The Fittra website provides an in-depth analysis of the factors that influence the average cost of building a house in the UK. According to their guide, the average cost typically begins at around £1,200 to £1,500 per square meter for standard construction projects. For more luxurious and complex builds, the cost can escalate to £2,500 or more per square meter.

Key Factors Affecting the Average Cost:

1. Location: The cost of building varies significantly depending on the location. In prime areas like London, the expenses for land, labor, and materials are notably higher, leading to an increased overall cost.

2. Size and Type of House: The total cost is also heavily dependent on the size of the house. For example, the average cost of building a 3-bedroom house might range between £126,000 and £300,000, while a 5-bedroom house could cost between £280,000 and £600,000.

3. Design Complexity and Customization: More intricate designs and additional customizations can drive up costs, especially when using premium materials and high-end finishes.

4. Additional Costs: There are other expenses to consider, such as legal fees, planning permissions, and utility connections. If you're considering a kitchen extension, this can also add to the overall budget, depending on the complexity and materials chosen.