Trial Pits & Boreholes
Hand-dug trial pits and boreholes to BS 5930: foundations exposed and measured, shear vane testing, logged strata and scaled section drawings for engineers and building control.
A trial pit is the most direct answer to the question every structural engineer eventually asks: what is this building actually standing on? We excavate carefully against the structure, expose and measure the foundation, log the strata, and put it all into a scaled drawing your engineer can design from - reported to BS 5930.
Where the question continues below the base of the pit, we form hand-auger boreholes and take shear vane readings in the virgin stratum, so the report records not just what the ground is, but how strong it is where it matters.
From the ground, into the report
Every pit is photographed through the works and issued as a measured section drawing - the same evidence trail below is taken from a real issued investigation.
When trial pits are the right tool
- Subsidence investigations: exposing the foundation and the ground it bears on, alongside a CCTV drain survey where leaking drains are the suspect.
- Extensions and structural alterations: confirming foundation depth and form before your engineer sizes the new loads.
- Soakaway and drainage design: proving the strata alongside BRE365 percolation testing.
- Party-wall and pre-works evidence: a measured record of what exists before anything changes.
Get the ground on paper.
Call Clever Works on 01252 214 098 or request a fixed quote - tell us what your engineer needs to see and we will scope the pits to suit.
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Frequently Asked Questions
How deep is a trial pit?
Typically to just below the underside of the foundation, with a hand-auger borehole continuing below the base where the strata or the engineer's question requires it. Depth is agreed in the scope before we dig.
Will you make good afterwards?
Yes - pits are backfilled in layers and the surface reinstated. We photograph before, during and after, so the record shows the site as found and as left.
Do you work in occupied homes and gardens?
Yes, most of our investigations are at occupied properties. Pits are hand-dug, protected while open and never left open overnight without covers and barriers.
What do I actually receive?
A BS 5930 report: scaled section drawings of each pit, logged strata, shear vane readings where taken, and photographs at every stage - the format structural engineers, insurers and building control expect.