Garden home planning exemption is now law — S.I. No. 340/2026, effective 27 July 2026.See what it means for your garden →

What changed on 27 July 2026

Granny flat planning exemption: the 32–45 m² rules in plain English

S.I. No. 340/2026 means a detached granny flat (the statute calls it a house in the rear garden; we call it a garden home) of 32–45 m² no longer needs planning permission. Here is exactly what qualifies, every condition in the statute, what still applies, and how to find out where your garden stands.

Check If My Garden QualifiesSee 32–45 m² floor plans

Unsure whether your project is exempt? Section 5 declarations

A Section 5 declaration answers whether the development described in a request is or is not exempted development. The request goes to the relevant planning authority with the information needed to decide that question. Dublin City Council explains the declaration process.

Dublin City Council’s Section 5 form asks for the subject site, details of the works and a list of supporting plans or drawings. Its assessment covers only the works listed and described in that application. Read the council's Section 5 form.

If the planning position is unclear, discuss the described works with your planning authority or adviser. For the separate Class 3A notification and building-control steps, use our council notification guide.

The six things that matter

How the granny flat exemption works

  1. 01

    32–45 m², detached, in the rear garden

    Class 3A covers a detached house in the rear garden of your main home with a total area of at least 32 m² and no more than 45 m², measured on the external footprint. Any garden structures you already built under Class 3 count towards the 45 m². Front gardens, side gardens and attached extensions follow different rules.

  2. 02

    At least 25 m² of garden must remain

    After the build, a minimum of 25 m² of private open space must be left for the main house — roughly a 5 m × 5 m patch. The unit sits at least 0.6 m from any boundary, windows are at least 0.6 m from the boundary they face, and the height limit is 3 m, or 4 m with a tiled or slated pitched roof.

  3. 03

    Its own access within your garden, not onto the road

    The garden home needs independent pedestrian or wheelchair access inside your property. You cannot create a new gate, entrance or driveway onto the road under this class. Services connect through the main house rather than as new separate connections.

  4. 04

    You live in the main house, and the home stays with it

    The main house must be your sole or main residence when work starts, and it must not have been subdivided. The garden home is occupied together with the main house: it cannot be sold or split off separately, and short-term letting is not allowed.

  5. 05

    Tell the council 14 days before you start

    You send a notification to your planning authority at least 14 days before work begins. It states that you are using Class 3A, confirms the site meets the conditions, gives the reason for the garden home, and includes the location and Eircode. The council records it; there is no application to decide. It is separate from the building control Commencement Notice, which a garden home also needs.

  6. 06

    Finish by 31 December 2030, and build to the regulations

    The exemption runs from 16 July 2026 to 31 December 2030, and the home must be both started and completed inside that window. It must be a permanent building, not a caravan or mobile home. A Class 3A garden home is a new dwelling, so full building control applies. A Commencement Notice goes on BCMS 14–28 days before work starts, and a Certificate of Compliance on Completion is registered before anyone moves in.

Check If My Garden Qualifies

Free instant check — confirmed in person at your no-obligation site visit.

Class 3A · every condition

All 20 conditions, numbered as in the statute

The plain-English line is ours. Open any condition to read the exact wording from S.I. No. 340/2026, or download the statutory instrument (PDF).

