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Clarcon designs and builds house extensions across Dublin, from single-storey kitchen extensions to full two-storey builds. We manage the whole project under one team, from planning permission through to the finished space, with clear costs and a programme you can plan around.
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The most common extension in Dublin. Extending the back of the house to create a larger kitchen, an open-plan kitchen-living area or a new living room. Rear extensions up to a certain size are often exempt from planning permission, which we confirm before design.
A side extension uses the space along the side of the house, often to widen a kitchen or hallway. Side extensions almost always need planning permission, and we handle that application as part of the project.
A two-storey extension gives you the most space for your money, typically adding living space downstairs and a bedroom or two upstairs. These need planning permission and careful structural design, both of which we manage.
A wrap-around extension combines a rear and side extension to open up the whole back of the house. It is a larger project, but it transforms how a home feels and functions.
A kitchen extension is the most popular reason Dublin homeowners extend. We build the structure and coordinate the fit-out so you get the open-plan kitchen and living space most people are really after.
A dormer extension adds usable space and headroom in the roof. It is a way to gain a bedroom or office without changing the footprint of the house.
Here is how we take an extension from first idea to finished space.
We visit the property, look at the site, and talk through what you want the extension to do. You get honest guidance on what is realistic for your house and budget.
We prepare the design and confirm whether the extension is exempt or needs planning permission. If permission is required, we handle the application. Drawings and structural design are completed before any work starts.
Our trades build the extension to the agreed programme, from foundations to finishes. You have one point of contact throughout.
We snag the work, complete a full inspection and hand over a finished extension that meets the standard we agreed on and complies with Building Regulations.
An extension to the rear of a house is generally exempt from planning permission if it does not exceed 40 square metres in floor area. There are conditions attached:
You will usually need to apply for planning permission if:
Even when an extension is exempt from planning permission, it must still comply with Building Regulations. This covers structure, insulation, fire safety and more. Exempt does not mean unregulated.
The exemption rules have details, and local authorities can interpret them differently. We confirm exactly where your project stands at the design stage, so there are no surprises later. If permission is needed, we handle the application as part of the job. For a fuller walkthrough, see our guide to planning a house extension in Ireland.
| Extension Type | Typical Cost (Dublin) | What Moves The Price |
|---|---|---|
| Single-Storey Rear Extension | €1,900 – €2,500 per m² standard · €2,500 – €3,000 high-spec | Glazing, underfloor heating, finish |
| Single-Storey Side Extension | €1,800 – €2,400 per m² | Roof structure, access |
| Two-Storey Extension | €1,800 – €2,500 per m² | Best space-per-euro, structural scope |
| 20m² Rear Kitchen Extension | €52,000 – €63,000 all-in | Including VAT and professional fees |
| 30m² Rear Extension | €70,000 – €95,000 all-in | Including VAT and professional fees |
Two costs catch homeowners out if they only budget on the per square metre rate. Professional fees, covering architect drawings, structural engineering and the BER assessment, typically add €5,000 to €10,000. And renovation and construction work in Ireland is charged at the reduced VAT rate of 13.5%, which should be included when you compare quotes.
Materials and labour for the structure itself, foundations to finishes.
Architect or architectural technologist, structural engineer, BER assessor.
The reduced rate applied to construction work in Ireland.
A buffer for ground conditions and other surprises.
With property prices high and housing in short supply, more Dublin homeowners are extending rather than moving. An extension gives you the extra space without the cost, stress and stamp duty of buying a bigger house.
A well-built extension can also add value to the property, so the investment works for you if you sell later. The most reliable returns tend to come from extensions that create open-plan kitchen and living space.
Most of all, an extension lets you stay in the home and area you already know, while reshaping the house around how your family actually lives. If your layout already works and you mainly want to modernise, a full house renovation may suit you better than an extension.
Clarcon has built extensions and managed construction projects across Dublin for over 17 years. That experience covers the full job, planning, structural design, foundations and finishes, so you are not coordinating separate contractors yourself.
We are clear about cost and planning from the start. You get a detailed quote and a straight answer on whether permission is needed before any work begins.
And we deliver to a programme. One point of contact, an agreed timeline, and a team that finishes what it starts.
House extensions in Dublin typically cost €1,900 to €2,500 per square metre for a standard single-storey rear extension, rising to €3,000 for a high-spec finish. A 30 square metre rear extension usually lands between €70,000 and €95,000 all-in, including VAT and professional fees.
Many rear extensions are exempt from planning permission if they are 40 square metres or less and meet the conditions. Side extensions, two-storey extensions and larger builds usually need permission. We confirm exactly where your project stands at the design stage.
A rear extension is generally exempt up to 40 square metres, provided at least 25 square metres of garden space remains, and the extension is not higher than the existing house. Two-storey extensions have much smaller exemption limits.
A single-storey extension usually takes around 10 to 12 weeks of construction, depending on size and complexity. Two-storey and wrap-around extensions take longer. Planning permission, if needed, adds time before construction starts.
A well-built extension generally adds value, particularly extensions that create an open-plan kitchen and living space. The return depends on the quality of the build and the local market, so it is worth getting advice before you commit.
Beyond the build cost, budget €5,000 to €10,000 for professional fees. This covers architect or architectural technologist drawings, structural engineering and the BER assessment required after the build.
A two-storey extension gives the most space for your money per square metre, but needs planning permission and more structural work. A single-storey rear extension is simpler and often exempt. The right choice depends on the space you need and your site.
Yes. If your extension needs planning permission, we manage the application as part of the project, working with the drawings and design, so the process is handled for you.
Yes. Exemption from planning permission does not exempt an extension from Building Regulations. The build must still comply with rules on structure, insulation, fire safety and more.
The single-storey rear kitchen extension is the most common. Most homeowners are looking to create an open-plan kitchen, dining and living space at the back of the house.
Yes. Dublin has a large stock of older homes, and we have extended many. Period and protected properties need more careful planning, and any work to a protected structure requires planning permission.
That depends on what you need the space for, your site and your budget. A larger extension is not always better. We give honest advice on the size that suits your home rather than the biggest one possible.
Ready to extend your home with a local team you can rely on? Clarcon designs and builds house extensions across Dublin, from first drawings to finished space.
Fill out the form for a quick response, or call us now for straight advice on your extension. You can also reach us through our contact page.
Request a Free Quote Now!
Want to discuss your next construction project? Fill out the form below and we’ll get back to you as soon as possible.
