New Planning Exemptions Ireland 2026: The Complete Homeowner Guide

Planning a house extension, garden room, attic conversion or a home for a family member in your back garden? Before ordering materials or appointing a builder, you need to establish whether the work requires planning permission.

For the wider planning process, see our Planning Permission Ireland 2026 guide. For a specific proposal, have a competent designer or the planning authority check every applicable condition.

Ireland’s residential planning exemptions changed on 27 July 2026. The changes cover several types of domestic work, including larger qualifying rear extensions, garden structures, certain dormers, house subdivisions and detached rear-garden dwellings. Each exemption comes with conditions. Official source

A project being small enough does not automatically make it exempt. Its location, use, previous development history and compliance with the remaining rules also matter. Relevant Building Regulations and fire-safety requirements continue to apply. Official source

This guide explains the main changes, the differences between common project types and what to check before you start.

Once your plans and requirements are clear, Trade Source Ireland can help you find potentially suitable tradesmen. It is free to enquire, with no obligation to proceed. Trade Source IRE

What changed under Ireland’s 2026 planning exemptions?

The following is an overview—not a substitute for checking every condition attached to your project.

These provisions are outlined in the Department of Housing’s circular accompanying the regulations. A separate regulation also introduces a conditional exemption for chimney removal. Official source

This article concerns the Republic of Ireland. Northern Ireland has a separate planning system.

What does “exempted development” actually mean?

Exempted development is development that does not require planning permission because it meets an applicable exemption.

However, the exemption only works where the proposal satisfies the relevant description, conditions and limitations. Wider restrictions can also apply under the planning regulations. Official source

For a homeowner, the practical question is therefore not simply:

“Is my extension under the size limit?”

It is:

“Does this specific extension, on this particular property, satisfy every requirement?”

Our recommendation: establish that position before paying a substantial deposit or agreeing a construction start date.

1. House extensions: understanding the new 45m² limit

The 2026 amendment increases the area limit for a qualifying rear extension from 40m² to 45m². It does not introduce a general exemption for building an extension anywhere around a house. Official source

Under Class 1, relevant previous extensions built after 1 October 1964 count towards the total, including extensions that received planning permission. At least 25m² of private open space must remain. Separate conditions govern upper-floor areas, heights, windows, boundary distances and use of the extension roof. Official source

An existing extension can reduce the remaining allowance

As a simple illustration, a relevant existing 20m² extension could leave 25m² of area headroom, not another 45m². That is only an area calculation; all other requirements must still be satisfied. Official source

Before requesting quotations, ask your designer to establish the previous extension history and prepare a clear proposed layout.

For budgeting, read our House Extension Costs Ireland guide. When the scope is ready, you can request suitable builders in Ireland.

2. Garden rooms, offices and sheds: the 30m² exemption

The revised garden-structure exemption increases the combined area allowance to 30m² for qualifying structures such as sheds, stores, home offices and gyms. Official source

The total includes relevant existing structures. Nothing may be placed forward of the house’s front wall, and at least 25m² of private open space must remain. Height limits are 4m for a tiled or slated pitched roof, or 3m otherwise; finish conditions also apply. Crucially, Class 3 does not permit human habitation. Official source

A garden office is not the same as a granny flat

A building marketed as a “garden room” does not automatically qualify as a bedroom, rental flat or separate dwelling. Intended use matters, and the rear-garden dwelling exemption has different requirements. Trade Source IRE

When speaking with suppliers, describe exactly how you intend to use the building. Do not rely on the product name as evidence of planning compliance.

For the separate residential route, see our Granny Flat Planning Permission Ireland guide.

3. Granny flats and rear-garden homes: the new Class 3A exemption

Class 3A introduces an exemption for certain detached auxiliary dwellings behind a principal house. The Government’s overview describes qualifying accommodation of 32–45m², linked to the main house’s services. Official source

The detailed conditions are important:

The principal house must be the owner’s sole or main residence when development starts. The new dwelling must be permanent, occupied in conjunction with the main house, and cannot be sold separately or used for short-term letting. The exemption is unavailable where the principal house has been subdivided. Official source

The dwelling must be at least 32m²; together with relevant existing Class 3 structures, the total cannot exceed 45m². Height is limited to 4m with a tiled or slated pitched roof, or 3m otherwise. At least 25m² of private open space must remain, with minimum 0.6m separation requirements for the structure and its windows. Official source

Independent pedestrian and/or wheelchair access must be provided within the property, without creating a new road access. Separate utility connections are not permitted; specific wastewater-capacity and percolation-area conditions apply. Official source

You must notify the council

For Class 3A, notification is required at least 14 days before work begins. The works must be commenced and completed within the relevant period, which ends on 31 December 2030. Official source

Do not treat notification as a replacement for checking compliance. Have your designer assess the complete proposal against the regulations before ordering a unit.

