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February 7, 2025

House Extensions Northern Ireland

As people and families evolve, their needs and lifestyles change too. Consequently, the home that was once working well can become outdated or impractical. This is a typical problem for many of our clients in Northern Ireland – their home is just no longer working well for them or serving their current needs. At Gilmour Architects, we are experts in transforming and extending a home so that it can better serve you and your family’s needs and current circumstances.
Here are some things to think about when undertaking your house extension.

Why Choose a house extension?

Many of our Northern Irish clients love the location that their home is in, so would rather improve what they have and adapt it to their current needs, as opposed to buying a new house in a different area.

Updating your current property means that you can keep the elements of the house that you like, while at the same time make improvements or overhaul the bits that aren’t working so well. For example, adding a larger open plan kitchen/dining/living extension if your current kitchen is detached from the living area or isn’t big enough for your growing family or for entertaining family and friends.

Furthermore, if done right extending your property can be a smart financial decision that can significantly boost your property’s market value. Creating an extension will also allow you to add your own personal design style to your current property, making sure that it reflects your taste and unique character.

Does the work require planning permission?

Many small scale domestic extension projects don’t require planning permission in Northern Ireland. These types of projects are classified as ‘Permitted Development’. There are a number of criteria that your project will need to adhere to in order to qualify as permitted development. For extensions in Northern Ireland, this means conforming to a certain size, height, position from boundaries etc. More information about permitted development criteria can be found at the following link;

https://www.legislation.gov.uk/nisr/2015/70/made

It is worth checking with your local planning office if you are unsure about how the permitted development rules apply to your specific project. If the project does not fall within permitted development criteria a planning application will be required. In many cases, house extensions in Northern Ireland will only require a Householder Planning application, as opposed to a Full Planning Application.

What other types of Statutory Approval are required?

Typically, the next stage of the house extension project in Northern Ireland is Building Control Approval. Building Control is divided into two main stages; the plans check stage (where Building Control will assess the drawings for compliance with the Building Regulations) and site inspections (where a building control officer will visit your site/property and inspect the work at key stages.) If all the works are compliant then you will receive a Building Control Completion Certificate at the end of the project.

As a client for a house extension project, it’s also important to understand what your obligations are under the CDM (Construction Design and Management) Regulations, with regards to health and safety. At Gilmour Architects we can advise you on what the specific CDM requirements are for your project.

How much will my project cost?

It is critical to understand what the total cost of your extension project will be from the early design stages. At Gilmour Architects, we can offer cost advice, typically based on costs per square meter and using our experience working on similar home extension projects. It is also useful for a Quantity Surveyor to assess the project design from a cost point of view and in doing so they can produce a ‘Budget Cost Plan’, which essentially breaks the overall construction down into its individual elements. A cost is assigned to each element and consequently an accurate overall project cost is provided. Finally, a suitably experienced and reputable builder can also guide you on budget costs at any early stage. As well as construction costs, don’t forget to factor in professional fees (architect, structural engineer, quantity surveyor etc.), council fees (planning and building control) and VAT.

How long will it take?

The length of time a house extension project will take to construct will obviously depend on the complexity and size of the build. In order to save time on site and mitigate against delays, it’s important to ensure that detailed drawings and specifications are produced upfront, prior to any works taking place, to avoid having to make expensive changes on site. Drawings will also be required for any statutory approvals, as previously discussed. We would also strongly recommend entering into a contract with the builder that you choose to carry out the works. The contract will set out terms and conditions that all parties are obliged to adhered to, one of which being a start and end date. The builder should also be able to provide you with a programme of works, so you know how long it will take to complete individual elements of the build and so you can track progress to ensure that the build is on schedule.

Case Study – Downhill Cottage Extension, Castlerock

This quaint thatch cottage on the North Coast required additional living space to make it a more functional home. The entrance was relocated to the side of the property within a new thatched roof addition, leading to a separate and spacious open-plan living/kitchen/dining extension to the rear. Externally, the extension was finished in white render under a natural slate roof, with galvanised steel rainwater goods. This extension project provided much-needed additional space for a growing family, which also reflected their unique style and character.

If you are planning a house extension project, please feel free to contact us to discuss how we can help.

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