  1. 01Relevant periodThe exemption runs from 16 July 2026 to 31 December 2030.
    For the purposes of this exemption, the relevant period begins on the date that this Regulation is signed and ends on 31 December 2030.
  2. 02Commenced and completed in the periodThe garden home must be both started and finished before the end of 2030.
    This exemption shall apply only to development that is commenced and completed during the relevant period.
  3. 03Occupied with the main houseThe garden home is lived in together with the main house. It cannot be sold or split off as a separate property.
    The detached dwelling may only be occupied in conjunction with the main dwelling house and cannot be sold or subdivided separate to the principal dwelling.
  4. 04Building regulations applyBuilding Regulations, fire safety and Building Control rules apply in full.
    For the avoidance of doubt, the relevant building control legislation shall apply (such as Building Regulations (including Fire Safety) and Building Control Regulations).
  5. 05Not a temporary structureIt must be a permanent building, not a caravan or mobile home.
    The construction of the detached house shall not be temporary in nature, such as a caravan or mobile home.
  6. 06HeightMaximum height 3 m, or 4 m with a tiled or slated pitched roof.
    The height of any such structure shall not exceed, in the case of a building with a tiled or slated pitched roof, 4 metres or, in any other case, 3 metres.
  7. 07Size: 32–45 m²Total area at least 32 m² and, counted with any earlier Class 3 structures in the same garden, no more than 45 m².
    The total area of such structures constructed, erected or placed within the rear garden of the curtilage of a detached house shall not be less than 32 square metres. Taken together with any other such structures previously constructed, erected or placed under Class 3 within the said curtilage, shall not exceed 45 square metres.
  8. 08No subdivided principal houseNot available where the main house has already been subdivided.
    This exemption shall not be used in cases where there has been a subdivision of the principal house.
  9. 0925 m² of private open spaceAt least 25 m² of private garden must remain for the main house.
    The construction, erection or placing within the curtilage of the principal house of any such structure shall not reduce the total amount of private open space reserved exclusively for the use of the occupants of the house to less than 25 square metres.
  10. 10No new access onto a roadYou cannot create a new entrance, gate or driveway onto the road.
    No new vehicular or pedestrian access onto a road shall be constructed under this class.
  11. 11Independent access within the gardenThe garden home needs its own pedestrian or wheelchair access within your property.
    Independent pedestrian and/or wheelchair access to the detached house shall be provided within the curtilage of the principal house.
  12. 12No separate utility connectionsWater, wastewater and other services connect through the main house, not as new separate connections.
    There shall be no separate connection to utilities, including water or wastewater utilities, subject to paragraph 13.
  13. 13Septic tanks and percolation areasIf the house uses a septic tank or treatment system, the garden home must not encroach on the percolation area, the existing system must have capacity for the extra load to the EPA Code of Practice, and no new treatment unit may be added.
    In the case of non-piped waste water treatment, the structure shall not encroach on any approved percolation area. On site waste water treatment shall be of sufficient capacity to meet the additional loading and shall comply with the EPA Code of Practice for Domestic Waste Water Treatment Systems. There shall be no additional waste water treatment units installed as part of this class.
  14. 140.6 m from boundariesAt least 0.6 m from any boundary wall or party boundary.
    The structure shall be a distance of not less than 0.6 metres from any wall or party boundary.
  15. 15Windows 0.6 m from boundariesWindows must be at least 0.6 m from the boundary they face.
    Any windows proposed in the structure should be at least 0.6 metres from the boundary they face.
  16. 1614-day notificationNotify the planning authority at least 14 days before work starts, confirming the site meets the conditions and stating the reason for the garden home.
    Subject to paragraph 17, a notification shall be submitted to the relevant Planning Authority not less than 14 days prior to the commencement of the works informing them of the intention to use this Class of exemption, confirming that the site meets the requirements under these Regulations and stating the reason for the intended use.
  17. 17Notification contentsThe notification must give the location and the Eircode of the property.
    A notification under Paragraph 16 shall include the location of the proposed use of this class of exemption and the Eircode of the relevant property.
  18. 18Council recordThe council keeps a record of every notification and reports the numbers to the Minister each year.
    The Planning Authority shall maintain a record of all notifications under this exemption and report annually to the Minister on the number of notifications received under this Class.
  19. 19No short-term lettingThe garden home cannot be used for short-term letting.
    The detached dwelling may not be used for the purposes of Short Term Letting.
  20. 20Owner lives in the main houseThe main house must be the owner's sole or main residence when work starts.
    The exemption shall only apply where the principal dwelling house is the sole or main residence of the property owner at the time the development is commenced.

Source: S.I. No. 340/2026, Planning and Development (Exempted Development (Act of 2000)) (No. 3) Regulations 2026, signed 16 July 2026, notice published in Iris Oifigiúil 17 July 2026, in operation from 27 July 2026. Rules can change — we confirm current eligibility for your site at your free consultation.

Sizes that qualify

Ten layouts drawn inside the band

Every one of our free concept floor plans is between 32 and 45 m² on the external footprint, so each one fits Class 3A. Download them as A4 sheets at 1:50, print at 100 % and pace the size out in your garden.

Browse the floor plans

Before work starts

Two separate steps, both mandatory

  1. 1. The Class 3A notification to your council

    At least 14 days before work starts: your Eircode and location, confirmation the site meets the conditions, and the reason for the garden home. Free, and a notification, not an approval. The owner signs the declaration.

