What ground investigation do you need before you build?

A ground investigation tells you what is beneath a site before you commit a design to it: the soil and rock profile, the groundwater, the strength and stiffness of the ground, and whether it is contaminated. That information drives foundation and pavement design, earthworks, drainage and any remediation, and it is routinely needed to discharge planning conditions. Put simply, it turns the unknowns that stall and overrun projects into facts you can design and price against.

When you need one

• Before designing foundations or piling for a new building or structure.
• To support a planning application or discharge a planning condition.
• On brownfield or former industrial land, to assess contamination.
• For highways, drainage, earthworks and utility schemes.
• Any time the ground is uncertain and carries design or programme risk.

Who designs it, who delivers it

The scheme itself - how many holes, how deep, what testing - is designed by a geotechnical or geo-environmental consultant to suit what you are building and the risks in the ground. We are the contractor who delivers that fieldwork: getting to the specified depths, recovering good-quality samples and carrying out the in-situ tests. If you do not yet have a consultant engaged, we can point you in the right direction.

What a scheme usually involves

• Intrusive holes - window sampling for shallow soils and made ground, and rotary drilling where the scheme needs rock coring or depth.
• In-situ testing - Standard Penetration Tests (SPT), Dynamic Probe Tests (DPT) and undisturbed U100/U70 sampling to measure the ground in place.
• Sampling - soil, gas and groundwater samples recovered for your laboratory scheduling.
• Monitoring installations - gas and groundwater standpipes, from 19/25mm piezometers to 50/63mm wells, for a period of monitoring after drilling.

How deep, how many holes?

That is set by the design - the size and loading of the structure, the ground model and the risks being investigated. Our job is to reach those depths efficiently and recover good samples whatever the method: shallow soils by window sampling (5-8m, dependant on strata) and deeper or rock holes by rotary, coring in the order of 200m and drilling open holes past 300m where a scheme calls for it.

Getting started

If the investigation is already designed, send us the scope or the tender documents and we will quote it. If you are earlier than that, tell us about the site and what you intend to build and we will talk it through - including whether you will need a consultant to design the scheme first.