With clients looking to take on a design project a common question which we find is ‘What are the building costs per m2’. At JEArchitecture we find this question arises either at the start of a project or after the initial design stage when a client has decided they want to expand the original scope construction of a new build or an extension. The RIAI (The Royal Institute of the Architects of Ireland) in the middle of each year publishes information about Construction Costs in Ireland to help clients with guidance on building costs. These Building Cost Guidelines are based on standard site conditions, specifications, client requirements etc.

There are of course a number of factors which may increase/decrease the cost ranges noted, such as non-standard site access, site conditions, specifications, finishes, etc. We as architects have a broad knowledge on how to help manage these costs and discuss with the client the benefits and negatives of various material choices or finishes and through clever design can help the client realise their dream home while managing these costs to a specified budget.

We at JEArchitecture are a design-driven architectural practice and also a registered architectural practice of the RIAI located in North County Dublin. The RIAI advise strongly that you consult with a registered Architect/Practice as early in your design adventure to get more accurate costings as the below are just a guideline to various building costs. If you’re planning on taking on a design project you should take the time to work out what the cost of building is for the design and scale you have in mind. We at JEArchitecture can then advise how this can be achieved to meet the budget you have set aside.

The RIAI information is for guidance only using average costs for the building types as set out, current for 2019-2020. A note of caution is issued with them due to continuing inflationary influences and consumers and clients should be aware of the increasing level of cost inflation within the industry which is much higher than general inflation.

The tables below are a summary of the RIAI Cost Guidelines 2019. The Guidelines highlight a number of exclusions and conditions and the summary below should be read in conjunction with the full document. The document can be downloaded here.



These guidelines only give a guideline on construction costs however the bottom line is, it’s impossible to get an idea of the build cost until you have construction drawings with exact specifications, including lighting schedule, heating system, ventilation, etc. Spending money on a registered architects services and dedicating your time to the project at the beginning will pay off in the long run.

In reality, few people will have everything chosen at this stage, and it’s true that the price of your skirting boards won’t have a huge impact on the overall budget. However if you leave too many items in the ‘to be determined’ column you can’t expect to get an accurate figure.

To get around this, PC (prime cost) sums are often used, it’s a price allocated to items in the ‘to be determined’ column, which often consists of things like the kitchen. At JEArchitecture we provide this in our service to try to make the building process as easy as possible for you. PC sums are just approximations and you will have to pay for the difference.

Finally they’re are a few Building cost variables which ill outline below –

      • 1. Design – Depending on the building form the cost of the build can vary. It is cheaper to construct a house which is square or rectangular in plan, fewer breaks in the roof and what materials are chosen to clad the external walls of the building.
      • 2. Building Management – There are generally three ways in which a building project can be managed. The first is done by nominating a main contractor however this tends to be the most expensive route. The second is to hire a project manager, which we at JEArchitecture provide in our services. This service is less of a headache for the client as the architect in question will organise appointing a builder and sub-contractors, organising pricing, and on site inspections of the works. This usually works out as best value for the client as the time taken to organise everything is lessened with the role of the architect. Finally the cheapest option is to self manage or ‘Self Build’. This involves managing all aspects of the project yourself however this requires long periods of time of work and not to mention the stress that comes with it.
      • 3 Site Conditions – Wether its a new build or extension your foundations could cost a lot more than anticipated or you may require an elaborate drainage scheme; this will all depend on what lies beneath, which you won’t know until you start digging. A level site with easy access to services (water, drainage, electricity, roadway, gas, telephone, cable) will also cost less to get connected. Access during construction must also be factored in – building additional routes and/or hiring specialist equipment may be required if the site is hard to get to.
      • 4 Sourcing of Materials – This involves shopping around or extensive research into various elects such as windows, kitchen or sanitary ware to help reduce costs. Your architect will have an extensive knowledge of products and companies which could be used for specific looks or budget restraints so trust your architect and discuss these various options during the design and Tender process.
      • 5 Contingency –  Without one you could run into serious trouble, this fund is set aside to cover the costs of unforeseen problems as mentioned under site conditions as well as various other issues which may arise such as design changes by the client, material changes, sourcing issues etc. On a new build 10% to 15% of the build cost is usually set aside for unforeseens; on a renovation project you should consider doubling that, especially if you’re doing up an old house.

Note that the above provisional construction costs do not include Vat, Professional fees, planning costs or fees, inflation, furniture. For accurate costs please contact JEArchitecture as we would be more than happy to discuss an upcoming project with you.