  2. 2. The Commencement Notice on BCMS

    A Class 3A garden home is a new dwelling, so full building control applies. The Commencement Notice and compliance documents go in 14–28 days before work starts, and a completion certificate is registered before anyone moves in.

We prepare and lodge both for you; you sign them as the owner. Questions? Call 089 453 2374 or contact us.

Every council’s form and address, step by step →

Sizes vs the 32–45 m² band

Which Nua Living sizes can be exempt?

2 of our 4 sizes sit within the 32–45 m² band. Exemption still depends on your site meeting the conditions above.

Granny flats explained →Browse the floor plans →Renting it out: Rent-a-Room relief →All garden home FAQs →

Further reading

Planning articles from the blog

All guides →

Good to know

Frequently asked questions

What is S.I. No. 340/2026?+

The Planning and Development (Exempted Development (Act of 2000)) (No. 3) Regulations 2026. It adds Class 3A to the Planning and Development Regulations 2001, exempting a detached house of 32–45 m² in the rear garden of a principal house from planning permission, subject to 20 conditions. It was signed on 16 July 2026, came into operation on 27 July 2026 and runs until 31 December 2030.

Does my garden qualify for the exemption?+

The key checks are: is the site in the rear garden of your main home; will at least 25 m² of garden remain; can the unit sit 0.6 m from the boundaries with its own access inside the garden; do you live in the main house as your sole or main residence; and is the unit 32–45 m². Our online checker gives you an instant indication, and we verify on the ground at a free site visit.

Why is there a 32 m² minimum?+

Class 3A is written for a dwelling, so paragraph 7 sets a floor of 32 m² as well as the 45 m² cap. Smaller garden rooms fall under the separate Class 3 rules for garden structures (up to 30 m² in total), which do not allow anyone to live or sleep in them. All ten of our free floor plans sit inside the 32–45 m² band.

How do I notify the council?+

Send your planning authority a written notification at least 14 days before work starts. It must say you intend to use Class 3A, confirm the site meets the conditions, state the reason for the garden home, and give the location and Eircode of the property. The council forms include a declaration (sole or main residence, no sale or short-term letting) that only the owner can make, so the owner signs; an agent can prepare and lodge it. It is one of two separate steps: the building control Commencement Notice goes on BCMS too. We prepare and lodge both for you; you sign them as the owner. Our Class 3A notification guide lists every council’s form and address.

Can I rent out or sell the garden home?+

You cannot sell it separately: under Class 3A the garden home is occupied in conjunction with the main house and cannot be sold or subdivided from it. Short-term letting is not permitted. Longer stays are another matter: Budget 2027 (6 October 2026) extended Rent-a-Room relief to new detached garden homes of 32–45 m² built under Class 3A, backdated to 27 July 2026. The tax-free annual limit rises from €14,000 to €16,000 from 1 January 2027. Rent-a-Room relief is built around licence arrangements: the person living in the garden home is a licensee, like a lodger, not a tenant. Announced in Budget 2027 and subject to the Finance Act and Revenue guidance, which will set out exactly who qualifies and on what conditions. This is general information, not tax advice — your accountant can confirm how it applies to you.

What if my house has a septic tank?+

The garden home must not encroach on the approved percolation area, the existing treatment system must have the capacity for the extra load under the EPA Code of Practice, and no new treatment unit can be added under this class. We check this at the site visit.

What if my project needs planning permission anyway?+

Then we handle it. For units over 45 m² (like our 48 m² two-bed), sites that miss a condition, or a use the exemption does not allow, Nua Living prepares and manages the full planning application, along with the building control Commencement Notice and completion certificate.

Do I need a BER certificate for an exempt garden home?+

Not by law. The Department’s guidance says a BER is not legally required for a standalone building under 50 m². Building control is different: paragraph 4 of Class 3A says the building control legislation applies in full, including fire safety, and a garden home is a new dwelling. Nua Living homes are designed to BER A0, the top of SEAI’s scale, as a design target. We can arrange a BER assessment if you want one.

Will the exemption change?+

When the Government approved the garden home exemption in April 2026, ministers said it would be reviewed within 18 months. Nobody can say yet what a review will change. What is fixed in law today: S.I. No. 340/2026 runs until 31 December 2030, and a garden home must be both started and finished inside that window.