Rear extension drawings in Islington from £625
Angel, Highbury, Barnsbury and Holloway: Islington gives no depth in metres, and protects the pattern of solids and voids at the back of its terraces.
£625 £475 drawings + £150 survey (£625 total), no VAT to add
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The short answer
Islington’s Urban Design Guide SPD, adopted in January 2017, sets no depth for a rear extension. It says extensions should be no higher than one full storey below the eaves, that full-width extensions above one storey are normally resisted, and that the 45 degree rule shows whether a deep extension harms the neighbour. Ground-floor infills are normally acceptable. Our fee is £475 drawings + £150 survey (£625 total), no VAT to add; the council’s fee is separate.
Rear extension drawings
from £625
- Drawings
- £475
- Measured survey
- £150
- Total you pay
- £625
- VAT
- None to add
- A measured survey of the back of the house, the rear elevations along the terrace and the neighbours’ windows
- A check of your design against the terrace’s solid and void pattern, which the guide protects
- The 45 degree test in plan and elevation from the centre of the nearest neighbouring rear window
- A check of your address against Islington’s 42 conservation areas and their Article 4(2) directions
- Plans to the April 2024 validation requirements, and the route that fits submitted for you
£475 drawings + £150 survey (£625 total). A starting fee: we confirm one fixed figure after checking your address. The council’s own fee, where there is one, is paid to the council.
Get my fixed feeHow an Islington rear extension runs
Terrace pattern
We read the back of your terrace for returns, lightwells and gaps, since the guide tests the rhythm.
Survey
We measure the back, the garden and the neighbours’ windows.
Design
You choose height and depth, with the route and risk of each written down.
Draw and submit
We prepare the pack to the April 2024 requirements and submit it.
What the Urban Design Guide says about the back of a terrace
Paragraph 5.133 explains that Georgian, Victorian and Edwardian terraces were built with a consistent pattern down the street, often a solid extension and a void for light and air. Paragraph 5.134 turns that into a rule: extensions must be subordinate and no higher than one full storey below the eaves. Full-width rear extensions higher than one storey, or half-width extensions higher than two storeys, will normally be resisted unless no harm can be shown. Putting an extension on the staircase side helps keep the rhythm.
The guide treats depth as a matter of care rather than a number, particularly beyond a single storey. Its test is the 45 degree rule: if the centre of a main window at the back of the neighbour lies within a 45 degree angle from the end of the extension, in plan and in elevation, the depth is likely to be unacceptable. For example, a ground-floor infill beside a back addition is normally acceptable; an upper-floor extension that projects beyond the existing return is normally not.
Conservation areas and permitted development
Islington has 42 conservation areas, with Article 4(2) directions made to control further development, and the design guidelines for each, such as The Angel and Highbury Fields, set their own rules. Permitted development gives 3 or 4 metres and 6 and 8 with prior approval outside conservation areas, but those rights go where a direction applies.
The guide encourages assessing the existing built form and seeking pre-application advice, and says high-quality contemporary or glazed designs can suit ground-floor extensions. Upper storeys of rear extensions should usually replicate the form and materials of the house, because they are the most visible part.
Validation and CIL
Islington’s validation requirements of 12 April 2024 say drawings are usually printable at 1:100 or 1:50, always carry a scale bar and must not say “do not scale”, with a roof plan where a roof is new or altered.
Islington CIL was set in 2014 at £300 and £250 a square metre by area, indexed since, on 100 square metres or more of new floor space, so a typical extension is outside it. Mayoral CIL is in band 1.
Rear extensions in Islington in numbers
142 of 146
Householder decisions by the London Borough of Islington between July 2025 and June 2026 (prior approvals left out) that were made inside 8 weeks.
Source: MHCLG live table PS2, district planning application statistics, July 2025 to June 2026 (GOV.UK)
One storey below eaves
Highest a rear extension should rise to remain subordinate, under paragraph 5.134.
Full width
Full-width rear extensions higher than one storey will normally be resisted.
45°
Angle from the end of the extension within which a neighbour’s main rear window makes the depth likely unacceptable.
No depth
The guide gives no depth in metres for a rear extension: the 45 degree rule and the terrace pattern decide.
Jan 2017
Date Islington adopted its Urban Design Guide SPD.
42
Conservation areas in Islington, with Article 4(2) directions made to control further development.
12 Apr 2024
Date of Islington’s current Local Validation Requirements for Planning Applications.
Source: Local Validation Requirements for Planning Applications, 12 April 2024 (London Borough of Islington)
£300 and £250
Islington residential CIL per square metre in Area A and Area B when it took effect on 1 September 2014, before indexation.
£96.97
Mayoral CIL per square metre for permissions granted in 2026 in Islington, which is in band 1 (£80 when set in 2019). It applies only where CIL is due at all.
Source: Mayoral CIL: Annual CIL Rate Summary 2026 (London.gov.uk)
Questions about rear extensions in Islington
How deep can I go in Islington?
The guide gives no figure. The 45 degree rule from the neighbour’s rear window decides, with care about the terrace’s pattern. Permitted development gives 3 or 4 metres outside conservation areas.
Can I extend upwards at the back?
Extensions should be no higher than one storey below the eaves, and upper extensions that project beyond the existing return normally disrupt the terrace.
Is a ground-floor infill acceptable?
Ground-floor infill extensions are normally acceptable in design terms, as the guide’s Figure 19 shows, if the neighbours’ amenity is respected.
Do I pay CIL on a kitchen extension?
Not normally. CIL arises from 100 square metres of new floor space or a new dwelling.
See how far your Islington house can go
Send the address and a photo of the back. We reply with the route and a fixed fee, from £475 drawings + £150 survey (£625 total).