32 to 45 m²
Not less than 32 m². Taken together with any structure previously built in the rear garden under Class 3, not more than 45 m² in total.
Class 3A · S.I. No. 340 of 2026 · in force since 27 July 2026
Irish law changed on 27 July 2026. A permanent detached house of 32 to 45 square metres may now be built in a rear garden with no planning application — only a notification to the planning authority fourteen days before work begins. Kanzler builds that house to Irish Building Regulations and hands over the keys in four months.
What is fixed before you sign
A garden house under Class 3A must be commenced and completed before 31 December 2030. A build that slips is a build that loses its exemption. That is why every number below is a contractual obligation, not an estimate.
Price closed in the contract before manufacture begins. No revision for material costs or site variation within the agreed scope.
From signature to handover, with a late-delivery penalty stated in the contract confirm figure
Structural warranty, in years, carried by the manufacturer confirm term
Engineered as a permanent dwelling — the law explicitly excludes anything temporary, such as a caravan or a mobile home.
Read this before you believe a brochure
Since the regulations were signed, a great deal of marketing has promised a garden unit you can rent out on a short-term platform, or sell on separately as an investment. Both are prohibited by the text of the exemption itself. We would rather lose a sale than have a client discover this after the concrete is poured.
What Class 3A does give you is real, and considerable: permanent, permitted, private accommodation for a parent, an adult child, or a home office — on land you already own, without a planning application, without a boundary dispute, and without the eighteen to thirty-six months a conventional extension would take.
The exemption, in full
Class 3A was inserted into the Planning and Development Regulations by S.I. No. 340 of 2026, signed on 16 July 2026 by the Minister of State and in operation from 27 July 2026. These are its terms, not our summary of them.
Not less than 32 m². Taken together with any structure previously built in the rear garden under Class 3, not more than 45 m² in total.
Four metres for a tiled or slated pitched roof. Three metres for any other roof form.
At least 0.6 m from any wall or party boundary. Any window must sit at least 0.6 m from the boundary it faces.
Private open space reserved for the occupants of the principal house may not fall below 25 m² once the new house is in place.
A notification to the planning authority at least fourteen days before works commence, stating the location, the Eircode and the reason for using the exemption.
No new vehicular or pedestrian access onto a road. Independent pedestrian and wheelchair access must be provided within the curtilage of the principal house.
No separate connection to water or wastewater utilities. Where treatment is non-piped, capacity must meet the additional load under the EPA Code of Practice, and the percolation area may not be encroached upon.
The exemption applies only where the principal house is the sole or main residence of the owner when works begin, and only where that house has not been subdivided.
The development must be both commenced and completed within the relevant period, which ends on 31 December 2030.
Beyond planning
This is where most garden buildings in Ireland fail. Condition 4 of the exemption states it plainly: building control legislation continues to apply in full. A Class 3A house is a new dwelling, and it is treated as one.
Structure, fire safety, ventilation, conservation of fuel and energy, drainage, sound and access. Fire safety is named explicitly in the regulations. A garden room built to shed standards does not meet them.
Because the structure is a new dwelling, a Commencement Notice is lodged with the local building control authority through the Building Control Management System, generally between fourteen and twenty-eight days before work starts. This is separate from, and additional to, the fourteen-day planning notification.
For modern methods of construction, the NSAI Agrément certificate is what Irish lenders, local authorities and building control officers rely on to accept a factory-built house as a permanent dwelling rather than a temporary cabin. Certificates run for five years and are maintained by annual surveillance audit. Kanzler certificate number — to confirm
Irish lenders typically require a structural warranty alongside Agrément certification. Provider and term — to confirm
A Building Energy Rating for the completed dwelling, and, on unsewered sites, demonstrated treatment capacity for the additional load under the EPA Code of Practice for Domestic Waste Water Treatment Systems.
The house
Kanzler manufactures in a single atelier of precision in Portugal and delivers across Europe. The Irish garden house is dimensioned to sit inside Class 3A from the first drawing — height, footprint and boundary clearance are constraints of the design, not compromises made on site.
| Specification | Irish garden house |
|---|---|
| Floor area | 32 m² to 45 m², configured to the remaining garden area on the site |
| Roof and height | Within 4 m pitched, or 3 m for a flat roof, measured to comply with Class 3A |
| Boundary clearance | Set out at no less than 0.6 m to any wall or party boundary, windows likewise |
| Structure | Precision modular engineering, manufactured and finished under factory control |
| Services | Drawn from the principal house — no separate utility connection, per condition 12 |
| Layout | Bedroom, bathroom, living and kitchenette within the permitted envelope confirm plan |
| Energy | Built to Part L; rating confirmed by BER assessment on completion confirm target rating |
| Programme | Four months from signature to handover |
| Price | Fixed in the contract before manufacture confirm figure |
For estate agents and auctioneers
Every house on your books with a rear garden, an owner in occupation and 25 m² to spare now carries an entitlement it did not carry in June. That is a conversation with a vendor, a reason for a valuation, and an argument for a buyer weighing two similar houses. We would like Irish agents to be the ones who bring it.
One showroom per territory, with leads routed by postcode from the central hub. We do not place two partners in the same catchment.
Refer a client and be paid on completion, or take the showroom for your territory and hold the client relationship yourself. confirm commercial terms
Planning notification, Commencement Notice, building control compliance and certification are carried by Kanzler. You keep the client.
We approach PSRA-licensed firms only, and we hold your details as business contacts on the public register. One message, and we stop if you say so.
Questions
No planning application is required if every condition of Class 3A is met. You must still notify the planning authority at least fourteen days before works commence, giving the location, the Eircode and the reason for using the exemption. The authority keeps a record of these notifications and reports them annually to the Minister. If any single condition is not met, the exemption does not apply and a full application is required.
Not as a separate dwelling and not on a short-term basis. Condition 3 requires the house to be occupied in conjunction with the main dwelling and prohibits selling or subdividing it separately. Condition 19 prohibits short-term letting outright. Whether any particular family or Rent-a-Room arrangement qualifies is a question for your solicitor and for Revenue, and we will not advise you on it.
Not on its own. It transfers with the principal house. It is permitted accommodation attached to your property, not a separate title.
Two thresholds decide it. The house itself must be at least 32 m², and at least 25 m² of private open space must remain for the principal house afterwards. Add the 0.6 m boundary clearance on the relevant sides. We survey before anything is signed and tell you plainly if the site does not work.
No — and it may not have one. Condition 12 prohibits a separate utility connection. Services come from the principal house. On unsewered sites, the existing treatment system must have capacity for the additional load under the EPA Code of Practice, the percolation area may not be encroached upon, and no additional treatment unit may be installed under this class.
The exemption period ends on 31 December 2030, and the development must be both commenced and completed within it. A four-month programme is what makes that deadline comfortable rather than tight.
The only way to decide
Drawings persuade nobody. Stand inside 45 square metres, close the door, and the question answers itself. Book a viewing and we will confirm the nearest house you can walk through.