, the setting of the property, and the immediate context of the property are some of the factors that will determine what home alterations the Islington planners will be prepared to allow. We will advise you about what is reasonable to expect to get approval, what might be tricky but possible, and what most likely the planners will say no to.

According to the Islington Council residential design guidance (Urban Design Guide, Supplementary Planning Document, January 2017) these are some of the key considerations that will determine the outcome of your planning application. Below we have copied and highlighted extracts of the most relevant current policy and advice for your home project.



Architect designed mansard roof extension Finsbury Park Islington N7 Kitchen e1582379059483 Islington residential architect projects
2. Angel Islington EC1 Listed house extension Kitchen rear extension internal views 1 Islington residential architect projects
Architect designed house extension Highbury Islington N5 Dinning and living areas Islington residential architect projects
Architect designed kitchen and roof house extension Arsenal Islington N5 Rear garden photo 1 e1582379763221 1 Islington residential architect projects
Angel Islington N1 Listed House rear extension Garden view Islington residential architect projects
 Islington residential architect projects
Architect designed penthouse extension Angel Islington N1 Side view 200x200 Islington residential architect projects
Architect designed penthouse extension Barbican Islington EC1Y Terrace and side view Islington residential architect projects
Architect designed mansard roof house extension Angel Islington N1 Bathroom design Islington residential architect projects
Kings Cross Islington WC1 – Listed Building rear flat extension – Rear elevation photo copy e1582378687858 Islington residential architect projects

Summary planning and design guide | Islington residential architect advice



The densely developed nature of the borough is based on buildings of eclectic and diverse architecture and age, which creates an exceptionally fine-grained character experienced at a human scale despite the borough’s central/inner London location. As the most densely populated local authority area in the country, there is great pressure on the borough’s green spaces to perform multiple functions.

The spatial development pattern established in the 19th century is still largely intact, with busy mixed use town centres at key junctions and arranged along the main north-south routes through the borough complemented by smaller local centres interspersed amongst largely residential neighbourhoods. These areas, in combination with scattered business centres, often in historic premises, provide important accommodation for the micro, small and medium businesses that are central to the local economy.

The majority of the borough’s land area is covered by established residential neighbourhoods, which are broadly split into two types. The first are those residential areas predominantly developed in the 18th and 19th centuries with traditional street patterns, narrow plots, and low to medium building heights in a perimeter block arrangement with leafy private gardens to the rear. The majority of such residential areas are included within conservation areas.

The second are those residential areas predominately developed in the mid-20th century with open block development and medium to tall building heights, although in recent years many of these areas have had traditional street patterns reintroduced through carefully designed estate renewal and infill programmes that sensitively increase densities. The sole large-scale new residential neighbourhood is centred on the Arsenal redevelopment.


  • Residential extensions, both above and below ground, should respect the integrity, rhythm and visual amenity of the street
  • Basements should be designed sympathetically with the host building and its surrounds
  • Garden rooms and outbuildings should retain a sufficiently large proportion of the original garden and be subordinate to the main buildings
  • Balconies should enhance the quality of accommodation and the articulation of facades
  • Proposed building technologies should be demonstrably effective and appropriate to their setting

All proposals for residential extensions and alterations should take into account bulk, height, massing, materials and proportion and how they relate to adjacent heritage assets, uses, building alignment and general treatment of setting. Where the proposal is within a Conservation Area, applicants should have reference to the guidance within the applicable Conservation Area Statement. These documents provide detailed information about each area’s significant features and guidance on how alterations and extensions should be designed to conserve and enhance the character and appearance of the particular area.


Typically, the rear elevations of Georgian, Victorian and Edwardian buildings were built with a consistent arrangement down the length of the terrace or street. While some terraces were built with a flat rear face without rear extensions, more commonly they were organised in a solid/void pattern with an extension and lightwell ‘void’ to maximise the amount of light and air reaching within the deep plans of many of the houses. Rear elevations generally have less formality than the more ordered front elevations, reflecting the fact they fulfil a private rather than a public function.

Scale, footprint and depth

Rear extensions must be subordinate to the original building; extensions should be no higher than one full storey below eaves to ensure they are sufficiently subordinate to the main building. For this reason and also in order to respect the rhythm of the terrace, full width rear extensions higher than one storey, or half width rear extensions higher than two storeys, will normally be resisted, unless it can be shown that no harm will be caused to the character of the building and the wider area. Locating an extension on the staircase side of a terraced dwelling can assist in maintaining the established rhythm of the existing rear elevation, and this also allows retention of the original windows to the principal rooms of the property.

