How much does it cost to enlarge your house with AKENA?

Adding an extension is an attractive idea for gaining space, improving comfort and increasing the value of your property. However, this approach requires careful financial planning. It is best to be well prepared to avoid unpleasant surprises and ensure that the project runs smoothly. Would you like to estimate the price of enlarging your house? Steps, factors, specifics, costs, financing: AKENA tells you everything you need to know to evaluate the budget necessary for the enlargement of your living space!

Calculating the budget required for the construction of an extension to the house is essential in planning your enlargement project. To do this, we advise you to proceed in stages.

First and foremost, it is essential to clearly define your project. The type of extension, the planned surface area and the choice of materials have a direct impact on the final cost. This stage therefore allows you to clarify your expectations and facilitate communication with the professionals you consult.

Whether it's to welcome a new member of the family, to benefit from a workspace at home, or to have a place dedicated to your evenings with friends, we recommend that you determine:

the room you want to design and its purpose (a bedroom, a dining room, an outdoor relaxation area, an open kitchen, etc.);
the special features required for this room (access to the garden, lighting, thermal or sound insulation, etc.);
the surface area required for your project according to your needs.

Akena Véranda - Extension - Agrandir sa maison

Don't forget your outdoor space either! Adding an extension can affect the layout of your garden. It is therefore essential to adjust your plan accordingly, whether it be to create an adjoining terrace, build a path or integrate the structure into the landscape with the rest of the property.

Consulting experts is essential to obtain an accurate estimate of the price for enlarging your house. They can provide you with recommendations based on the specifics of your project and regulatory or technical constraints.

At AKENA, specialists in extensions for over 40 years, our advisors are at your disposal to answer all your questions, guide you in your choices and send you a detailed quotation.

In addition to the cost of the extension itself, the price of enlarging your house includes certain additional costs such as:

Applying for planning permission: before starting work, it is often necessary to apply for planning permission from your town hall. This document certifies that your project complies with current planning regulations. It generally costs between €500 and €1,500. This includes the application fee and, in some cases, the fee for an architect or designer to prepare the required plans and documents.
Insurance: taking out certain types of insurance is compulsory to protect yourself against potential damage or accidents. The main one is structural damage insurance. In the event of recognised faulty workmanship after the work has been completed, it allows you to carry out the necessary repairs without waiting for a court to decide who is responsible. The cost varies depending on the total amount of the work. At AKENA, all our products come with a 10-year warranty!
Masonry work: before starting the enlargement of your house, it is possible that some work may need to be carried out (preparing the land, foundations, reinforcing the building, etc.).

Good to know: if your property is in a protected or heritage area, the design of an extension requires compliance with specific regulations to preserve the aesthetics and character of the location. This may mean using specific materials or designs, which often increases the price. The procedures for obtaining the necessary permit include the preparation of impact reports and additional studies, which can cost between €1,000 and €2,500.

Akena Véranda - Loft - Baies ouvertes vitrées

Allow for contingencies

When planning the finances of your extension project, it is wise to include a safety margin to cover unforeseen expenses.

Construction work, even the best organised, can encounter unexpected obstacles such as discoveries on site that require additional operations. By allocating a margin of 10 to 20% of the total budget, you give yourself the flexibility to manage these contingencies without compromising the quality or completion of your plans.

Evaluate the available assistance

The State and many regions offer subsidies, financial aid or tax credits to encourage energy renovations or the use of ecological materials. This can help you reduce the cost of enlarging your house.

For example, if your extension project includes improving the performance of your home so that it consumes less energy, you may be eligible for specific grants. It is therefore important to check with the local authorities or your AKENA advisor to identify the programmes applicable to your situation.

Estimate the overall budget

Once you have all the information mentioned above, compile it to estimate the overall budget for your extension project.

Include the cost of the construction itself, the associated costs and a margin for unforeseen events. Don't forget to subtract any financial assistance for which you are eligible. This estimate will give you a clear idea of the total amount needed to start the enlargement of your home.

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The cost of enlarging your house with an extension can be influenced by many factors. Here are the main factors that have an impact on the necessary budget.

This is one of the most obvious factors when evaluating costs. The larger the extension, the more materials and labour it requires. Therefore, the price of enlarging one's house automatically increases in relation to the desired surface area. The latter is often calculated per square metre, but many other factors can affect the final amount.

The choice of building materials greatly influences both the initial price and the future costs associated with the maintenance and durability of your home extension. Opting for materials that offer good value for money is essential to guarantee the solidity of the structure, its resistance to bad weather, and to minimise the need for renovation or repair in the long term.

For example, high-quality materials such as aluminium may require a larger investment at the time of purchase. However, their robustness and low maintenance requirements make them an economical option over several years. Conversely, less expensive solutions may require regular maintenance, increasing expenses over time.

