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Architectural drawings on a desk with a coffee cup, book, and rolled plans in warm morning light — representing professional planning guidance for Northern Ireland homeowners

Planning Permission NI

Clear guidance for Northern Ireland homeowners

Do I Need Planning Permission in Northern Ireland?

Most homeowners aren’t sure whether their project needs planning permission and the rules in Northern Ireland differ from the rest of the UK. GT Building Design prepares all drawings and manages every Planning Permission application on your behalf, ensuring your project starts correctly and complies fully.

What Planning Permission Covers

Planning Permission decides what you can build, where you can build it, and how it looks.

 

It deals with:

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  • Neighbours and privacy

  • Streetscape and visual appearance

  • Light and overshadowing

  • Local planning policies

  • Conservation areas, Areas of Townscape Character (ATCs), and coastal zones — where design controls are stricter to preserve local character and setting

 

Under NI planning law, any work that changes the structure of your home is considered development, meaning it may require Planning Permission or a Certificate of Lawfulness.

 

Planning Permission is separate from Building Control — many projects require both.

Planning Permission vs Building Control (NI)
The Simple Explanation

Homeowners often mix these up, so here’s the clear version:

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  • Planning Permission decides what you’re allowed to build.

  • Building Control checks how it’s built.

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Planning deals with appearance, size, neighbours, streetscape, conservation areas. Building Control deals with structure, safety, insulation, drainage, fire protection.

 

Most projects need Building Control, even if they don’t need Planning Permission.

Extensions - Planning Permission Rules in NI

When Planning Permission Is Required

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Planning Permission is normally required for:

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  • Extensions beyond permitted development limits

  • Two‑storey extensions

  • Front extensions

  • Extensions visible from the road in conservation areas

  • Significant roof shape changes

  • Extensions that alter the principal elevation

  • Extensions that overshadow neighbours or reduce privacy

 

Permitted Development - NI Limits

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Some extensions may fall under Permitted Development if they meet all of the following NI rules:

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  • Extension + other outbuildings must cover less than half the garden

  • Extension must not be higher than the existing house

  • Projection limits: 4m for detached homes / 3m for semi‑detached or terraced homes

  • Eaves within 2m of a boundary must be max 3m high

  • No part may extend beyond a principal elevation facing a road

  • Materials must be similar in appearance

  • Conservation areas have stricter rules

 

Even if your idea appears to fit these limits, the only way to get certainty is to submit either:

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1. Full Planning Application, or

2. Certificate of Lawfulness

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Why Full Planning Permission is the safer route

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Permitted Development can be restrictive, and Certificates are only approved when every rule is met exactly.

 

A Full Planning Application is often the safer and more reliable option because:

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  • You receive formal approval that remains valid if you ever sell your home

  • Estate agents and solicitors routinely check for planning compliance

  • Buyers gain confidence knowing the work was properly approved

  • Councils are less likely to challenge or question the work in future

 

I’ll advise clearly on which route applies to your project — and when Full Planning Permission is the better long‑term choice.​​

Loft Conversions - Planning Permission Rules in NI

Internal Loft Conversions

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Internal loft conversions with skylights do not require planning permission.

 

Dormers and Roof Alterations

 

Planning Permission is required if:

  • A dormer faces the road

  • You’re in a conservation area

  • Rooflights project more than 15cm on a road‑facing slope

  • Dormers are higher than the existing roof

  • Dormers are not 0.5m from ridge, eaves or party walls

  • Materials do not match the existing house

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These rules are often misunderstood — I’ll confirm exactly what applies to your home.

