Do I need Planning Permission for a Granny Flat?

We have a detached garage to the side/back of our home. There is a driveway leading to the garage. One side of this driveway is the side wall of my home, the other side is the side wall of my neighbours home.

We would like to build in to the side passage leading to the garage, this area would be about the same size as the garage. Then at the back of the garage we would extend in to another space, again about the same size as the garage.

So we would be trebling the size of the garage space. Single story.

We would have three bedrooms, a bathroom, open plan kitchen/sitting area.

Do we need planning permission for this?

Also are there any architects out there that specialise in converting small spaces in to habitable homes?

You'll have to work out the measurements but would it really be a granny flat? They're usually attached, this won't be.
I would think you'd need Planning Permission but @Leo knows a lot more about this.

Thanks.

It could be attached if necessary. The front extension to the garage could incorporate our existing side door that is in to our side passage as a door in to the granny flat. Does the door need to be an internal door? From main house to granny flat. Could it be an external door from the main house in to a small private external space under the control of the granny flat. (A private patio area)

In general, planning permission is not required if the extension does not increase the original floor area of the house by more than 40 square metres and is not higher than the house. However, planning permission will be needed if the granny flat is intended to be a stand-alone dwelling.

Building a Granny Flat in Ireland: What You Need to Know​

If it's not attached to the existing house it absolutely needs planning, and to get that you will need a large site to meet minimum standards for a stand-alone dwelling. You will need to separate all utilities, etc.

Planning for granny flats generally state that they must be joined to the existing dwelling and used solely by a family member who has a medical need. Renting is prohibited and once the family need no longer exists, the unit must be amalgamated back into the main house.

If you believe what you propose does fall under exempted development, it's advisable to obtain a declaration of same from the local authority. This will be required if you ever go to sell the property.

See Schedule 2 of the planning act for details of exempted development. If what you're proposing isn't explicitly detailed there, it needs planning.

The extension would be a place for our daughter and child to live. She is separated with no hope of owning their own place. We could incorporate an internal door or door from main house to external patio area.

In time, we could switch properties. We could live in Granny flat and she could live in our larger home.

Permission for a granny flat developments usually require a medical and not a housing need. You need planning for what you have described, best talk to a planning consultant familiar with your local authority to see what might be possible.

The clamor some years back around bedsits and shoebox apartments has made it more difficult to achieve small compliant dwellings.

And in addition to Leo's sound advice.

If you were to argue that you are incorporating the garage into the existing house (as opposed to a separate "granny flat"), you need planning for building out/extending to the side of your house. Planning exemption only applies to extensions to the rear of the house.

If it were me I'd go the route of seeking planning for extending the current house/incorporating the garage rather than the idea of a separate granny flat. To me it would be a lot simpler and people extend their houses all the time (with planning permission if necessary) . The extension can potentially have an internal and outside door.

The mention of "granny flat" raises red flags to me, separate entrances/dwellings, potential to rent it out later etc. creates a lot of potential planning questions.

I'd also seek professional advice on the extension, as it looks like it will need planning whichever way you cut it.