The design of the roof can have an impact on the price of enlarging your house. It can be flat, sloping, vegetated, have a skylight, or feature various decorations. At AKENA, we even offer flat roofs with innovative thermal performance. Each option has its own implications in terms of cost, insulation and aesthetics.

Akena - Extension maison cuisine toit plat - Aluminium

The layout of the space and the equipment

Adding options can quickly increase the price of an enlargement. For example, you can opt for:

special finishes (on the cornices, the front or the roof);
lighting systems;
closing solutions (roller shutters, adjustable sunbreakers, screen blinds, etc.);
comfort equipment (heating, electrical installation, insulation, energy performance, etc.).

Each piece of equipment can add comfort to your extension, but can also increase its initial cost.

The complexity of the project

Extension projects involving delicate architectural forms, complex site constraints, or the need to preserve certain existing elements can result in additional costs. Indeed, an easily accessible area simplifies logistics and reduces costs, as it facilitates the transport of materials and labour. Conversely, complicated access to the site can lead to higher prices.

The difficulty of carrying out operations concerning connection to existing systems (electricity, plumbing, heating) must also be considered in the price of enlarging one's house.

The preliminary work

Even before construction begins, some preliminary work may be necessary, such as:

soil studies;
excavation or drainage operations;
reinforcement of the main building;
masonry work;
felling of obstructing trees;
demolition of existing structures.

These preparatory works can have a significant impact on the overall budget, so they should be considered.

As mentioned previously, the price of enlarging your house depends on the surface area of the extension. Here is a table showing the average costs according to size (for a product made in France, including labour and professional installation):

Surface area of the house extension (in m²)	Average price (in euros, including VAT)
10m²	between €9,000 and €32,000
20m²	between €18,000 and €40,000
30m²	between €27,500 and €50,000
40m²	between €37,000 and €63,000
50m²	between €45,000 and €90,000
60m²	between €50,000 and over €100,000

The other factors cause the different averages to fluctuate. However, these prices are still estimates: the best way to evaluate the amount for your future structure is to request a detailed quotation from professionals in the sector such as AKENA!

Aluminium is a popular choice for house extensions because of its many advantages. It is not only light and strong, but also offers great durability and requires minimal maintenance.

At AKENA, we make it a point of honour to use high-quality aluminium, which gives us the opportunity to offer you a wide range of finishes and customisations. You can choose from a range of colours and textures, allowing you to adapt the design of the structure to the aesthetic of your home. Aluminium can even be combined with wood finishes to bring a warm touch to the exterior of your new living space.

The price of enlarging your house with an aluminium extension is generally between €2,000 and €3,000 per square metre. This price may include the aluminium structure, the glazing and the basic finishes. However, additional options such as integrated heating systems, lighting or automatic blinds may influence the final cost.

Building an outdoor structure such as a pergola attached to your home is an excellent way to expand your living space while enjoying the outdoors.

As well as providing a new place to relax and entertain friends, it can also increase the value of your property by giving it extra character and a larger surface area. Bioclimatic pergolas even allow you to naturally regulate the temperature of the area they cover, while protecting you from the sun and bad weather thanks to adjustable roof slats!

The prices for enlarging your house with a pergola vary widely depending on the materials chosen, the technology, the size of the structure and the complexity of the design. Allow between €500 and €1,000 per square metre for the construction of this type of extension.

Use personal input

Even if it is not always possible to invest a lot of money at once, using your personal savings to finance part or all of your enlargement project is the simplest and least expensive solution. You avoid or considerably reduce the need for external borrowing, which means that you will have no, or less, interest to pay over time.

Apply for a works loan

The works loan is specifically designed to finance projects to renovate or enlarge your home, such as adding an extra room. This type of loan can be an advantageous option for realising your improvement plans without dipping into your savings. It can be for up to €75,000, and is repayable over an average period of 7 years. You can also apply for a mortgage loan to release larger funds.

Several grants may be available to help you enlarge your house, particularly if your project aims to improve the energy efficiency of your home. These may come from the State, local authorities, or various organisations dedicated to the promotion of clean energy. It is important to find out about these opportunities, as they can cover a significant part of the price needed to extend the surface area of your home.

Not sure which solution to go for? Book an appointment with an AKENA technical advisor for a personalised study of your situation. They will guide you in choosing the most advantageous financing for you!

Are you planning to add an extra room to your house? With AKENA, enlarge the surface area of your home with tailor-made solutions, designed to meet your specific needs and suit your budget.

We offer a range of high-quality models and products, designed to guarantee durability and longevity, thus ensuring a long-lasting investment. Our team of qualified professionals will support you at every stage of the project, from design to completion, to make your experience as smooth and enjoyable as possible.

Request a free, no-obligation quotation to transform your home and outdoor spaces, and discover a new dimension of comfort and style tailored to your lifestyle.