Householder permitted development in Northern Ireland

Northern Ireland has its own permitted development rules, and they are not the England rules with the place name changed. If you are planning an extension in Belfast, Omagh or Ballymena, the permitted development Northern Ireland extension limits come from the Planning (General Permitted Development) Order (Northern Ireland) 2015, made under the Planning Act (Northern Ireland) 2011. Applications go to one of the 11 district councils, which took over planning functions in April 2015. Nothing in the England General Permitted Development Order applies here.

This article covers Northern Ireland only.

The Order and how it is arranged

The 2015 Order works the same way as its counterparts elsewhere in the United Kingdom. A general grant of permission sits in the body of the Order, and the Schedule then sets out classes of development, each with its own limits and conditions. Householder rights sit in the Part dealing with development within the curtilage of a dwellinghouse.

Two structural points matter before you measure anything.

First, the grant is conditional. Every class carries limits, and exceeding any one of them takes the whole proposal outside permitted development, rather than only the part that exceeds. A rear extension within the depth limit but two courses above the height limit is an extension that needs permission.

Second, the rights attach to a dwellinghouse. Flats and maisonettes do not have them, and neither does a building that has been converted without the change of use being authorised. That catches out people who bought a converted property on the assumption that its status was settled.

Extension limits and how they are expressed

The Order controls householder extensions through a set of linked limits rather than one headline figure. Read all of them against your drawings:

• The proportion of the curtilage that may be covered by buildings, measured against the original curtilage as it stood on the relevant date rather than as it is now.
• Height, expressed against the highest part of the roof of the original house and, separately, against eaves height where the extension sits close to a boundary.
• Projection beyond the rear wall of the original house, with different figures for detached houses and for other house types.
• Whether the extension would come forward of the principal elevation or a side elevation fronting a road, which is normally excluded.
• Width of side extensions relative to the original house.
• Materials, which generally have to be similar in appearance to the existing house.

"Original" means the house as first built, or as it stood on the date fixed in the Order if that is earlier than your ownership. Previous extensions count against the allowance even if someone else built them, which is why the first search on any project should be the planning history of the property on the council's online register.

Take the measurements from the current text of the Order rather than from a summary, including this one. The figures differ from those in England and Scotland, and they have been amended since 2015.

Outbuildings and the curtilage

Garden rooms, garages, sheds and greenhouses sit in their own class, with limits on height, position relative to the house and boundaries, and total ground coverage. The recurring problems are the same three every time.

Height at the boundary. A pitched roof close to a fence is the most common accidental breach.

Use. The class covers buildings incidental to the enjoyment of the dwellinghouse. A home office for occasional use is normally incidental. A room let separately, a business with customers visiting, or self-contained living accommodation is not, and the answer is an application whatever the building looks like.

Land in front of the house. Outbuildings forward of the principal elevation are typically excluded, which rules out a good proportion of the front garden schemes people ask about.

Roof alterations and dormers

Rooflights and roof alterations that do not materially alter the shape of the roof are treated more generously than dormers. A dormer changes the roof plane and the volume, so it engages the height limit measured against the highest part of the existing roof and, in many cases, falls outside the class entirely.

Where a loft conversion needs only rooflights, the questions are how far they project above the plane of the roof slope and whether the property is in a designated area. Where it needs a dormer, assume an application until the Order tells you otherwise.

Designated areas, where rights shrink

Northern Ireland has a designation set that does not match Great Britain, and it is the main reason a rule of thumb picked up elsewhere fails here.

Areas of Townscape Character deserve particular attention because they are widespread in the older suburbs of Belfast and in market towns, they are not always obvious on the ground, and many homeowners have never heard of them. Check the council's mapping before you draw anything.

The council can also make a direction withdrawing permitted development rights for a specific area, in the same way that article 4 directions work elsewhere. Directions are published documents. Ask for the reference and the boundary.

Confirming that works are lawful

A certificate of lawful use or development under the Planning Act (Northern Ireland) 2011 is the only formal way to establish that existing works are lawful, or that proposed works do not need permission. Everything else, including a council officer's view on the telephone, is an opinion.

Certificates are worth the fee in three situations: selling a property where an extension has no paperwork, starting a project where the permitted development margin is thin, and buying a property with a converted outbuilding. If the answer comes back negative, you know before you spend money, and you still have the application route. Where a council refuses a certificate or an application, the appeal goes to the Planning Appeals Commission rather than to an inspectorate, and the process is set out in our note on appeals to the Planning Appeals Commission.

Where Northern Ireland parts company with Great Britain

The headline differences for a householder:

There is no neighbour consultation scheme for larger rear extensions. England allows a bigger single storey rear extension through a prior approval procedure with a neighbour consultation stage. Northern Ireland has no equivalent, so a larger extension is a full application.

The wider change of use rights are narrower. England's routes for converting commercial premises and agricultural buildings to housing have no direct Northern Ireland counterpart, and countryside housing is governed by retained policy, which is discussed further in our note on dwellings in the countryside.

The policy backdrop differs. Development plan policy is led by the Strategic Planning Policy Statement together with retained policy documents until each council adopts its Local Development Plan. The National Planning Policy Framework has no application in Northern Ireland.

There is no Community Infrastructure Levy, and developer contributions work differently, as set out in our note on contributions without a levy.

If your works do need an application, PlanScope can draft the supporting documents, and you can browse the 66 report types to see which apply. PlanScope's drafting is grounded in English national policy, so a Northern Ireland submission needs the reviewer to check the position against the Strategic Planning Policy Statement, retained policy and your council's Local Development Plan.

This is general guidance, not legal advice, and a certificate of lawful use or development is the only formal way to confirm that works are lawful. Check the position with your district council or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.