Planning permission for skylights and rooflights in England

Planning permission is not needed for every change to a house, because the law grants a set of automatic permissions called permitted development rights. For the roof of a house, the relevant one is Class C of Part 1 in the General Permitted Development Order, headed other alterations to the roof. Government guidance says Class C covers the installation of roof lights and windows, so a straightforward new skylight or rooflight is exactly what it was written for.

The right comes with limits and one condition. Pass them all and the work is lawful without an application. Fail one and the job needs the council's consent first. The table sets out the limits; the sections below take each in turn.

Permitted development also does not switch off other regimes. A new opening can still need Building Regulations approval, which is a separate question covered in our guide to skylight building regulations.

The projection limit is 150 mm, and the frame counts towards it. It is measured beyond the plane of the original roof slope, at right angles to the roof surface. A roof window set in plane with the tiles or slates can sit well inside that figure. A raised rooflight on a kerb is where the number starts to matter.

The height limit is separate. No part of the new work may rise above the highest part of the original roof. For this purpose the highest part is the main ridge line, and chimneys or parapets above it are ignored. A rooflight low on a slope never comes near the ridge, so the height test is rarely the one that catches a job.

Both tests refer to the original roof, not the existing one. The original roof is the one the house had on 1 July 1948; for a house built later, it is the roof as first built. If an earlier owner raised the roof or added a feature, the measurement still goes back to the original roof.

Class C carries one condition, and it catches people out. Any window on a roof slope that forms a side elevation of the house must be obscure-glazed, and it must be non-opening unless the parts that open are more than 1.7 m above the floor of the room it serves.

Read it as two separate requirements. The whole window has to be obscure-glazed, the upper and lower parts alike. The 1.7 m height decides only whether the window may open. A side-slope window can therefore be obscure and openable, but only when the opening parts sit high enough above the floor; otherwise it is obscure and fixed.

Nothing in the English rule ties this to the distance from a boundary. It applies however far the house stands from its neighbour. Where a window sits over a stair or landing, government guidance measures the 1.7 m from the point on the stair or landing directly below the centre of the window.

Government guidance also treats obscure glazing as level 3 or higher on the one to five obscuration scale, and one-way glass does not count. A house with a hipped roof has a slope facing the side, so we look at which slope a new window lands on during the survey, and we say so plainly if the rule bites.

Flats and maisonettes carry none of the householder rights that Class C belongs to. The class is written for houses, so a rooflight in a flat is a planning matter, and the freeholder will usually need to agree as well.

A house that exists as a home only because of a change-of-use permitted development right has no Class C rights either. That covers an office, shop, light-industrial or agricultural building converted under Classes G, M, MA, N, P, PA or Q of Part 3. It does not cover every conversion. A building converted with a full planning permission keeps Class C unless a condition took it away.

If you are unsure which route your house took, the planning history on the council's website can show it, and the council can confirm it.

An Article 4 direction is how a council can remove permitted development rights across part of its area. A condition on the house's original planning permission, or on a later one, can also remove them. In either case a planning application is needed, so we ask the council before work starts.

Conservation areas and landscapes

Class C has no exclusion for protected land. A conservation area, an Area of Outstanding Natural Beauty (now called a National Landscape), a National Park or a World Heritage Site leaves the right for a rooflight in place on its own. Dormers and other roof enlargements work differently, because they are not permitted development on a house in those places. That difference is why some council pages say roof alterations need permission in a conservation area, while a rooflight on its own does not.

In a conservation area or a National Landscape the council is more likely to have an Article 4 direction, which is why a check is sensible. Stockport Metropolitan Borough Council publishes the list on its website under Article 4 directions. In many of Stockport's conservation areas an Article 4 direction means changes to roofs on the parts of a house facing a road, waterway or public open space need planning permission; we check the council's list of directions for your address before any work.

Listed buildings

Class C has no listed-building exclusion, so a listed house still has the planning right. The consent that decides the job is a different one: any alteration affecting a listed building's special character needs listed building consent, whether or not planning permission is also needed. Listing covers the whole building, inside and out. Working without that consent is a criminal offence, and there is no fee to apply. You can check a house on the National Heritage List for England.

A roof lantern added to an existing flat roof usually stands well over 150 mm proud of the roof, so it normally falls outside Class C and needs planning permission unless the council confirms otherwise. We look at the height at the survey. The product is covered on the roof lanterns page, and the permission question for lanterns is the same one set out here.

On a new extension, a lantern is a different case. The extension is assessed on its own terms under Class A, so the lantern is assessed with it. We confirm the position with the council before work starts.

If there is any doubt, ask the council. For a certain answer, apply for a Lawful Development Certificate, which gives formal confirmation that no planning application is needed. For a house in the borough, the decision-maker is Stockport Metropolitan Borough Council. The government's Planning Portal roof guidance lists the same limits in a shorter form.

Some homes on the Peak District edge sit inside the national park boundary. There, planning is handled by the Peak District National Park Authority and not by the council. Its advice page on whether you need permission asks owners to make contact before changing a house in a conservation area or a listed building. The Authority does not deal with building control. That sits with the district council's team, or with a private registered approver.

You do not have to settle this alone. The survey is free, and a picture of the roof sent to WhatsApp 07880 284133 gives us a first look at which slope is involved.

Permitted development does not remove the need for Building Regulations approval or other consents. For a new rooflight, approval is generally needed for the structure, the energy performance and, near a boundary, fire.

The fitting itself is covered by a 10-year workmanship guarantee, given in writing. Where the work is notifiable, we handle the Building Regulations notification with the council's building control team or a registered building control approver. Replacing in an existing opening is lighter on paperwork than cutting a new hole, as replacing in the same opening explains.