96,527 real decisions from 311 UK councils. See what actually gets approved, what gets refused, and why — so you don’t waste thousands on drawings for something your council will reject.
Last updated: August 2026
80.2%
approval rate across 96,527 decisions
That means roughly 1 in 5 two-storey extension applications are refused — often due to avoidable design issues.
96,527
Decisions
77,375
Approved
19,152
Refused
311
Councils
Two-storey extensions face more scrutiny than single-storey ones — they are taller, more visible, and have greater impact on neighbouring properties. Approval rates are slightly lower as a result.
What these results show
• Two-storey extensions are never permitted development — they always require a planning application.
• The most common refusal reason is overbearing impact on neighbours, particularly rear-facing windows and gardens.
• Setting the first floor back from the boundary (typically 1–2m) significantly improves approval chances.
• Councils in urban areas tend to be stricter on two-storey than rural councils — local precedent is key.
Real examples showing what works — and what gets refused. Use the filters to compare approved and refused applications.
Seeing similar two-storey extensions refused? Your property might be in a stricter area — or these patterns might not apply locally. See your local approval pattern →
22/01051/NMA
Approved
Non material amendment sought to approved two storey side extension under planning permission ref 21/01590/FUL for 2 additional windows and changing pitched roof to flat roof
Listed building consent for a change of use from offices to 8 dwellings; demolition of outbuilding to rear of no.9 to be replaced with 2 storey extension; demolition of single storey flat roof extension to rear of no.6
Listed building consent for the installation of a glass roof over the lower ground floor rear lightwell; damp-proofing works and installation of insulation at lower ground floor level; construction of a first-floor extension over the existing rear outrigger; internal alterations to the lower ground,
▸ Listed building applications succeed when design is sensitive to the original character.
09/199/LB
Refused
Expose stone gable and frontage with lime mortar repairs; wet harl outbuildings and extensions; re-roof with slate and stone; internal alterations including new toilets; convert outhouse to kitchen/dining area; add scullery and two storey rear extension; and demolish part of outbuilding to form cour
Lawful Development Certificate for the Proposed Erection of a Single Storey Side Extension, Two Storey Rear Extension, Porch and a Detached Outbuilding Along With Revised Driveway to the Existing Dwellinghouse
Non material amendment to planning permission 25/00052/FUL for the demolition of existing conservatory, shed and porch, erection of two storey side extension, single storey rear extension, front porch and part garage conversion. [For clarification this is an amendment to the designs of the parapet d
Erection of pitched roof over existing flat-roof extension to rear, 1 no. new dormer window, 2 storey extension to existing single storey off-shot, external stair and railing to rear ground floor, alterations to front and rear boundary treatments,...
Demolition of the existing single storey rear extensions and the construction of two storey rear extensions including front and rear dormer windows and increasing the roof height of the main building to create 3 flats.
▸ Single-storey extensions face less scrutiny than two-storey.
2021/1599
Approved
Upward extension to convert existing bungalow into two storey dwellinghouse with two storey rear extension and changes to external facing materials and fenestration details (Application for prior approval of a proposed enlargement of a dwellinghouse by constructing additional storeys)
Demolition of existing garage, outbuildings and existing porch structure. Erection of new porch structure, one and two storey rear extension and single storey side extension. Aesthetic changes to all elevations and amendments to existing roof structure. (Revised scheme, already commenced)
Non-material Amendment of 24/00751/FUL: Changing the external first floor finish of the proposed two-storey extension at the side and front elevations from facing brick / render to composite cladding
Erect single storey front extension, erect balcony to first floor front, erect first floor rear extension, form hipped to gable roof with dormers to front and rear elevations with Juliet balcony to rear
Consultation from Mole Valley District Council for the Erection of two storey rear extension with balcony and insertion of 1 No. dormer window and 1 No. roof light to front elevation.
Non material amendment - Construction of two storey extension and glazed timber lean-to to rear (east) elevation (amendment to application FUL/2008/1094 granting approval for change of use of former industrial unit to dwellinghouse)
Article 16 consultation from Manchester City Council in relation of application 128908/FO/2020 for Erection of a two storey side extension to form additional living accommodation and formation of driveway at front of property.
Partial Demolition of 2 Storey Extension to Rear with Partial Infill and Remedials of Resultant Exposed Facades. In Addition, Demolition Works Associated with Remedial Measures to Resultant Gable of 156 High Street Due to Demolition of Adjacent Shopping Centre.
Discharge of condtion 6 (security shutters) of planning consent 14/P/00258 for Erection of a single storey extension to existing garage, erection of two-storey extension to existing dwelling, widening of existing asphalt driveway and alterations to ground levels & new treatment to boundary adjacent
Application to vary conditions 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 26, 27, 29 and 32 of the approved planning permission 20/P/1673/FUL (reconfiguration and two storey extension to the existing retail unit to include a gym (use class E) and additional ground floor reta
▸ Two-storey approvals often involve setbacks from boundaries and matching materials.
22/00529/FUL
Approved
Demolition of existing extension and outbuildings. Construction of replacement, part one and part two storey extension, and a roof terrace above the single storey component to provide ancillary accommodation. Associated works to the elevation of the house. Landscape works, including replacement of e
▸ Two-storey extensions face higher scrutiny due to greater neighbour impact.
23/00363/FUL
Refused
Full Planning Application for the construction of a two storey extension to the single-family dwelling bungalow; to create 2 self-contained flats, with associated bicycle parking and refuse storage.
Request for comments by Bristol City Council on an application that crosses the boundary into an adjoining authority: - Demolition of garage. Erection of two storey rear extension to facilitate subdivision of 1no. dwelling into 3no. dwellings with associated works.
Demolition of an existing garage, construction of a replacement garage, a first-floor extension, a replacement entrance porch and associated site improvements
▸ Replacing an existing structure is generally viewed more favourably than building new.
181442/DPP
Approved
Change of use from class 7 (hotels and hostels) to form 10 no. residential flats (sui generis) including alteration to existing rear extension and erection of 2 storey extension to rear; installation of replacement windows to front; dormers replacement to rear and formation of new entrance at lower
Full planning application for single and two storey rear extension and retrospective chicken coop and canopy to agricultural building, use of land for garden and parking area and track
Craven · Skipton West & West Craven · Fri 03 Oct 2025
▸ Two-storey extensions face higher scrutiny due to greater neighbour impact.
Retrospective amendment to planning consent TP/ED/20/0191 - two storey side extension, single storey rear extension, front porch and addition of rear dormer window
Proposed single storey rear extension (including part demolition of existing single storey rear extensions) first floor rear extension and Juliet balcony to existing rear elevation.
Erection of two storey extension to rear with installation of mezzanine floor, new shop front and associated plant and machinery. Reconfiguration of car parking to rear and front to include public realm, landscaping and associated infrastructure works