Do I need planning permission to change my roof tiles?

Not usually, as long as the new materials don't project beyond the existing roof plane. In conservation areas, you should match the existing materials.

Can I add rooflights without planning permission?

Generally yes, under Class C, as long as they don't project more than 150mm beyond the roof plane.

How much does a roof alteration cost?

Roof alteration costs in London typically range between £5,000 and £15,000, with rooflights at the cheaper end and a full re-roof with new materials at the higher end.

Do I need Building Regulations for a roof alteration?

Depending on the work, you may need Building Regulations approval for structural changes, insulation, or fire safety requirements.

Project guideGPDO Class C

Roof alteration in Merton: Planning Permission Guide

What you need to know about roof alterations in Merton — re-roofing, rooflights, and changing materials.

83%

approved in Merton

£548

application fee

8 wks

typical decision

≤0.15m

rooflight proud

Based on 41 decided applications in Merton over 24 months (34 granted, 7 refused).

Merton has conservation areas including Wimbledon Village, Wimbledon Common, Mitcham Cricket Green, and Cannizaro Park. Listed buildings cluster around Wimbledon Common and Merton Abbey Mills. Wimbledon Common is Metropolitan Common Land with its own byelaws near the edges. Article 4 Directions cover parts of Wimbledon Village. The borough has a mix of affluent Edwardian housing around Wimbledon and Victorian terrace stock in Mitcham and Colliers Wood.

Council planning portal Pre-application advice

Local data PD rules Costs Professionals Constraints FAQs

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Recent roof alteration decisions in Merton

The 5 most recent decided applications. Addresses redacted to postcode area.

Granted

FIRST FLOOR EXTENSION, GARAGE CONVERSION TO HABITABLE SPACE, INCLUDING SOLAR PANELS, AND AIR SOURCE HEAT PUMP. 

SW192026-07-20

Granted

FULL PLANNING APPLICATION FOR ROOF ALTERATIONS INCLUDING THE PROVISION OF 4 NO. NEW MECHANICAL VENTILATION INTAKE AND DISCHARGE COWLS I…

SW192026-07-02

Refused

APPLICATION FOR THE ERECTION OF THE ROOF ALTERATIONS AND EXTENSIONS FOR THE ADDITIONS OF 2 X SELF-CONTAINED FLATS AT ROOF LEVEL.

2026-06-24

Granted

Erection of a single-story rear infill extension, including the installation of two roof lights and the installation of a window and Fren…

SW192026-06-08

Granted

Re-configuration of ground floor layout with re-configuration and extension to first floor. Alterations to loft roof space to provide add…

SW192026-05-26

These are borough-wide. See the 5 nearest to your address.

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Permitted Development Rules

Class CPart 1

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

Must not project beyond existing roof planeMaterials must match existing

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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Typical Costs in London

Roof alteration costs vary depending on the scope — adding rooflights is much cheaper than a full roof replacement.

Roof alterationLondon

Cost per m²

£800–£2,000

construction rate

Typical total

£5,000–£15,000

Typically includes

MaterialsLabourScaffolding

Typically excludes

Planning application feeBuilding regs fee

Covers re-roofing, changing roof materials, adding rooflights. Full roof replacement is at the higher end.

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Which 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.

Architect / designerOptional

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)

Structural engineerNot needed

Party wall surveyorNot needed

Planning consultantNot 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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Conservation 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.

Conservation areas

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

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.

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Frequently Asked Questions

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Loft conversion

GPDO Class B

Dormer

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