Life Home & Garden

Wednesday 16 January 2019

Does a porch or a garage need planning permission?

If you are considering changes to your home, work with a registered architect. Check on, the registration body for architects in Ireland
If you are considering changes to your home, work with a registered architect. Check on, the registration body for architects in Ireland


Query: We have just bought a house and would like to build a garage and porch. Do we need planning permission?

Answer: Generally, the provision of a garage and a porch within the boundaries of a domestic house would be deemed to be exempted development within the relevant planning legislation, provided they both comply with certain conditions and limitations as set out in the legislation.

What is exempted development?

The exempted development provisions within the planning acts are a great instrument as they allow certain works to be constructed without having to go through the planning process. However, if you carry out works and do not satisfy the conditions and limitations of the exempted development criteria, there is a possibility of enforcement proceedings being instigated and you may not be able to obtain an 'opinion on exemption from planning permission' from an architect which could affect a future sale. Unfortunately, some house sales have fallen through or been delayed due to the documentation not being in order in relation to planning.

What if my house is a protected structure?

If your house is a protected structure, the works you propose will not come under the exempted works provisions. Any work of substance to a protected structure is likely to require planning permission.

Building a porch

Generally, porches are classified as exempt development provided that they measure less that 2sqm internally, and are no higher than 3m for a flat roof construction and 4m for a pitched roof construction. The porch must also be set back a minimum of 2m from any road.

Building a garage

A garage that measures less than 25sqm in area would be exempted development, provided it is not higher than 3m in the case of a flat roof or 4m in the case of a pitched roof construction; not forward of the front wall of the existing house; and the finishes generally conform to those of the house.

If there are existing sheds, greenhouses or stores already constructed within the property, the total area of all these structures and the new garage area together should not exceed 25sqm. Also, the new garage must not result in the private open space of the house - to the rear or side - being reduced to less than 25sqm. The garage must not be used for keeping animals or lived in by the owners of the house.

Interestingly, you can convert an existing garage if it is attached to a house into habitable space without permission. However, it must not result in the overall extended development of the original house being increased by more than 40sqm in order to comply with exempted development provisions. You would also need to comply with provisions on location of windows.

It is recommended that you check any planning conditions attached to the original permission for the house to ensure any additional work, post permission, was not excluded from general exempted development provisions.

For a fee of €80 you can request a Section 5 declaration from a planning authority indicating whether or not the proposed works require permission. However, you need to provide sufficient information, probably drawings, so the area planner can fully assess the proposed works.

Building is a complex matter and it's very easy to make an error over exempted development. I'd recommended you engage a registered architect who can give you an informed opinion as you may require an exemption or compliance certificate at a later date and they often will see solutions or opportunities not immediately apparent to the untrained eye.

If you are considering changes to your home, work with a registered architect. Check on, the registration body for architects in Ireland.

  • Paula M Murphy, MRIA, is an architect working mainly in Tipperary and Dublin;
  • Do you have a design dilemma? Email your problem to
  • Advice is for guidance only and readers are advised to seek professional assistance for any proposed project.

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