The depth of extensions must also be carefully considered, having regard to both the impact on the amenity of neighbouring properties and the host building. This is particularly important for extensions exceeding a single storey. Excessively deep extensions can adversely impact on daylight, sunlight and sense of enclosure. The 45 degree rule is a useful reference to ensure that the scale of an extension will not have an adverse impact on amenity. If the centre of a main window on the rear elevation of the neighbouring property lies within a 45 degree angle of the end of the proposed extension on both plan and elevation, the depth of the extension is likely to have an unacceptable impact on the amenity of the neighbouring property.

Ground and lower ground extensions

Where they can be neatly accommodated, there will normally be scope for lower ground or ground floor extensions within a lightwell or beyond the line of the existing back addition providing sufficient garden space is retained to provide high quality and useable amenity space for day to day uses (for example clothes drying, dining, relaxation, gardening, children’s play) and does not result in fragmented areas incapable of supporting soft landscaping. High quality contemporary extensions are encouraged on lower floors except where conservation guidelines require extensions to conform to the design of the existing building.

Upper floor extensions

On the upper floors, the materials, detailing and form of the extension should normally be sympathetic to the terrace. Single half-width upper floor extensions above existing extensions are often acceptable providing there is a punctuating gap between the eaves height and the top of the extension. In conservation areas, extensions above two storeys in total will not normally be permitted.

Many terraces have paired additions with consistent rooflines. New extensions above these types of rear projections can disrupt the natural rhythm of rear elevations and should, therefore, be avoided. Furthermore, extensions that project out beyond the original back line of existing rear extensions above ground floor level, will normally be unacceptable where they:

  • Interrupt a consistent arrangement/rhythm
  • Inappropriately dominate the garden/the main building


Side extensions and end of terrace infill development can have a significant impact on the character of an area and its local distinctiveness. Height, scale, proportions, elevational treatment, materials as well as impact on neighbouring amenity need to be carefully considered.

On residential streets characterised by semi-detached dwellings, any proposal for a side extension between semidetached dwellings should take into account the rhythm and symmetry of the built form and the street as a whole. In limited circumstances it is possible that an extension would serve to restore that symmetry, but more often the effect is to undermine the prevailing rhythm and to dominate the existing building(s).

Nearly all Victorian/Edwardian residential terraces are characterised by a gap in the corner return that allows light and air in to the rear elevation and gardens. By allowing a glimpse of the rear gardens, these gaps also provide a soft backdrop to the street. For these reasons, this arrangement should normally be retained. Where there is an especially long gap or, outside conservation areas, an existing structure that is incongruous with the dominant character of the street, there may be scope for an infill building/extension that repairs and improves the street frontage.

Two approaches that can satisfactorily response to the character of Victorian/Edwardian terraced streets are:

  • A building that is designed so that it appears as part of an existing front wall that connects the two terraces, but nevertheless separate from the terraced buildings. The height of the new building should not rise appreciably higher than the existing wall because it will otherwise cease to fit within its context.
  • A full height building that follows the existing scale, proportions, roofline and building line of the adjacent street frontage. The acceptability of this approach will depend on the extent of the gap in the terrace and, where the gap is at the end of a terrace, the significance of the end gap to the character of the area. In practice, land ownership and site constraints often make this solution difficult to achieve. Where a building proposal fails to respond to the scale and proportions of the existing terrace, it is unlikely to be acceptable. This will be the case if its height and width are different from the existing terrace buildings.


The roofline is an important factor contributing to the rhythm and uniformity of a residential terrace or street. A typical terrace or row of detached/semidetached houses is designed with a consistent height at the front and rear. A well-defined roofline throughout therefore helps give terraces their inherent rhythm and unity.

When considering the scope for roof extensions it is necessary to consider the particular terrace within which the host building sits as well as the local context. Successful proposals will be both sympathetic to the host building and harmonise with the predominant roofline in the vicinity.

An extension that projects significantly above or alters the prevailing roofline can often disrupt the characteristic rhythm/unity and introduce features that fail to respect the scale, form, and character of the street frontage. Where a roof extension also involves raising the flank boundary parapets and chimneys this draws further attention to the addition.

In all cases, applications for roof extensions, dormers and roof lights will be assessed on merit, giving due consideration to:

  • The quality of design
  • Materials and construction proposed
  • The cumulative effect on visual amenity, unity and coherence of the street scene

On semi-detached villas, one sided extensions will normally be resisted where they undermine the symmetry of the original building. Two sided extensions on semi-detached villas and extensions above detached villas will usually only be considered where they exist elsewhere in the street on identically designed buildings.

Main types of roof extensions

Where they are acceptable in principle, roof extensions on residential terraces or villas must be restricted to a single storey. The profile and configuration of the existing extensions should normally be followed except in those cases where the existing design is considered out of character with the host building and/or the predominant building type. The following are the most common types of roof extension in Islington.

