Kieran McCarthy: Where to begin an extension

Before starting an extension, make sure you know what you need

House Construction Framing Gradating Into Finished Kitchen Build. WX040223stock

Hi Kieran I would like to extend my kitchen… where do I start please? Do I start by getting an architect? Or a builder? Do I need planning? Please Help! Thank you 

Mark Nolan, Limerick

Hello Mark.

Thank you for this question. I am sure since Covid in particular many people are looking at their homes and imagining how their lives would improve if they just had some more quality space. But where to start?

I grew up in a housing estate in Midleton in the 1980s. In those days everyone seemed to be adding some sort of an extension or other to their homes. It was like an arms race. Someone would add a glass sliding door to their porch, it caught on. Next a pitched roof over the flat roof, the masses followed. Finally the attic conversion, copy and paste up and down the road.

There were stories of a small builder entering the estate and leaving five years later having modified most of the houses in some way or other. So is the small builder the best person to start with in these instances?

In the past, we used to build extensions in Cork. I remember being asked by one lady to have a look at her house. Though she had extended her kitchen about 10 years previously, it really wasn’t working. She had engaged with a small builder who had told her she wouldn’t need an architect as it was simple enough and the architect would just cost too much. The end result was a very significant investment in a body of work in her family living space which never really offered any real long-term value.

Kieran McCarthy: 'When the architect and engineer have communicated and both are happy that their drawings are complete, this is when a builder steps in.'

When designing an extension, you really need to look at the existing house. Assess what is working, what is lacking, and then (if necessary) add to compensate. This requires a spatial analysis by a competent architect. Yes, architects will be concerned with the look and feel of the extension (which will likely cost more to build) but architects always start with floor plans and thus a study of how best to use the critical space in your home.

When it comes to planning permission your architect will assess if your extension will require a formal planning application or if indeed it is exempt. (In most cases a simple single-storey extension at the rear of your property under 40m2 in area will not in fact require planning permission at all but check with your design team).

Once the extension has been fully designed and signed off you are now ready to liaise with an engineer. Whereas the architect is expert in spatial design and planning permission, a structural engineer will detail the ‘nuts and bolts’ of the project in terms of buildability. He will design the foundations, the steel beams over the windows, the roof structure and if any walls need to be knocked in your existing house he will ensure that any necessary beams are inserted to maintain the existing structural integrity.

When the architect and engineer have communicated and both are happy that their drawings are complete, this is when a builder steps in. He takes the finished set of drawings and he can now build the extension armed with the best spatial design and structural detail to execute the build. The engineer will call periodically to site checking the excavated ground condition before the foundations are poured, check the quality of the blockwork and cavities as the walls progress, signing off on the roof and indeed monitoring the tie-in between the new extension and the existing building when all the opening up takes place. He is essentially ensuring that the building works are complying with building regulations, planning permission (if necessary) and best practice.

If you really wanted to push the boat out you could engage with an interior designer to help you with a kitchen layout, floor and wall finishes and of course the dreaded paint colours but this is somewhat discretionary depending on your own tastes and budget.

If you are finding the thought of managing all these professionals a daunting task there are now several design and build firms (professional building companies who bring an architect and engineer together as part of their team) to help streamline the overall management of the project and with the right team, this can lead to a very successful and less hands-on project for you but, as in all cases when dealing with investments of this size, check the references of everyone you are using and if you have to invest a little more to be more comfortable with your team, remember you will only get one chance to do this right.

Kieran McCarthy is a Building Engineer with KMC Homes bespoke home builder, serving Cork and Limerick. He is also co-presenter of the RTÉ property show Cheap Irish Homes.

Follow Kieran on instagram @kierankmc for more home-building information, tips and Q&A advice.

Tune in to Kieran’s new podcast, Built Around You on Apple Podcasts and Spotify and on the Built Around You Youtube channel.