Property Advice: The planning rules on repurposing that garage

There is a lot to consider when adapting an existing building such as repurposing an underutilised garage.

Hi Brigid,
My wife and I live in a three-bed, semi-detached in Cork. We have one son, who lives in Dublin, and a daughter who is living with her boyfriend and renting elsewhere in the city. They are hoping to save and buy their own place in a couple of years but of course, it’s very difficult to save meaningful amounts while paying high rents. Recently we saw how neighbours of friends of ours converted their garage into a really comfortable self-contained unit for their son. Given that our own garage is just being used as a dumping ground we are now keen to explore doing something similar for our daughter and partner. Our daughter, needless to say, jumped at the idea and is already talking about building on a second storey extension with circular stairway, etc. I’m not sure about all that but would be interested to hear your thoughts on the practicalities — and costs — of two options: a) a more basic conversion, maybe with en suite, where we would all continue to use the main house (to be honest I’m a bit concerned about how this would work in practice), and b) a more ambitious one where the extension is totally self-contained. While I’m sure it would cost a lot more, would it be an investment for the future and a space we could rent out when my daughter and partner move on?
Thank you, Colm.

Hi Colm,

Space is really at a premium these days. Or maybe it always was. The cost of going it alone is very off-putting but when it’s our kids that are looking to purchase their own home, we all want to do our best to help out. And examining how we can adapt an existing building, such as repurposing an underutilised garage is a great place to start. Let’s look at this through your suggested scenarios of (a) and (b).

Under (a) The Planning and Development Regulations 2001 (as amended), Schedule 2, Part 1 Exempt Development — General, Class 1 sets out what your entitlements are regarding converting your attached garage. When you scan through these you will see that there are certain restrictions, and these mainly pertain to potential previous development of your dwelling. If you have not added to your home previously then things are a little smoother. If you have, then get out your measuring tape, or your laser measurer if you’re a tech head, and crunch some numbers.

If you wish to insert an ensuite then look at the same section of the Planning and Development Regulations to see what changes are exempt. These exemptions are with the understanding that you will use this new space as part of the dwelling, ancillary to the dwelling and for the ‘enjoyment’ of the dwelling. All this means that you are still left with one dwelling at the end of works.

Garages are spaces built for a specific purpose. Generally, unless you had a designer that liked to future-proof in case of expansion, they are cold spaces with poor lighting and very often they have no insulation in the walls and have a dropped floor level so you must step down into them. If it’s attached, you will have an internal door that leads into a utility space or circulation corridor. It will likely have a garage door taking over the front of the building, for ease of vehicular access, and this will contain mechanisms for a roller shutter, tilt, or side hinge door. The room is unlikely to have a heating source and may be doubling up as the plant room for the rest of the building. Then, there is the question of what to do with the car and all the other items stored in the space. Yard sale anyone?

Early discussions with a building professional such as chartered building surveyor as well as with plumber and an electrician would be a good place to start before commencing any works. Is extra room needed in the fuseboard? Can the heating system take the extra load onto the existing system, or must you upgrade? Remember, we have moved away from the bare necessities and your daughter, and her boyfriend will probably expect a high level of comfort so you may have to find out what their definition of this is.

The garage door will need to be changed to a window and this may mean that you will have to build up an external wall under the new sill. The internal door may not be situated in the most suitable place so you may consider changing this to have greater connectivity with the main dwelling.

A dropped floor is an advantage as you’ll have the opportunity of running services into the floor as well as adding insulation. Insulation will most likely be required for the walls and where you have no first-floor room above, insulation may be added to the underside of the ceiling where there is room, or at roof level where there is access.

It would be remiss not to mention the possibility of asbestos containing materials (ACMs). It was common practice right up to the 1980s to use ACMs in the ceilings and/or roof of a garage. It may not be limited to these however, so I’d look at the oil burner flue, tiles, or underside of lino, etc. In short get a specialist to do an audit on the entire space before commencing works.

Now to option (b): There is no doubt that with clever design, your existing house is capable of giving more to its users. Creating a self-contained space is always a possibility. However, this brings with it a whole raft of new considerations. Firstly, planning permission will be required to break the property into, what will be to all intents and purposes, a mini terrace.

Outside the obvious physical changes which the existing house will have to undergo to facilitate the addition of a new unit, you must consider the ground it sits on. If urban based, parking facilities may be required. If you have no room, then you’ll be subject to a development contribution for parking.

Private open space requirements will likely mean that your garden will have to be split and part of it allocated to the new unit. This often comes as a surprise to people, but it is to safeguard the integrity of the property for future occupants. Will your extension impact negatively on the neighbour’s amenity by overlooking? Will the extension upset the character of the street or housing estate and be at odds with the layout?

Just for anyone considering this who lives in a rural area, the question arises of whether a second wastewater treatment system will be needed. Is the entrance good enough? Will the local development plan allow such development?

The new self-contained unit will be subject to BC(A)R 2014. That is, it will not only have to comply with all relevant parts of the building regulations, but you will have to appoint a main contractor, design certifier, and an assigned certifier to sign off the works.

There are several legal and financial issues that you would need to consider for either option A or B. These include questions about ownership, the amount of finance you need to raise and who’ll be responsible for the loan/mortgage.

So, plenty of food for thought there and the route you choose will very much depend on your own circumstances, especially your financial resources as well as your future plans for your home.

Brigid Browne is a chartered building surveyor, chair of the Building Surveying Professional Group, and vice chair of the Southern Region of the Society of Chartered Surveyors Ireland;

She is the owner/ managing director of Cashel-based Fortress Planning which offers a range of services including assigned certifier, design certifier, building surveyor and conservation consultancy to clients all over the country. (www.fortressplanning.ie);

If you have a property related query or issue you would like to raise with Brigid, please email: [e-mail]