How Much Will my Foundations Cost?

Foundations of a house
(Image credit: David Snell)

Foundations are the one element of a construction project that it is impossible to fully plan out until you start on site. Ground conditions and requirements vary, and problems may not be apparent until you break ground, meaning budgeting this section of your build will be, at best, general.

Most builders quote, without further information or instruction, on the basis of what is known as a deep strip foundation. This assumes a trench 600mm wide and 1,200mm deep for all external walls, and internal load-bearing walls with a minimum 225mm of concrete tamped level.

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Deep strip foundations
Excavate 30m³£812.80
Bulked up to 45m³ loaded into lorries£685.19
Soil disposal incl tipping charges£1,125.00
Reinforcement mesh£192.00
Concrete foundations 10m³£1,339.45
Total£4,154.44
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Trenchfill foundations
Excavate 30m³£812.80
Bulked up 45m³ loaded into lorries£685.19
Soil disposal incl tipping charges£1,125.00
Reinforcement mesh£384.00
Concrete foundations 25m³£3,349.64
Total£6,356.63
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2m-deep trenchfill foundations
Excavate 50m³£1,500.00
Bulked up 75m³ loaded into lorries£1,141.99
Soil disposal incl tipping charges£1,875.00
Compressible material, slip membrane and positioning£606.00
Reinforcement mesh£408.00
Concrete foundations 45m³£6,029.35
Total£11,560.34
David Snell

David is one of the UK's leading self build and plotfinding experts, and a serial self builder who has been building homes for 50 years. The author of Building Your Own Home, David spent decades as a speaker and expert at self build exhibitions such as the Homebuilding & Renovating Show. He has recently finished his fourteenth self build project.