Building your own home? Here is where it will cost you

An architect and quantity surveyor can help keep you on the right track

In the past, houses were very simple; they were generally square or rectangular with a simple roof and footprint. These houses were straightforward to cost and build. Picture: iStock

DEAR Kieran, My partner and I are looking to build a new home on our farm in West Cork. We have what we believe to be a reasonable budget, judging by what some friends and family members have built for in the past, but we are very new to the whole house building process and everyone seems to have a different opinion on what a reasonable budget is and how much we should pay. It all seems very complicated and uncertain

Can you please tell us what are the key factors that affect the cost of a house and how we could best ensure we are getting the best value when we build?

DEAR Karen and Dave,

So you have unearthed what is possibly one of the hottest construction topics since the invention of central heating.

Kieran McCarthy: 'Though modern houses are much better designed in terms of their use and enjoyment, they will more likely be complex in shape and their position on-site.'

If we take a little step back here, it will be easier to explain how this problem arises, how best to consider house design and how it relates to build cost.

In the past, houses were very simple; they were generally square or rectangular with a simple roof and footprint. In a singular (one-off) house build, the housebuilder would seek a level field on which to build. These houses were straightforward to cost and build.

Nowadays, however, things have changed very much. The biggest difference is that we now (wisely) employ architects to design many of our houses.

Architects will generally design a house from the inside out. They will discuss with you how many rooms you need, your lifestyle requirements and what size family you have/expect before they design your home.

They will also take into account the path of sunlight around your house and, indeed, the views you wish to capture.

Though these modern houses are much better designed in terms of their use and enjoyment, they will more likely be complex in shape and their position on-site.

These houses are often a little smaller than they would have been in the past as architects are generally more space-efficient and they cut down on unnecessary circulation space (hallways/landings) and gone is the ‘box bedroom’ of old, thankfully!

What drives cost per square foot is house size (quantity), house shape (complexity), house specification (quality), scope of work (phasing of some finished items) and house position on your site (ground conditions, driveway length).

So how do you drive value in your new home design?

Firstly, if you are building on your own land, you may have several sites to choose from. If possible, choose one that is as level as possible, free of rock and free-draining (ask the farmer!)

Let your architect know your budget and discuss what is important to you in terms of design.

The bigger a house, the more it will cost as there is simply more labour and material involved, so have an architect size your house adequately but not excessively.

As your architect draws your house, ensure all the major boxes are ticked in terms of the rooms and space you need and then be aware that any significant design enhancements beyond this will add to the cost (corner windows, double height space, vaulted ceilings, glazed links etc).

The bigger a house, the more it will cost as there is simply more labour and material involved.

When your design is finished, I would advise you to get a cost estimate from a quantity surveyor (QS) before you lodge for planning permission. This will give you some idea of what your house will cost to build.

If you find you are over budget (which is very likely), check what the QS has assumed in terms of specification (windows, kitchen, tiles, floors, heating, paving, bathroom ware) to ensure it aligns with your expectations. You may be able to adjust the size a little or phase some of the external works for a year or two (driveway finish, kerbs, external decoration) to help with your upfront build cost.

Getting the design and budget working at the very beginning of your house build journey is crucial and maybe a little stressful, but I would strongly advise you get this right before you lodge for planning permission. Better to adjust your design and expectations while you have time, as it’s much more stressful and expensive when the builders are on site.

Remember, measure twice, cut once!

Kieran McCarthy is a builder and civil engineer and heads up Cork-based KMC Homes, a bespoke home Design and Build firm. He is also a co-presenter on RTÉ’s popular Cheap Irish Homes series.