Wraparound extension in Hillingdon: Planning Permission Guide
Your guide to wraparound extensions in Hillingdon — combining rear and side extensions under one project.
Check if your wraparound extension qualifiesWraparound extensions in Hillingdon at a glance
approved *
application fee
weeks typical
Based on 10 decided applications in Hillingdon over 12 months (9 granted, 1 refused). * Limited data — treat as indicative.
Hillingdon has substantial Green Belt covering its western fringes, including Harefield, Ruislip Woods, and the Colne Valley Regional Park. Conservation areas include Harefield Village, Ruislip Village, Ickenham Village, and Uxbridge. Listed buildings cluster around St Mary's Harefield and the historic village cores. Heathrow noise contours affect planning for certain projects in the south. Flood zones apply along the Colne and Frays rivers.
Want your personalised odds?
Approval probability, 5 nearest comparables, refusal reasons — for your specific address.
Recent wraparound extension decisions in Hillingdon
The 5 most recent decided applications. Addresses redacted to postcode area.
Erection of wrap-around side and rear part single part double storey extensions, front porch, conversion of roof space to habitable use t…
Erection of double storey extensions to the front, side and rear including balcony to rear, with new roof involving raising of the ridge …
Non-material amendment to planning permission ref. 79080/APP/2025/801, dated 18-07-2025 (Erection of a part single storey, part two store…
Erection of single storey wrap around extension
Variation of Conditions 2 (Approved plans), 9 (Windows and Doors) and 10 (Extensions, roof extensions and outbuildings) of planning permi…
These are borough-wide. See the 5 nearest to your address.
Get my report — £9Permitted Development Rules
Enlargement, improvement or other alteration of a dwellinghouse
GPDO 2015, Schedule 2, Part 1, Class A
A wraparound extension combines a rear and side extension. It's assessed under Part 1, Class A of the GPDO and must comply with the limits for both rear depth and side width.
Key dimension limits
These are the maximum GPDO limits for a detached house with no constraints. Your actual limits depend on your property type, location, and any planning restrictions.
Enter your postcode to see the personalised limits for your wraparound extension.
Check my limitsTypical Costs in London
Wraparound extensions cost more than a simple rear or side extension due to the larger footprint and more complex structural requirements.
Cost per m²
construction rate
Typical total
Based on 20–30 m²
Typically includes
Typically excludes
Combines rear and side extension. Costs at the higher end due to larger footprint and structural complexity.
Get a personalised cost estimate based on your actual wraparound extension dimensions.
Get my estimateWhich Professionals Do You Need?
Wraparound extensions have complex geometry with multiple roof junctions and typically benefit from professional design input.
You'll need a party wall surveyor for this project.
Wraparound extensions have complex geometry with multiple roof junctions that benefit from professional design.
Typical fee: £2,000–£5,000 (Plans + Building Regs)
Single storey extensions typically need structural calculations for any openings in existing walls and for foundations.
Typical fee: £500–£1,500
Your semi-detached house shares a boundary with neighbours. Extensions and loft work within 3 metres of a shared wall trigger the Party Wall Act.
Typical fee: £700–£1,500 (per neighbour)
This guidance is based on a typical semi-detached house with no special constraints. Listed buildings, conservation areas, and attached properties may require additional professional input.
Find out exactly which professionals you need for your wraparound extension.
Get personalised guidanceConservation Areas & Listed Buildings
In conservation areas, the side element of a wraparound extension is not permitted development. The rear element is limited to 3 metres depth.
Properties in conservation areas often have reduced permitted development rights. Some project types (like side extensions) lose PD rights entirely. An Article 4 Direction can remove additional PD rights.
Listed buildings (Grade I, II*, or II) have no permitted development rights at all. Any external alteration requires Listed Building Consent in addition to any planning permission. An architect experienced in heritage work is essential.
Check if your property is in a conservation area or has other planning constraints.
Check my propertyFrequently Asked Questions
Just want a quick yes/no for your wraparound extension?
Run our free 2-minute check to see whether your project likely qualifies as permitted development in Hillingdon. For personalised approval odds and nearby comparables, get the full report above.
Free 2-min check