Roof alteration in Hillingdon: Planning Permission Guide
What you need to know about roof alterations in Hillingdon — re-roofing, rooflights, and changing materials.
Check if your roof alteration qualifiesRoof alterations in Hillingdon at a glance
approved *
application fee
weeks typical
Based on 12 decided applications in Hillingdon over 12 months (8 granted, 4 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.
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Approval probability, 5 nearest comparables, refusal reasons — for your specific address.
Recent roof alteration decisions in Hillingdon
The 5 most recent decided applications. Addresses redacted to postcode area.
Conversion of roof space to habitable use including 2no. front facing roof lights and 2no. rear facing roof lights.
Variation of Condition 2 (approved plans) of planning permission ref. 44049/APP/2025/799, dated 09-09-25 (Demolition of existing two-stor…
Retention of roof lights, in breach of Condition 2 (ref.13746/APP/2014/845 date 12/05/14, appeal ref. APP/R5510/D/14/2220009). Applicatio…
Erection of two storey rear, side and front extension, 3 x roof lights, amendments to fenestration, following demolition of existing side…
Installation of roof lights to rear roof slope and erection of outbuilding to rear garden (Application for Listed Building Consent)
These are borough-wide. See the 5 nearest to your address.
Get my report — £9Permitted Development Rules
Any other alteration to the roof of a dwellinghouse
GPDO 2015, Schedule 2, Part 1, Class C
Roof alterations (other than dormers and loft conversions) are covered by Part 1, Class C of the GPDO. The key rule is that the alteration must not project beyond the existing roof plane.
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.
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Check my limitsTypical Costs in London
Roof alteration costs vary depending on the scope — adding rooflights is much cheaper than a full roof replacement.
Cost per m²
construction rate
Typical total
Typically includes
Typically excludes
Covers re-roofing, changing roof materials, adding rooflights. Full roof replacement is at the higher end.
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Get my estimateWhich Professionals Do You Need?
Most roof alterations don't need an architect, but a roofing contractor or draughtsperson can prepare any required drawings.
A draughtsperson or architectural technician can prepare any drawings needed. A full architect may not be necessary.
Roof alterations may need drawings for Building Regulations, but a draughtsperson or roofing contractor can often provide these.
Typical fee: £500–£2,000 (Basic drawings if needed)
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.
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Get personalised guidanceConservation Areas & Listed Buildings
In conservation areas, roof alterations that change the appearance of the roof may be more tightly controlled. Materials should match the existing roof.
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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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.
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