Do I need a site investigation before building?

A site investigation is strongly recommended for all new buildings and is effectively mandatory for Building Regulations approval of foundation design. A typical investigation includes: desk study (geological maps, historical land use, mining records); trial pits or boreholes (minimum 2–3 for a house, to 3–4 m depth); soil classification and bearing capacity testing; groundwater level assessment; chemical analysis (sulfate, pH — affects concrete specification); and tree survey (for clay sites).

A site investigation is strongly recommended for all new buildings and is effectively mandatory for Building Regulations approval of foundation design. A typical investigation includes: desk study (geological maps, historical land use, mining records); trial pits or boreholes (minimum 2–3 for a house, to 3–4 m depth); soil classification and bearing capacity testing; groundwater level assessment; chemical analysis (sulfate, pH — affects concrete specification); and tree survey (for clay sites). Cost: £1,500–3,000 for a domestic site. This investment prevents foundation failures that can cost £20,000–100,000+ to remediate.

Why this matters

This question relates to Timber Home Foundations: Screw Piles, Raft & Strip Options, which covers the broader topic in detail. Understanding this specific aspect helps architects, builders, and timber dealers make informed specification decisions.

For full context and additional technical detail, see our comprehensive guide:

→ Timber Home Foundations: Screw Piles, Raft & Strip Options

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About this answer

This answer is part of the PuurModulair Knowledge Base — comprehensive timber specification guidance for architects, builders, and dealers across the UK, EU, and Scandinavia.