A mansard roof is a traditional type of roof that is generally not appropriate for contemporary buildings. There are two main types: flat mansard incorporating steep front and back and almost flat top (usually not acceptable in conservation areas); and traditional mansard incorporating a steep angled front and rear and shallow angled roof up to the ridge-line. Dormer windows are best suited to both types. Pitched ridge roofs are occasionally used for roof extensions instead of a mansard. They can accommodate dormer windows or skylights that follow the roof profile if outside a conservation area.

Contemporary roof extensions, with a lightweight appearance such as glass and steel, comprise a vertical frontage and flat roof that is usually well set back behind the front parapet. They are most appropriate on relatively modern buildings. Sometimes there is scope for contemporary extensions on Victorian terraces where existing contemporary extensions already exist in the terrace or on corner buildings that differ from, and provide a positive juxtaposition to, the remainder of the terrace.

Roof extensions to historic terraces should normally retain the historic parapet form and be set behind it. Particularly to Victorian/Edwardian terraces, the raising of the brickwork should be avoided, with a clear distinction between the host building and the roof extension above being maintained. Butterfly parapet profiles are a strong characteristic of rooflines in Islington and where these survive they should be retained. On terraces where one section of the consistent parapet line may have been lost, its reinstatement will be encouraged.

Party walls should follow the form of roof and should not include a 90 degree up stand projecting beyond the form of the roof extension to avoid unsightly protrusions. Chimney stacks should be retained and only raised where they will not disrupt the rhythm of the terrace.


Dormer windows are typically incorporated within pitched roofs and mansard roofs. Their design should be in keeping with the original dwelling and relate to the windows of the original house in proportion, detailing and position.

The position of dormers should take into account the composition of the windows immediately below them on the elevation. They should generally line up with and be no wider overall the windows immediately them on the elevation. As a result, the window within the dormer will be narrower than the windows on the main building. This ensures that dormers are appropriately to the host property, and serves to reinforce the architectural composition, rhythm and uniformity of the terrace. A small centrally positioned dormer can also be an acceptable approach, particularly on narrower plot widths.

The detailed design and proportions of the dormer should relate to the windows of the original house. The solid surrounds (cheeks) of the dormer should be as slender as possible; simple lead cheeks with a double hung timber sash window is often the best solution in historic buildings. Except for the window frame and cheeks, there should not be any solid face. The dormer should be positioned a clear distance below the ridge-line, significantly clear of the boundary parapets, and above the line of the eaves.

Roof lights

Roof lights should be designed with a slender profile and should, ideally, be flush with the roof covering to minimise their visual impact. As with dormers, the positioning and design of roof lights should relate to the windows of the original house so they do not crowd the roof, with an overall width no wider than the window apertures in the main façade.

When designed as per the above guidance, roof lights that follow the roof profile are an unobtrusive design feature and can be used where in locations where it is important to retain the profile of the roof slope, for example where an unbroken roofline in a conservation area precludes the use of dormer windows. However, they are generally not suitable for mansard roofs, as they would appear as a discordant feature.

GOAStudio London residential architecture and interior design is an award-winning practice, specialising in architectural services for residential projects across London.

As your local residential architect our team aims to provide a friendly and professional service for your home project.

Our approach is based on carefully considering the particular aspects of each scheme before coming up with a creative way for you to instil your unique stamp on what we do and how we do it. 

Royal Institute of British Architects (RIBA) and Architects Registration Board (ARB).

Appoint us for Islington residential architect projects in the following areas:

EC1 Clerkenwell, Finsbury, St Lukes
Angel, Barnsbury, Canonbury, Clerkenwell, Islington, Pentonville
N7 Holloway, Lower Holloway
Archway, Tufnell Park, Upper Holloway
Kings Cross

 Islington residential architect projects

For more information about the Islington planning department, policies and requirements please click the link above to be re-directed to Islington Council website.

Name and origin

More properly, it should be Islingdon, as (like Hillingdon and Wimbledon) the name denotes a hill (don), here formerly governed by a Mr Gisla. Old records call the place Giseldone (1005) and Gislandune (1062). The area was known as Isledon well into the 17th Century. []

Islington planning department

You will probably need planning permission if you want to build something new, make a major change to your home – e.g. building an extension, or change the use of your property. There are different rules depending on what you want to do and the relevant planning policy that applies to your property. At GOAStudio we have a proud record of dealing with the local authority planners and building control inspectors and we are on hand to assist with your application and successfully handle every stage of your project.

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We are creative problem solvers who will deal with any construction, planning, and design issue relevant to your home project.

GOAStudio London residential architecture limited, 86-90 Paul Street, EC2A 4NE, Hackney

GOAStudio London residential architecture limited, Chestnut Avenue South, E17 9EJ, Waltham Forest

t: 0203 984 3005

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