The Department’s building guidance also makes clear that an auxiliary dwelling must meet Building Regulations and Building Control requirements. A planning boundary distance alone does not settle separate fire-safety design requirements. Official source

4. Can you divide a house into two homes without planning permission?

The new Class 1A exemption can allow subdivision of a house, but it is not an unrestricted route to converting a property into several flats.

The regulation limits the result to two units in total. Each must have at least 32m² of floor space and be self-contained, without relying on shared internal accommodation other than access. The exemption cannot be used where a detached house has already been constructed, erected or placed in the rear garden. Official source

This class also requires 14 days’ advance notification and completion within the relevant period ending 31 December 2030. Building Regulations and Building Control obligations remain applicable. Official source

Before requesting a construction price, our recommendation is to commission a layout showing how each unit will function. Ask the designer to address access, services, fire safety and the applicable compliance requirements—not just where the new dividing wall will go.

5. Attic conversions, dormers and rooflights

The regulations introduce separate provisions for side/rear dormers and rooflights on the front roof plane.

Side and rear dormers

Class 1B covers qualifying dormer roof extensions and dormer windows to the side or rear of a house. The combined internal volume must not exceed 30 cubic metres. The dormer cannot rise above the roof ridge, and an eaves setback of at least 20cm is required. Official source

That limit is measured in cubic metres, not square metres. A front dormer is not included in this particular exemption. Official source

Front rooflights

Class 1C permits a maximum of two rooflights on the existing front roof plane. Each must be no more than 100cm long and 90cm wide. Official source

For project planning, read our Attic Conversion Costs Ireland guide. You can also explore carpenters and roofing contractors for the relevant work.

6. External wall insulation: what is now exempt?

Class 63 covers external wall insulation and necessary associated work.

The insulation must not exceed 150mm in thickness on the front, rear or gable walls, must not encroach on a public road, and must not alter the appearance so that it becomes inconsistent with the character of the building and neighbouring structures. Official source

Do not assume that every proposed insulation build-up falls within this exemption. Ask the designer or installer to confirm the dimensions and details being proposed.

You can request insulation contractors through Trade Source Ireland and read our SEAI grants guide for information about the separate funding process.

7. Heat pumps: more flexibility over location

The amended heat-pump exemption removes the previous prohibition on installations on, or forward of, the front wall or roof of a house. It replaces that condition with a prohibition on encroaching onto a public road. Official source

Other conditions remain, including a combined area limit of 2.5m², restrictions on ground-level alterations, mounting clearances and noise.

The stated noise limit is 43dB(A), or 5dB(A) above background noise, whichever is greater, measured at the nearest neighbouring inhabited dwelling. Official source

Our recommendation is to have the installer assess the proposed location before installation, rather than choosing it solely because it is convenient for pipework.

8. Bicycle storage, bin stores and chimney removal

Bicycle and bin storage

Class 62 allows qualifying domestic bicycle or bin storage structures up to 3.5m², with a maximum height of 1.4m.

For front-of-house installations, the structure must be set back 0.6m from the house’s front wall and must not reduce the proportion of the front garden retained as open space by more than 50%. Official source

Chimney removal

Class 2A permits certain chimney removals. It does not cover removing a chimney that forms part of a joint stack with a separate dwelling. Replacement roof finishes must match the existing roof, and protections for nesting birds and protected animals, including bats, remain applicable. Official source

Before proceeding, ask an appropriately qualified professional to assess the structural implications and any remaining appliances or flues.

Planning exemption does not remove Building Regulations

This is particularly important for homeowners considering a new dwelling or substantial conversion.

Planning and Building Control are separate matters. Depending on the work, notices, certificates and other compliance procedures may be required. Your local authority’s Building Control section can explain what applies to the project. Official source

For auxiliary dwellings, the Department’s guidance expressly requires compliance with Building Regulations in the same manner as new dwellings. It also identifies responsibilities for owners, designers and builders. Official source

Ask for a written explanation of the compliance route before construction begins.

