What is the 45m² planning exemption in Ireland?

On 21 April 2026, the Irish Government announced a proposed new planning exemption allowing homeowners to build a detached habitable unit of 32–45m² in their garden without full planning permission. The unit must be linked to the principal home's services and cannot be rented out under standard tenancy arrangements. As of May 2026, this is announced but not yet signed into law — it is undergoing environmental assessment before going to the Oireachtas for ratification.

Is the 45m² exemption in effect yet?

No. As of May 2026, the exemption is proposed and announced but not yet enacted into law. The regulations must complete an environmental screening assessment, then be approved by both Houses of the Oireachtas. Until that happens, the current rules apply: a detached habitable structure requires full planning permission, regardless of size.

Can I rent out a 45m² garden unit?

Under the proposal as announced, units built under this exemption fall outside the scope of the Residential Tenancies Acts. This means normal landlord-tenant protections would not apply. Tax arrangements, including interaction with Rent-a-Room relief, are being considered as part of the Budget process separately. If rental income is your goal, check the final regulations carefully before proceeding.

What size and location conditions will apply?

The proposed conditions mirror the current exempt-development framework: the unit must be between 32m² and 45m² in floor area; it must be a detached structure to the rear of the principal dwelling; it must be connected to the services of the principal house (water, electricity); it must retain adequate rear private open space; and all Building Regulations including energy performance (BER) requirements still apply.

Do Building Regulations still apply even if planning is exempt?

Yes, always. Planning permission and Building Regulations are two separate systems. Planning permission controls whether you can build at all and where. Building Regulations control how it must be built — structural safety, fire safety, insulation, ventilation, energy performance (BER), and accessibility. A structure exempt from planning permission is never exempt from Building Regulations.

45m² Planning Exemption Ireland 2026 — What It Means for Your Garden Home

Q: What BER rating will be required?

The proposed regulations are expected to require a minimum BER A2 rating — the standard that applies to all new residential construction in Ireland. Most quality modular homes from Baltic manufacturers already meet A2 or better when properly insulated and installed. Your supplier should be able to provide a BER certificate or projected rating.

What was actually announced?

On 21 April 2026, Minister James Browne and Minister of State John Cummins announced the most significant update to Ireland's planning exemption rules in nearly 25 years. The announcement followed a public consultation in 2025 that received almost 1,000 submissions — more than half of which related to detached garden units specifically.

The package of changes includes several new exemptions, not just the garden dwelling. Here's the full picture:

Exemption type	Current limit	Proposed new limit	Status
Detached garden dwelling (habitable) NEW	Not permitted — requires full planning	32m² – 45m² detached unit, linked to house services	Proposed Pending
Home subdivision NEW	Not permitted	Up to 1 additional self-contained unit within existing home (min 32m² per unit)	Proposed Pending
Dormer / roof extensions NEW	Not permitted	Dormer roof boxes and/or roof lights on principal dwelling	Proposed Pending
Rear extension (attached)	40m²	45m²	Proposed increase Pending
Garden structures (sheds, offices, gyms — non-habitable)	25m²	30m²	Proposed increase Pending
Rear extension (attached) — current	40m² — currently exempt	—	In effect Current law

⚠️ Important: None of the proposed changes above are in effect yet. The regulations must complete an environmental assessment and then be approved by both Houses of the Oireachtas. Until that happens, the existing rules apply — a detached habitable unit of any size requires full planning permission.

What the 45m² exemption would mean in practice

A 45m² unit is a fully liveable home. To put that in perspective:

A well-designed 45m² home can comfortably include one bedroom, a bathroom, a kitchen/living area, and storage
It's big enough for a granny flat, a returning adult child, a live-in carer, or a rental-free supplementary home
Many modular homes from Baltic and Irish manufacturers sit exactly in the 32–45m² sweet spot — built for this market
At current prices, a 40m² Baltic modular home delivered to Ireland costs approximately €28,000–55,000 depending on spec

The key phrase in the Government announcement is "linked to the services of the principal house." This means the unit must share the existing water and electricity connections of your main home — it's not a fully standalone building, it's an annexe. That has practical implications for site layout and costs.

What the exemption would NOT cover

Units larger than 45m² — these still require planning permission
Units not connected to the principal home's services
Units on land without an existing principal dwelling
Agricultural land or non-residential zones (planning policy varies)
Any unit that reduces rear private open space below the minimum (likely 25m², matching current rules)
Units that overlook or significantly reduce light to neighbouring properties

Building Regulations still apply — always

This is the single most misunderstood aspect of planning exemptions. Planning permission and Building Regulations are two completely separate legal systems.

