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Many people considering an extension may be concerned about the cost which is understandable. However, extensions can actually be a very cost-effective way to create more space in your home which are tailored to your unique needs. Building an extension is certainly more affordable than moving house, particularly in the current climate. You’ll also benefit from fantastic added value to your home with an extension if you do decide to sell, so it’s unlikely you’ll lose out in the long-term.

There are so many benefits to building an extension, it gives you the opportunity to create a design which is bespoke to the features and functions you really want. It’s very rare when you’re searching for a new house that it already has absolutely everything you want and need. This is why building an extension gives you the freedom to design a new space for your unique family to enjoy and the make the most of.

Adding an extension to your home will significantly increase your property value, it will help to make the most of your outdoor space, offer several room choices, and create additional space, all the while tailored to your unique needs. We have an experienced team at Peninsula Group who will not only provide a trusted service but will also offer excellent design ideas and skills to create your family’s dream extension.

Budgeting for an extension

The size of your extension and the quality with finishing touches will vary the price significantly so it’s difficult to give a simple answer. With so many factors to consider such as building walls, laying the foundation, electrics and plumbing, plastering, adding new appliances, painting and decorating, and much more, there are many factors which could alter the cost depending on your preferences.

To give you an example of costs, the average cost for a 20m2 extension is approx. £37,500 which will typically add between 10-20% onto your home’s value (Checkatrade, 2022). The cost of an extension varies widely from a garage conversion estimated at £7,500 to a basement extension for £160,000. There’s such a huge range of options available, you can build above, below, or to the side and behind your property.

Figures from My Build Estimate who are a renowned estimating company monitored by the Royal Institution of Chartered Surveyors (RICS) indicate the costs based on square meterage. They estimate the below:

  • Basic extension average cost (20m2) = £37,500
  • Standard small extension average cost (20m2) = £37,500
  • Standard medium extension average cost (30m2) = £52,500
  • Standard large extension average cost (50m2) = £87,500
  • Premium extension average cost (30m2) = £76,500

Included within these prices are the essential build elements such as constructing the foundation, building the walls, insulating the structure, adding plasterboard, adding any subfloors, and making a basic provision for the plumbing and electrics. Approximate costs from estimating companies like the above, generally won’t include any decoration, appliances, or finishing touches. These are of course estimated averages. Our expert team at Peninsula Group will be able to discuss your requirements in more detail and provide an accurate quote for your extension.

An important factor you need to consider are how many storeys you want to build, whether your requirements could fit into a single storey or if you’d benefit from a double storey extension. Other factors to consider are the quality of your build, how involved you’ll be in the project, the shape and size of your extension, whether you’re adding a kitchen or bathroom which will require plumbing and electrics, and the amount of glazing you’d like for your extension. Outside of these estimated costs, you may also need to factor in the cost of any building regulations applications, party wall agreement (if your extension affects your neighbour’s property), planning permission, surveys and insurance, architect and structural engineer fees, and a lawful development certificate.

Other changes which could affect the cost of your extension include the location of your home, ease of access, groundworks, and clearing the space. You could potentially save some money by doing some preparation work for your architect so that you have a clearer idea of what you’d like before you start your billable hours with them. You could also submit the planning permission application yourself to save on fees when using an expert to do this for you. Of course, you’ll need to do your own research which can some time but will save you money in the long-term. One of the most expensive aspects of planning permission is objections from neighbours so speaking to them ahead of time is a great idea to save yourself the stress and money of having to change anything further down the line.

Are you ready to start your extension build?

Your extension will go through various stages of building, typically beginning with the initial design where most people utilise the services of an architect. Once you’ve agreed on the design for your extension, you will need to seek out planning permission from your local authority if this is required. One of the first build stages is to prepare the site and dig out the foundations to ensure the extension is built safely to the correct building regulations. During this groundworks phase, you may have to move drains or tree roots which can create a challenge with increased costs.

Once the groundworks have completed, the building of the main structure will begin with either a timber or brick frame. This is the stage where the roof is built, and the extension is made into a watertight structure by adding plasterboard and subfloors. Adding the fittings usually comes next such as electrical sockets, radiators, windows, and doors. Finally, you can add the finishing touches to your extension making sure that it’s a true extension of your home.

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