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 Lewisham: Planning Permission Guide

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

78%

approved in Lewisham

£548

application fee

8 wks

typical decision

≤0.15m

rooflight proud

Based on 27 decided applications in Lewisham over 12 months (21 granted, 6 refused).

Lewisham has conservation areas in Blackheath, Telegraph Hill, Brockley, Lee Manor, and Forest Hill. Article 4 Directions restrict window and door alterations in several Victorian conservation areas. The borough mixes dense inner-city housing in the north with more suburban character in the south. Flood zones along the Ravensbourne and Quaggy rivers restrict outbuilding classes for riverside properties.

Council planning portal Pre-application advice

Local data PD rules Costs Professionals Constraints FAQs

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Recent roof alteration decisions in Lewisham

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

Refused

Application for a Lawful Development Certificate (proposed) submitted under Section 192 of the Town & Country Planning Act 1990 (as amend…

SE32026-09-25

Granted

Installation of solar photovoltaic panels on the flat roofs of the existing building at 10-14 Mercy Terrace, SE13, and all other associat…

SE132026-09-04

Granted

Construction of a rear loft extension and installation of two roof lights at 96 Mount Pleasant Road SE13.

SE132026-08-18

Granted

Alterations and refurbishment of the existing building in the rear garden, including a new timber roof structure and the increase of roof…

SE232026-08-13

Refused

Installation of two conservation style roof lights in the front and rear roof slopes at Flat 5, 40 Bromley Road SE6.

SE62026-08-12

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.

Check if your property is in a conservation area or has other planning constraints.

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Frequently Asked Questions

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Related guides

Loft conversion

GPDO Class B

Dormer

GPDO Class B

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