Planning permission = permission to build (controlled by your Local Authority planning section)
Building Regulations = rules on how it must be built (controlled by your Local Authority Building Control section)

A structure exempt from planning permission is never exempt from Building Regulations. Under the proposed rules, any garden dwelling would need to comply with:

Structure (Part A) — foundations, structural integrity
Fire safety (Part B) — fire spread, means of escape
Energy performance (Part L) — minimum BER A2 rating expected, as applies to all new Irish dwellings
Ventilation (Part F) — adequate fresh air supply
Drainage (Part H) — wastewater and surface water
Accessibility (Part M) — minimum accessibility standards

✅ Good news for modular buyers: Most quality modular homes from Baltic manufacturers (EE, LV, LT) are built to Scandinavian energy standards that comfortably meet Irish BER A2 requirements. When properly installed on an appropriate foundation with correct service connections, they typically comply with Part L without modification. Ask your supplier for their standard BER cert or projected rating.

Timeline — what happens next

Late 2025

Public consultation closes with ~1,000 submissions. Over half specifically relate to the detached garden dwelling proposal.

21 Apr 2026

Government announces the package of proposed changes. Draft regulations prepared under the Planning and Development Act 2024.

Apr–Jun 2026

Environmental assessment (Strategic Environmental Assessment / Appropriate Assessment screening). No confirmed timeline for completion.

Estimated H2 2026

If assessment completes, regulations go before both Houses of the Oireachtas for ratification. Once passed, regulations take effect. An 18-month review is planned post-enactment.

Today

Current rules still apply. Use this time to plan: identify your site, choose a supplier, get a Section 5 declaration from your council to confirm your specific site qualifies once the rules change.

What to do right now

The rules aren't in effect yet, but that doesn't mean you can't prepare. The most useful steps to take now:

Check your site. Measure your rear garden. You need at least 45m² for the unit plus 25m² of private open space remaining. Most standard Irish semi-detached gardens (12m+ deep) can accommodate a 6×7.5m footprint.
Get a Section 5 declaration. Submit a planning query to your Local Authority asking whether a specific proposed structure would be exempt under current or proposed rules. It's free, takes 4–6 weeks, and gives you written legal certainty. This is the most underused planning tool in Ireland.
Talk to suppliers now. Lead times on modular homes from Baltic suppliers are typically 3–6 months from order to delivery. Ordering now (under standard planning permission if needed) puts you ahead of the queue when the exemption comes through.
Check service capacity. Does your existing water supply and electrical connection have capacity for a second dwelling? Get your network operator (Irish Water, ESB Networks) to assess this. It's often the overlooked bottleneck.
Foundation prep. Ground conditions determine foundation cost. A basic concrete slab on good ground costs €3,000–5,000. Poor ground, sloping sites, or sites with clay or peat can push this to €8,000–15,000. Get a ground survey early.

💡 Note on rental income: Under the proposal, units built under this exemption fall outside the Residential Tenancies Acts. This means you could not offer a tenant statutory RTA protections, which limits the rental market significantly. If rental income is your goal, you may be better off applying for standard planning permission for a self-contained dwelling, which does carry full RTA protections and is a stronger asset. Tax implications are being reviewed separately. Get advice before committing.

Frequently asked questions

Can I build now and get an exemption retrospectively?

No. Planning exemptions apply to works carried out after the rules come into effect. Building now without planning permission is an unauthorised development, regardless of what the proposed rules say. Councils actively investigate complaints and can require removal of any unauthorised structure — and there is no time limit on enforcement for habitable dwellings.

Does this apply to existing garden structures I'm converting?

Converting an existing non-habitable structure (e.g. a 25m² garden office) into a dwelling is a change of use, which is a separate planning question. The proposed exemption applies to new detached units. Converting an existing structure would likely require planning permission regardless of the new rules — check with your Local Authority.

Will my property be reassessed for LPT or rates?

Potentially. Adding a habitable unit to your property may affect your Local Property Tax valuation, depending on how Revenue treats the structure. This is a separate assessment from planning or Building Regulations. If you are on a fixed-rate LPT period, the rate is frozen until the next valuation date.

What about rural sites or agricultural land?

The exemption applies to the curtilage of an existing principal dwelling — the land associated with your existing home. Agricultural land without a dwelling does not qualify. Rural planning policy varies significantly by county; in some counties, rural sites with an existing house may have specific zoning conditions that override the standard exempt-development rules.

Do I need an architect or engineer?

For Building Regulations compliance, yes in practice — you need a Assigned Certifier (an architect or engineer) to certify the works to your Local Authority's Building Control office. This is required under the Building Control (Amendment) Regulations (BCAR). Your modular home supplier may assist with this or recommend a certifier familiar with modular construction.

Can I use a Baltic modular home for this?

Yes, provided the unit meets Irish Building Regulations. Baltic modular homes built to ETA (European Technical Assessment) or equivalent standards, with valid CE marking and a BER A2+ rating, are well-suited to this use case. The key additional requirements for Ireland are: correct foundation (screw piles or concrete slab to engineer spec), Irish electrical connection (ETCI certification), and a Completion Certificate from your Building Control authority.

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Sources and further reading

This page is updated as the regulations progress. Last updated: May 2026. This is general information, not legal advice. Always confirm your specific site's planning status with your Local Authority before committing to any build. A Section 5 declaration is free and gives you written certainty.