Mini Digger for Extension Footings

Footings for a domestic extension typically need to reach below the frost line and onto suitable bearing ground, which in the UK usually means a minimum depth of around 1 metre, though your building control officer will confirm the exact depth required for your soil type.

Why depth and access both matter here

A 0.6 tonne micro digger, with a dig depth of around 1.2 metres, covers most standard footing depths and is narrow enough to work close to an existing building without damaging it. Where footings need to go deeper, such as on clay soil or where building control specifies extra depth, a 1.0 to 1.2 tonne mini digger reaching around 1.8 metres gives more room to work with.

Working close to an existing structure

Extension footings almost always mean working within touching distance of the existing house, so a compact machine with good visibility and precise bucket control matters more here than raw power. Trench sides also need to stay square and clean for building control inspection, which favours a smooth-edged trenching bucket over a toothed one.

• Confirm required footing depth with building control before digging
• Check for existing services running close to the house before starting

Browse our full mini digger range to compare dig depths, or see our foundations groundworks guide for related work.