Roof alteration in Westminster: Planning Permission Guide
What you need to know about roof alterations in Westminster — re-roofing, rooflights, and changing materials.
Based on 30 decided applications in Westminster over 12 months (27 granted, 3 refused).
The City of Westminster has the densest concentration of conservation areas and listed buildings in the UK, covering almost the entire borough. Article 4 Directions layer on top of this in many areas, restricting virtually any external alteration. Listed building consent is required frequently in addition to planning permission. The council's design expectations are among the most stringent in the country — professional planning advice is essential.
Recent roof alteration decisions in Westminster
The 5 most recent decided applications. Addresses redacted to postcode area.
Replacement roof lantern and roof tiles. (Linked with 26/04387/FULL)
Replacement roof lantern and roof tiles. (Linked with 26/04388/LBC)
Detailed written and photographic specification of the facing materials you propose to use, including glazing, along with annotated versi…
Details of written photographic specification of the materials; exterior of the new extension; new windows, rooflights, and doors; new ro…
Detailed roof layout demonstrating that the installation of photovoltaic (PV) panels has been maximised pursuant to Condition 29 of plann…
These are borough-wide. See the 5 nearest to your address.
Check your address freePermitted 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.
Enter your postcode to see the personalised limits for your roof alteration.
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.
Get a personalised cost estimate based on your actual roof alteration dimensions.
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.
Find out exactly which professionals you need for your roof alteration.
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
Just want a quick yes/no for your roof alteration?
Run our free 2-minute check to see whether your project likely qualifies as permitted development in Westminster — your address, your constraints, your council's own recent decisions.
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