A quotation describing a project as “planning exempt” should not be treated as a complete answer about its design, safety or certification.

How can you confirm whether your project is exempt?

Where the position is uncertain, you can request a Section 5 declaration from the relevant planning authority.

This is a formal route for determining whether a proposal constitutes development and whether it is exempt. Dublin City Council’s guidance explains that an application should include the relevant site information and maps. Official source

Ask your designer to help prepare a clear description, drawings, measurements and intended use. Also have them check the property’s planning history and whether protected-structure or conservation-area restrictions need particular attention. Official source

Our advice: a project-specific assessment is a better basis for committing money than a general statement from a supplier that “these never need planning”.

Before hiring a builder: our practical project checklist

We recommend preparing a short project pack before approaching contractors.

Describe the intended use and scope. State whether you want an extension, office, separate dwelling, attic conversion or insulation upgrade. Include drawings, measurements, photographs and the site location.

Record the planning and compliance position. Keep any professional assessment, declaration, notification and relevant correspondence together. Identify who will manage the design and required completion documents.

Request comparable written quotations. Ask contractors to price the same drawings and specification. Request separate information about materials, VAT, exclusions, waste removal, access equipment, payment stages and programme.

Our tradesman certificates and insurance checklist and guide to avoiding cowboy builders provide further questions to ask before appointing someone. Trade Source IRE

How Trade Source Ireland can help

Once you understand what your project involves, finding available trade professionals is the next step.

Trade Source Ireland does the legwork of helping you find potentially suitable tradesmen. We review your enquiry and use our network and trade-industry relationships to help identify options where available. Trade Source IRE

For extensions, renovations and conversions, start with our Builders Ireland page. For specialist requirements, you can browse our trade categories or explore businesses through the Tradesmen Showcase. Trade Source IRE

It is free to enquire. Where available, we aim to provide three to five suitable options, with no obligation to proceed. You choose whom to appoint and agree the scope, price and terms directly. Availability depends on the trade, location, timing and project requirements. Trade Source IRE

Trade Source Ireland does not determine planning exemptions or certify a proposed design. Obtain the appropriate planning and technical advice, and independently confirm the contractor’s insurance, experience, qualifications and suitability.

Support for builders and main contractors

Already managing a project and need a specialist trade or additional crew?

Our Find Subcontractors Ireland service accepts requirements from builders, main contractors, developers and project managers. Include the trade, site location, start date, expected duration and whether the requirement is labour-only or supply-and-fit. Trade Source IRE

Frequently asked questions

Did these planning exemptions begin in September 2026?

No. The regulations came into operation on 27 July 2026. The Government announcement’s September update date should not be confused with the legal commencement date. Official source

Can I use the exemptions without meeting every condition?

No. A proposal must satisfy the applicable description, conditions and limitations. Meeting the headline area limit alone is not enough. Official source

Can I subdivide the house and also use the rear-garden dwelling exemption?

The regulations contain restrictions preventing these exemptions from being combined in that way. Check the existing property arrangement and proposed works before choosing either route. Official source

Does “planning exempt” mean I do not need professional input?

No. It does not resolve Building Regulations, structural design or Building Control requirements. For a substantial project, establish the required professional roles and documentation before starting. Official source

Planning an extension, conversion or home upgrade?

Start with the property-specific checks. Then prepare a clear brief for the people who will price and carry out the work.

When contacting Trade Source Ireland, include your county and town, project type, approximate size, planning status, drawings if available, timeframe and budget.

Request a Tradesman →

Free to enquire. No obligation. We do the legwork.

Official sources and further reading

Overview and commencement: Department of Housing 2026 circular and South Dublin County Council commencement guidance.

Regulations: S.I. 338/2026 — extensions and garden structures, S.I. 339/2026 — house subdivision, S.I. 340/2026 — auxiliary dwellings, S.I. 341/2026 — storage and insulation, S.I. 342/2026 — heat pumps, S.I. 343/2026 — chimneys, S.I. 344/2026 — dormers and rooflights.

Project-specific checks: Dublin City Council Section 5 declarations and Local Government Ireland Building Control.

This guide summarises the principal changes and selected conditions; it is not an exhaustive legal checklist or project-specific planning, engineering or Building Control advice. Information was checked on 3 October 2026. Confirm the current requirements with the relevant authority and appropriately qualified professionals before committing to construction.