Build cost estimator

The most commonly asked question nowadays is ‘how much does it cost to build a house?’ The answer to that of course is, ‘for what exactly?’

Anyone considering a self-build or renovation/extension project will want to be able to refer to a reasonably accurate build cost per square meter (sqm) or square foot (sqft). This gives you something to work to in principle and generally provides a starting point.

But the reality is, on a home building project it’s impossible to do. You might as well pluck a figure out of the sky. Cookie cutter houses could arguably be priced relatively easily but in our experience Irish self-builders have very different tastes and budgets, and commission unique designs, which leads to a large variation in price.

Self-builders and home improvers also tend to go for higher quality finishes and specifications, which can quickly add quite a bit to that sqm or sqft figure…

So where do you start?

In this article we cover:

  • What influences costs and average cost comparisons by county
  • Pre-building costs
  • What you need before you get the project costed
  • How to get your project costed
  • What is a PC Sum
  • Build cost variables
  • Passive house examples in Ireland

Price variations

The cost of a self-build, extension or renovation will vary wildly not only because of your choice of products/finishes and services/expertise but due to location too. While many items such as timber should cost roughly the same throughout Ireland, there can be as much as 10 per cent to 20 per cent in the difference.

This will seem like very little when you compare the price per item but as soon as you multiply that by the quantity required on your build, the difference will add up. And that’s just for one simple element!

Labour is clearly another deciding factor and in total, you can end up spending nearly 50 per cent more in one area as compared to another. This figure comes from the Society of Chartered Surveyors Ireland (ROI) which publishes a house rebuilding cost guide for insurance purposes; their 2013 edition shows house building prices (detached bungalow) ranging from €108 per sqft in the Northwest area to €159 per sqft in the Dublin area.

Detached bungalow example

To give you more examples, we decided to put together the costs we’ve come across in our case studies over the past couple of years. And the point we’re making about cost variations couldn’t be clearer. In the same county (Cork) and with the same type of project we witnessed two polar opposites whereby an extension project commanded €229 per sqft while a complete refurbishment project came in at €31 per sqft (both figures include build and fit-out costs).

Many projects came in around the 700 per sqm / 65 per sqft range but this figure is so vague it makes little difference if we price it in euros or pounds! Per square metre, over a thousand euros/pounds were easily spent in many new homes we’ve featured in the magazine but a lot also came in at half that.

Pre-building costs

Before you even begin to build there are costs to cover and these will need to be budgeted for. Here’s a synopsis of where it all goes: The Site It’s easy to spend a third or more of your entire budget on the site, including attendant legal and registration fees. Fees will be due to your lender, accountant, designer/architect, structural engineer, and local authority (Planning, Building Control, road opening license, etc.).

Fixed costs include structural warranties, site insurance and possibly personal cover for loss of earnings, removal and storage of furniture, buying new items, selling your existing home, renting while you build. Infrastructure charges include connection to mains water, electricity, sewerage. Borrowing costs in the form of interest repayments (buying the site and bridging for rent and/or the build until you can move in).

Reports If the land might be contaminated you will have to get soil samples analysed, a structural survey may be advisable before you buy, a topological or tree survey may be required if the planners ask for one… the list goes on, all the way to archaeological surveys. For things like this a contingency is vital.

Try our new ‘Selfbuild Cost Calculator’. Fill in details and instantly get a rough estimate for your project

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Written by Astrid Madsen

Astrid Madsen is the editor of the SelfBuild magazine. Email

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