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Planning
Is Planning Permission Necessary? How to Make a Planning Application Once your Planning Application is Received Decision Outcomes Appealing a Decision What Happens NextBuilding Regulations
Prepare to Build Building Control Conservation Areas Tree Preservation Orders (TPOs) Listed Buildings The Party Wall etc. Act 1996 Basement Development Advice HETAS NICEIC Gas Safe Construction Management Waste Management Interior DecorationMost loft conversions in England can proceed as permitted development without a planning application, but volume limits, roof type, location and property type all affect whether that right applies to you. Read on to find out exactly where you stand before work begins.
5 min read
Source: GPDO 2015 — Class B volume limits and Article 2(3) exclusions
Source: GPDO 2015 — Class B volume limits and Article 2(3) exclusions
Source: GPDO 2015 — Class B roof enlargement conditions (height and dormers)
Source: GPDO 2015 — Class B roof enlargement conditions (height and dormers)
Source: GPDO 2015 — Class B volume limits and Article 2(3) exclusions
Source: GPDO 2015 — Class B volume limits and Article 2(3) exclusions
Source: GPDO 2015 Householder Technical Guidance — MHCLG, Planning Portal — Loft conversion permitted development guidance
Before starting any loft conversion it is wise to ask your council's planning service whether the specific proposal falls within PD rights. Regulations are continually updated, and local circumstances — such as an Article 4 direction — can restrict rights that would otherwise apply.
| House type | Maximum additional roof space (cubic metres) | Previous enlargements count? |
|---|---|---|
| Terraced house | 40 cubic metres | Yes — any earlier roof enlargement must be included in the allowance |
| Semi-detached or detached house | 50 cubic metres | Yes — any earlier roof enlargement must be included in the allowance |
The volume is measured against the 'original roof space' — that is, the roof space as it existed in the original building (or as it stood on 1 July 1948 if built before that date). If a previous owner has already extended the roof, that volume counts towards your allowance even if you did not carry out the work yourself.
In addition, no part of the enlarged house may exceed the height of the highest part of the roof of the existing house. The highest part is the ridge line of the main roof (or the highest roof where roofs are flat). Chimneys, parapet walls and similar protrusions above the ridge line are not taken into account when making this assessment.
The position of your proposed alteration relative to the street matters a great deal. Dormer windows and any other enlargement that would extend beyond the plane of an existing roof slope on the principal elevation of the house — where that elevation fronts a highway — are not permitted development and will require a planning application.
Rooflights on a principal elevation are treated differently: they may be permitted development under Class C of Part 1, Schedule 2, provided they meet the requirements of that Class, because they do not project beyond the plane of the existing roof slope.
Materials used in any exterior work must be of a similar appearance to those used in the construction of the exterior of the existing house. This condition applies to all roof alterations that are permitted development under these rules.
Householder permitted development rights for roof extensions are removed entirely in certain locations and for certain property types. On Article 2(3) land — which includes National Parks, the Broads, areas of outstanding natural beauty (legally still an Area of Outstanding Natural Beauty / AONB), conservation areas, and land within World Heritage Sites — roof extensions are not permitted development and a planning application is required.
Householder permitted development rights also do not apply to flats, maisonettes, or houses created through the permitted development rights to change use set out in Classes M, N, P, PA and Q of Part 3 of Schedule 2 to the GPDO 2015. Flats and maisonettes do not benefit from normal householder permitted development rights; check with the LPA.
An Article 4 direction made by your local planning authority can also remove PD rights in a specific area or for specific types of development. Always check whether one applies to your property before assuming PD rights are available.
Even if you are confident that your loft conversion falls within permitted development, you can apply to your local planning authority for a 'lawful development certificate' (LDC). An LDC is a formal confirmation that your proposed works are lawful and do not require a planning application. It is not obligatory, but obtaining one is strongly advisable if you plan to sell the property or if there is any doubt about the position.
Permitted development rights apply to houses, not flats, maisonettes, or houses created through specified change-of-use PD rights.
Find out whether your property is in a National Park, the Broads, an AONB, a conservation area or a World Heritage Site — roof extension PD rights are removed in all of these.
Ask your local planning authority whether an Article 4 direction applies to your property, which could remove PD rights that would otherwise be available.
Include any previous roof enlargements when working out whether you are within the 40 or 50 cubic metre limit.
If a dormer is proposed on a roof slope forming the principal elevation that fronts a highway, a planning application will be required.
Consider applying for an LDC from your local planning authority to obtain formal confirmation that the works are lawful before starting on site.
Permitted development rights do not remove the requirement for building regulations approval. A loft conversion will almost always require building regulations sign-off regardless of PD status.
Permitted development rights do not remove requirements for permissions or consents under other regimes such as the building regulations and the Party Wall Act.
The limit is 40 cubic metres of additional roof space for a terraced house and 50 cubic metres for a semi-detached or detached house. Critically, any previous roof enlargement to the property — whether carried out by you or a previous owner — must be counted towards the allowance. Exceed the limit and you will need to apply for planning permission.
Source: GPDO 2015 — Class B volume limits and Article 2(3) exclusions
Yes. A dormer window or any roof enlargement that extends beyond the plane of an existing roof slope on the principal elevation of the house — where that elevation fronts a highway — is not permitted development. You will need to submit a planning application. A rooflight on the same elevation is treated differently and may be permitted development under Class C, provided it meets the relevant conditions.
Source: GPDO 2015 — Class B roof enlargement conditions (height and dormers)
No. On Article 2(3) land — which includes conservation areas, National Parks, the Broads, areas of outstanding natural beauty, and World Heritage Sites — roof extensions are not permitted development. You will need to apply for planning permission for any loft conversion in these locations, however modest the works may be.
Source: GPDO 2015 — Class B volume limits and Article 2(3) exclusions, GPDO 2015 — Schedule 1: Article 2(3) land definitions
Yes, always. Permitted development rights grant a form of planning permission but they do not remove the requirement for building regulations approval. A loft conversion involves structural alterations, fire safety, insulation and means of escape, all of which are regulated under the building regulations. Contact your local building control body before starting work.
A Lawful Development Certificate (LDC) is a formal decision by your local planning authority confirming that a proposed development is lawful and does not require a planning application. You are not obliged to obtain one, but it is strongly advisable: it provides certainty, protects you if enforcement questions arise later, and reassures solicitors and buyers if you sell your home.