Single-storey side extensions in Hillingdon
Hillingdon approved 213 of the 251 planning applications for single-storey side extensions it decided in the last five years (85%), and the typical decision took 56 days.
London Borough of Hillingdon · planning applications received Oct 2021 to Oct 2026 · updated 25 Oct 2026
Approved
213 of 251
85% of decided applications; 3 withdrawn, 14 undecided
Typical time to a decision
56 days
median, from 251 decisions with both dates published
Decided within 8 weeks
129 of 251
8 weeks is the usual statutory period; councils can agree extensions
See what was approved near your own address
The The Signal Report shows approvals and refusals for single-storey side extensions within 250 m, 500 m and 1 km of your home, the council's reasons for refusing similar schemes, your property's planning history and the constraints on the plot. Free preview for any address.
Recent decisions
- ApprovedRuislip
Erection of single storey side extension.
51737/APP/2026/2030 · decided 20 Oct 2026
- ApprovedUxbridge
Erection of a single storey side extension and rear extension, following the demolition of existing rear extension.
52838/APP/2026/2033 · decided 15 Oct 2026
Erection of single storey front infill and side extension
22901/APP/2026/2013 · decided 9 Oct 2026
- RefusedYiewsley, UB7 8JZ
Two storey rear extension and single storey side extension
79003/APP/2026/1901 · decided 9 Oct 2026
- RefusedHayes
Erection of a part single storey, part two storey extension to the front and side, erection of a single storey extension to the rear
54287/APP/2026/1660 · decided 24 Aug 2026
Why Hillingdon refuses single-storey side extensions
The council's own words, quoted from recent decision notices.
“1. The development by virtue of its depth, width, overall size, bulk and proximity to neighbouring property at 59 Whitethorn Avenue would be detrimental to the residential amenities of the occupiers by reason of loss of light, loss of outlook, overshadowing and overdominance. The proposal would therefore be contrary to Policy BE1 of the Hillingdon Local Plan: Part One - Strategic Policies (2012), Policies DMHB 11 and DMHD 1 of the Hillingdon Local Plan: Part 2 - Development Management Policies (2020) and the National Planning Policy Framework (2026). 2. The proposed extension, by virtue of it…”
“1. he proposed development, by reason of its overall scale, width, positioning, cumulative bulk and massing of the proposed 2-storey side extension, when combined with the existing hip to gable roof extension and large rear dormer, would result in an incongruous, visually awkward and over- dominant form of development that would fail to appear subordinate to the original dwellinghouse. The proposed two storey side extension would fail to respect the architectural composition of the host dwelling and would unbalance the appearance of the semi-detached pair. By virtue of the site's prominent co…”
“1. The proposed development, by reason of the excessive scale, bulk, width and design of the side and roof extensions, would fail to appear subordinate to the host dwelling and would result in an overly wide, bulky and visually dominant form of development. The proposal would erode the sense of openness between properties and fail to integrate with the character of the surrounding area, causing harm to the character and appearance of the original dwelling and the wider street scene. The proposal is therefore contrary to Policies DMHB 11, DMHB 12 and DMHD 1 of the Hillingdon Local Plan Part 2…”
Other home extensions in Hillingdon
- Loft conversions
786 of 931 approved (84%)
- Single-storey rear extensions
1,395 of 1,564 approved (89%)
- Two-storey and first-floor extensions
618 of 817 approved (76%)
How these figures are made
Planning applications London Borough of Hillingdon received Oct 2021 to Oct 2026, from the council's public planning register as collected by Planning Signal. An application counts as a single-storey side extension when its own description says so (rules-based classification, tested against blind labelled samples). Duplicate records of one application are counted once. The approval figure counts approved and refused planning applications only: withdrawn and undecided ones, lawful development certificates and prior approvals are left out. Decision times use the received (or validated) date and the decision date the council published.
Past decisions describe what happened to other applications. They are not a prediction for yours: every application is decided on its own design and the council's current policies.