How Much Does an Extension Cost Per M2 in Ireland?

Matt Keane
October 31, 2023

Are you thinking about making your home bigger in Ireland but worried about how much it might cost? We've found that, on average, adding one floor to your house can cost between €1,900 and €2,500 for each square metre.

In this blog post, we want to help you understand why these costs can vary. It depends on things like where you live, how nice you want it to look, and how big you want the extra space to be. Plus, there are some permits you might need.

So, let's get started and figure out how to make your dream home extension a reality!

Key Takeaways

  • The cost of a house extension in Ireland can range from €2,500 to €3000 per square metre, depending on factors like location and quality of finish.
  • Factors such as the size of the extension and necessary permits can also impact the overall cost.
  • Investing in a well-planned and executed extension has been proven to add significant value to properties in Ireland.
  • It's important to consider additional costs like planning permission fees and architectural fees when budgeting for an extension.

Factors Contributing to House Extension Costs

Several factors can greatly influence the costs of house extensions in Ireland this year, including location, quality of finish, size of extension, and the necessary building permits.


The location of your house matters a lot. Some areas in Ireland have high building costs. Other places may be cheaper. It's because the price of materials and labour can change from one place to another.

Living in a busy city may also make it hard to bring in big trucks or tools for the work. So, the cost could go up. Always keep this in mind when you plan your budget for an extension.

Quality of finish

The quality of the finish is an important factor to consider when determining the cost of your house extension in Ireland. The level of finish you choose will impact the overall price per square metre.

If you opt for a standard finish, which includes basic materials and fixtures, you can expect to pay around €1,900 to €2,300 per square metre. On the other hand, if you want a high-spec finish with premium materials and luxurious features, the cost can range from €2,000 to €2,500 per square metre.

It's essential to decide on the level of finish that suits your style and budget before finalising your extension plans.

Size of extension

The size of your extension is a key factor that will influence the cost. Generally, larger extensions tend to be more expensive than smaller ones because they require more materials and labour.

On average, a single-storey extension in Ireland can cost around €40,000, while a two-storey extension can cost upwards of €100,000. It's important to carefully consider the size of your desired extension and how it aligns with your budget before starting the project.

Building permits

Getting the necessary building permits is an important step when planning a house extension in Ireland. These permits ensure that your project meets local regulations and safety standards.

It's crucial to obtain the required permits before starting any construction work to avoid legal issues and penalties. The cost of building permits can vary depending on factors such as the size and complexity of your extension, but it is an essential investment to ensure a smooth and compliant construction process.

Don't forget to include permit fees in your budget when estimating the overall cost of your house extension in Ireland.

How Much Does It Cost to Extend a House in Ireland?

The cost of extending a house in Ireland can vary depending on factors such as size, location, and quality of finish. In general, the standard finish for an extension costs around €1,900 to €2,300 per square metre, while a high-spec finish can range from €2,000 to €2,500 per square metre.

So, it's important to consider these costs along with any renovation expenses for the existing house when planning your extension project in Ireland.

Standard finish:  €2,500 to €3000 per square metre 

For a standard finish, the cost of extending your house in Ireland is between €1,900 and €2,300 per square metre. This price includes materials and labour for the extension. Keep in mind that this is just an average cost range and the actual price may vary depending on factors like the size of the extension and the location of your property.

It's always a good idea to consult with professionals like architects or builders to get accurate estimates for your specific project.

High-spec finish: €2,000 to €2,500 per metre sq

For a high-spec finish, the cost of an extension in Ireland can range from from €2,500 to €3000 per square metre This means that if you want top-quality materials and finishes for your extension, you should budget accordingly.

So, keep in mind that this price does not include any additional costs, such as planning permission fees or architectural fees. It's important to consult with professionals to get accurate estimates and ensure your project stays within budget.

Cost of extension Ireland, including renovation costs to existing house

The cost of extending a house in Ireland, including renovation costs to the existing house, can vary depending on various factors, such as the size of the extension and the level of finishes.

On average, a single storey extension in Ireland can cost around €40,000, while a two-storey extension can cost upwards of €100,000. The Royal Institute of Architects in Ireland (RIAI) has published a cost guide that provides average costs for extensions in Ireland.

It is important to consider additional costs, such as planning permission fees and architectural fees, when budgeting for an extension in Ireland. Consulting with professionals like architects and builders can help you get accurate cost estimates and ensure your project stays within budget.

Do Home Extensions Add Value to a Property in Ireland?

Home extensions have been proven to add significant value to properties in Ireland, making them a worthwhile investment for homeowners. The return on investment can vary depending on factors such as the location and size of the extension, as well as any necessary permissions and regulations that need to be followed.

However, it is important to note that there are limits on the maximum size of a home extension allowed in Ireland.

Proven return on investments

Investing in a home extension can be a smart financial move for Irish homeowners. It has been proven that extensions can add value to your property, which means you could see a return on your investment when it comes time to sell.

Studies have shown that well-designed and properly executed extensions can increase the market value of a home. This is especially true if the extension adds additional living space, such as an extra bedroom or a larger kitchen.

By expanding your living space, you are not only improving your own comfort but also making your home more desirable to potential buyers. However, it's important to keep in mind that factors like location and quality of finish will also influence the return on investment.

So, before embarking on an extension project, it's crucial to consult professionals and calculate all costs involved to ensure you make informed decisions that will maximise the potential returns on your investment.

Permissions and regulations

Before starting your house extension project in Ireland, it is important to be aware of the permissions and regulations involved. You may need planning permission from your local authority, depending on the size and scope of the extension.

It's advisable to consult with professionals such as architects and builders who can guide you through this process. Additionally, there may be certain building regulations that you must adhere to ensure safety and compliance.

These regulations cover areas such as structural integrity, fire safety, energy efficiency, and accessibility. By understanding and following these permissions and regulations, you can avoid any potential issues or delays during your extension project.

Maximum size of a home extension

The maximum size of a home extension in Ireland can vary depending on factors such as local planning guidelines and regulations. It is important to consult with professionals, like architects and builders, who are knowledgeable about the specific requirements in your area.

They can help you determine the maximum allowable size for your home extension project. By following these guidelines, you can ensure that your extension meets all necessary regulations and permits while maximising the space you have available for your needs.

Final Words

The cost of an extension per square metre in Ireland varies depending on factors such as location, size, and quality of the finish. On average, a standard finish can cost around €1,900 to €2,300 per square metre, while a high-spec finish can range from €2,000 to €2,500 per square metre.

So, it's important to consider additional costs like permits and renovations when planning for a house extension. However, consulting professionals and using resources like the RIAI cost guide can help homeowners get accurate estimates for their project.

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*FYI, parts of this blog post were drafted by artificial technlogy. But rest assured, it's been thoroughly researched, edited, reviewed and me & my team.

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