Down Street Mews, Central London

January – April 2015

We drilled 12 x 174m ground loops for the geothermal heating of a domestic property. Initially, the boreholes were to be drilled from ground level in a courtyard, with a 6-week schedule using a sonic rig for speed. However, due to changes in the construction programme, the boreholes had to be drilled in a basement 5m below ground level, within a 20m x 10m area, constrained by an access ramp, a tower crane, and horizontal steel beams supporting the basement walls, limiting headroom.

The sonic rig was unsuitable due to its size, so we used a conventional rotary rig with a shortened mast. We successfully drilled to 174m, installed ground loops, and cased off to the Chalk bedrock at 90m within 3 to 4 days per borehole. Despite basement flooding and the need to replace the piling mat, we completed the project in 12 weeks.