Piling Contractors in Southampton and Hampshire

Signal Box Farm is a rural site in Burghclere, near Newbury, beside a historic signal box. The ground investigation found alternating bands of clay and sand down to 18m, so the new house needed piles. We drove 36 steel cased mini-piles at 220mm diameter with a 0.5-tonne hammer. Loads ran from 50kN to 140kN depending on position. Each pile carried a 2H16 rebar cage and each was set-tested to confirm its bearing capacity.

We then built the raft slab on top: 164.5m² at 250mm thick, in C28/35 concrete with A393 mesh top and bottom. Beneath it went 160mm Cellcore HX-S void formers to guard against clay heave, with timber edge formwork and a brick edge toe detail. Mobilisation, piling and the slab pour took 12 days.

At The Old Vicarage in Greywell, near Hook, an oak-framed garden building replaced an older one. Six Type 76R screw piles with triple helix lead flights were torqued into the chalk. The helices measure 200mm, 250mm and 300mm across. Safe working loads ran from 50kN to 100kN, and the achieved factor of safety was 4.1 against a required minimum of 2.5. A 28m² raft slab, 175mm thick on 50mm blinding, completed the foundation in about four days.

What we say here about Hampshire ground comes from the two jobs written up above, so it is a record of those sites and not a survey of the county. At Burghclere the investigation showed made ground over layered clay and sand, with the bands alternating to 18m depth. At Greywell the pile design was based on gravel with flints over chalk, using an effective soil density of 18kN/m³ and a friction angle of 30°.

Screw piles suited the Greywell profile because they gain capacity from end bearing and from shaft friction in granular soil. Your site may match neither job. A ground investigation report tells the engineer what is there. If you have no report, send what you do have and we will advise on the next step.