What is the cost in 2026 for building extensions in Southampton?

The cost in 2026 for building extensions in Southampton varies significantly based on the type and size of the extension. For a simple single-storey extension, you can expect to pay around £1,500–£2,200 per square metre. This means a typical 20 square metre extension could range from £30,000 to £44,000. If you're considering a loft conversion, prices are typically between £30,000 and £50,000, depending on the complexity and materials used, while a garage conversion might cost you around £10,000 to £25,000.

It's essential to work with certified professionals, such as those registered with NICEIC for electrical work or Gas Safe for any gas installations, ensuring safety and compliance with local regulations. Additionally, Southampton has specific planning regulations that may influence costs and project timelines, so it’s wise to consult with local authorities or a knowledgeable builder.

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