Kingston rooflight appeal confirms Class C rights

The Kingston rooflight appeal has overturned a council refusal to recognise permitted development rights for a new side-facing roof window at a house in Kingston upon Thames. The Inspector found that doubts about earlier roof alterations had not been substantiated.

The certificate appeal concerned 18 Burton Road and was decided on 7th October 2026. It is especially relevant to anyone preparing a lawful development certificate for a rooflight under Part 1 Class C of the GPDO.

The outcome was not a blanket ruling that previous alterations can be ignored. Instead, the Inspector examined the evidence available, the limits of Class C and whether the council had established a reason to refuse this specific proposal.

Kingston rooflight appeal: what the owner proposed

The application concerned a single side rooflight serving a second-floor washroom at 18 Burton Road. The owner applied under section 192 of the Town and Country Planning Act 1990 for a certificate confirming the lawfulness of the proposed operation.

Kingston Council refused application 24/03225/CPU in April 2025. The authority considered the information provided about an existing ‘piggyback’ roof extension, which had been built following an earlier permission, inconsistent or imprecise.

The dispute was therefore not about a scheme for a large dormer or a new habitable room. It concerned whether one roof window could be installed under existing permitted development rights.

Inspector A U Ghafoor determined appeal APP/Z5630/X/25/3369045 on 7th October 2026. The appeal was allowed and a certificate issued for the single rooflight shown on the submitted drawings.

Why earlier roof works did not defeat the certificate

The house had an existing roof extension, and its ridge had been raised. The roof alteration was set back from the front elevation. Those facts alone did not tell the Inspector that the development was unauthorised.

The Kingston rooflight appeal decision says the council failed to identify clearly the alleged discrepancies in the earlier works. There was no evidence before the Inspector demonstrating that the existing extension itself lacked authorisation.

The property remained occupied as a dwellinghouse. The Inspector also found no evidence that the house had lost the relevant permitted development rights through a condition or other applicable restriction.

This matters because a decision on a proposed lawful development certificate must be based on a proper analysis of the operation proposed and the legal position at the application date. A suspicion about previous works may justify investigation, but unsupported suspicion is not a substitute for demonstrating a restriction.

The Inspector concluded that the applicant had discharged the burden of proof on the balance of probabilities. The certificate was therefore issued under the statutory appeal powers in section 195.

How Part 1 Class C applies to side rooflights

Part 1 Class C of Schedule 2 to the Town and Country Planning (General Permitted Development) (England) Order 2015 covers certain alterations to the roof of a dwellinghouse, including rooflights which do not amount to an enlargement under Class B.

Class C has physical limits. In particular, an alteration must not project more than 0.15 metres beyond the plane of the original roof slope, measured perpendicularly, or make the highest part of the alteration higher than the highest part of the original roof.

An upper limit applying to a proposal’s height and projection is not the whole test. Class C is subject to additional exclusions and conditions, and the status of the building as a dwellinghouse and the availability of permitted development rights must also be established.

For a roof window on a roof slope forming a side elevation, condition C.2 requires obscure glazing. Any openable part must be more than 1.7 metres above the floor of the room, unless the window is non-opening.

The Kingston rooflight appeal drawings showed an openable roof window with obscure glazing. The Inspector found nothing in the evidence demonstrating that the proposal conflicted with the restrictions in C.1 or the conditions in C.2.

These requirements are explained in the government’s householder permitted development technical guidance and Planning Geek’s Class C rooflight guide.

What the certificate actually confirms

The successful appeal resulted in a certificate for the installation of one side rooflight in accordance with the listed proposed plans, rather than permission for a redesigned roof, another roof extension or additional windows.

The certificate records the lawfulness of the proposed development as at 6th January 2025, the relevant application date. It identifies the property and the precise drawings on which the Inspector relied.

The description of the window and its position matters. If the installed window varies materially from the certified operation, the certificate may not answer whether those different works are lawful.

Likewise, a certificate does not retrospectively legalise every earlier alteration to a house. It determines the question actually asked. Practitioners should avoid implying that one successful Class C certificate resolves the lawful status of the entire roof.

The evidence that makes a Class C application robust

Start with an accurate site plan and photographs demonstrating that the building is a dwellinghouse with the relevant rights. Where a previous permission altered the roof, include the approved drawings, decision notice and evidence of what was actually constructed.

Provide elevations and roof plans at consistent scale. Label the original roof slope, rooflight projection and ridge relationship so that the Class C measurement can be tested instead of assumed.

For a side-facing window, show its glazing treatment and operation. Drawings should establish the room’s floor level and height of any opening parts, rather than merely indicating that privacy glass will be fitted.

Check every route by which permitted development may have been restricted. An Article 4 direction, a permission condition or a particular planning history can change the analysis even where the physical proposal appears straightforward.

Where the council alleges an earlier irregularity, ask what particular deviation from approved plans it says has occurred. A focused evidence response can expose whether the concern relates to the new window, the original permission or a different enforcement question.

Planning Geek also explains how to check Article 4 directions, and when a lawful development certificate appeal is appropriate.

Read the original decision

The primary source is Planning Inspectorate appeal APP/Z5630/X/25/3369045, decided on 7th October 2026. The decision text is also available through the Appealbase decision record.

This is an individual Inspector’s decision, not a binding court judgment. The Kingston rooflight appeal is valuable for its application of Class C and the burden of proof to a particular property, not as a universal exemption from examining previous works.