What is the cost of a house extension near me local building Harrow?

The cost of a house extension in Harrow typically ranges from £1,200 to £2,000 per square metre in 2026, depending on factors like design complexity, materials used, and local construction rates. For an average-sized extension of 20 square metres, you might expect to pay between £24,000 and £40,000. It's important to use certified professionals, such as those registered with the Federation of Master Builders (FMB) or the National Federation of Builders (NFB), to ensure quality workmanship and compliance with local building regulations. Additionally, if your extension affects gas lines or heating systems, make sure to involve professionals who are registered with Gas Safe to avoid safety hazards. Always consider obtaining multiple quotes from local builders to ensure you get a fair deal.

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