Wraparound extension in Hounslow: Planning Permission Guide
Your guide to wraparound extensions in Hounslow — combining rear and side extensions under one project.
Based on 37 decided applications in Hounslow over 24 months (28 granted, 9 refused).
Hounslow has conservation areas around Chiswick (including the Bedford Park fringe shared with Ealing), Brentford, Isleworth, and Syon. Listed buildings are concentrated around Syon House, Osterley Park, Chiswick House, and Boston Manor. Article 4 Directions cover parts of Chiswick and Brentford. Flood zones apply along the Thames, particularly around Brentford and Isleworth. Heathrow noise contours affect some planning considerations in the west.
Personalised odds
5 nearest comparables & refusal reasons for your address.
Get my report — £9See a sample →Recent wraparound extension decisions in Hounslow
The 5 most recent decided applications. Addresses redacted to postcode area.
Erection of a side infill extension. Conversion of the existing garage to a habitable space. Replacing all the existing windows. Installa…
Rear and side roof extensions to number 2 and 4 Vaughan Avenue W6 0XS.
Grand floor side and wraparound extension
Single storey wrap around extension
Alterations to the existing single-story wrap-around extension to improve thermal efficiency and the replacement of all existing windows …
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
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