Garage Conversions - Planning Permission Rules in NI

When Planning Permission Is Not Required

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Planning Permission is not required if:

  • You’re converting the garage internally

  • You’re not altering the external appearance

  • You’re not adding windows facing a road

  • You’re not extending the footprint

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When Planning Permission Is Required

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Planning Permission is required if:

  • You’re changing the external appearance

  • You’re adding new openings facing a road

  • You’re extending the garage

  • You’re in a conservation area

What I Prepare for Your Planning Application

I manage the entire submission process from start to finish, including:

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  • Existing and proposed drawings

  • Plans and elevations

  • Block plans

  • Site Location Plan

  • Design statement (if required)

  • All communication with the Planning Department

  • Amendments requested by the Planning Case Officer

 

You don’t deal with Planning — I handle it all for you.

Typical Approval Timelines

  • 8 -12weeks — standard applications

  • 12 + weeks — complex sites

  • Longer if Planning requests amendments

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I manage the process and keep you informed throughout.

Common Issues Homeowners Face

These are the problems I resolve regularly:

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  • Builders starting work without planning

  • Incorrect assumptions about permitted development

  • Poor‑quality drawings rejected by Planning

  • Overlooking and privacy concerns

  • Roof alterations not matching policy

  • Neighbour objections

  • Delays due to missing information

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A clear, well‑prepared application avoids most of these.

Why Planning Permission Matters

Getting planning wrong can lead to:

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  • Enforcement notices

  • Forced removal of work

  • Delays and extra costs

  • Problems when selling your home

  • Mortgage or insurance complications

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A proper application protects your project and your property value.

How I Help

I specialise in:

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Accurate, compliant drawings

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✅  Straightforward communication

✅  Managing the entire application

✅  Ensuring compliance with NI planning policy

✅  Guiding you through every step

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My role is to make the process simple and predictable.

Considering a Project? Start with a Feasibility Study

If you’re unsure whether your idea needs planning permission — or whether it’s even possible — a feasibility study is the best first step. It answers:

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  • What’s allowed

  • What’s not

  • What Planning will likely approve

  • What Building Control will require

  • What the project will involve

  • Whether the idea is worth pursuing

 

This prevents wasted time, unnecessary drawings, and unrealistic expectations.

Why Homeowners Choose GT Building Design

With over 40 years’ experience helping homeowners across Northern Ireland, GT Building Design specialises in thoughtful, compliant and cost‑aware design.

 

As a Chartered Architectural Technologist, Glenn Thompson MCIAT focuses exclusively on residential design, Planning Permission and Building Control approvals — ensuring your project is technically correct, fully compliant, and ready to build.

 

Whether you’re planning an extension, loft conversion, garage conversion, or internal alterations, you’ll receive clear guidance and professional drawings tailored to your home and local regulations.

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Every project begins with a clear conversation — let’s make your plans compliant, practical, and ready to build.

Frequently Asked Questions - Planning Permission NI

Do I need Planning Permission for a house extension in Northern Ireland?

Not always. Some extensions may fall within Permitted Development rights, while others require a formal Planning Application. Factors such as size, location, design and site constraints can affect whether Planning Permission is required.

 

How long does Planning Permission take in Northern Ireland?

Most householder Planning Applications are determined by the local council within several weeks, although timescales can vary depending on workload, consultations and the complexity of the proposal.

 

Can you tell me if my project is likely to receive Planning Approval?

Yes. Before preparing a Planning Application, we can assess the proposal and identify potential planning issues, helping you make an informed decision before investing further time and money.

 

Do I need Planning Permission for a garage conversion?

Many internal garage conversions do not require Planning Permission, provided the external appearance of the property is not significantly altered. However, Building Control approval is often still required.

 

Do I need Planning Permission for a loft conversion?

Some loft conversions may be possible without Planning Permission, while others require approval due to roof alterations, dormer windows or the specific characteristics of the property.

 

What drawings are required for a Planning Application?

A Planning Application typically requires existing and proposed drawings, a site location map, block plans and supporting information relevant to the development. The exact requirements vary depending on the project.

 

What happens after Planning Permission is granted?

Planning Approval is often only one stage of the process. Most building projects will also require Building Control approval before construction can commence, ensuring compliance with Building Regulations.

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