Window Sampling — also known as Dynamic Sampling, Mini Boreholes, or Windowless Sampling — is a versatile site investigation technique used for geotechnical and environmental assessment. It is specifically designed for soft ground and cohesive strata, where steel sample tubes are driven into the soil to recover clean, minimally disturbed samples of clay, sand or silt for laboratory analysis.
This method offers a cost-effective and efficient solution for shallow to medium-depth investigations, typically between 2 and 6 metres, and up to 10 metres in favourable ground conditions. Window sampling provides reliable subsurface profiles that help identify soil properties, assess contamination, and inform design decisions for new developments.
Because the equipment is lightweight and compact, window sampling is ideal for restricted-access sites, gardens, basements, narrow passages, sensitive environments and areas close to structures.
Window Sampling results are often used to support:
Window Sampling involves driving cylindrical steel tubes into the ground using a percussive or hydraulic hammer. The soil is pushed into the tube and removed as an undisturbed sample for logging or laboratory testing.
Key features of the technique:
Window sampling rigs are available in several formats:
This flexibility makes window sampling suitable for a wide variety of investigation scenarios.
Windowless sampling uses sealed plastic liners instead of open-window tubes. Liners protect the integrity of the sample and prevent cross-contamination, making them ideal for:
Both window and windowless methods provide reliable samples for our engineers to log in accordance with:
Our track-mounted and portable rigs are also capable of carrying out a range of in-situ tests and follow-on monitoring
installations, including:
These additional tools allow Phase Ground Investigations to obtain a comprehensive picture of the site’s ground conditions.
Window sampling is the go-to technique where access is limited, ground is soft, or disturbance must be kept to a minimum. It is widely used for residential, commercial and environmental projects.
Common applications include:
Because the rig is compact and lightweight, it can be used:
Before starting any investigation, Phase Ground Investigations undertakes:
We ensure the investigation technique is appropriate for the site conditions and project requirements.
Our team includes experienced:
We manage the process from design and drilling to logging, sampling, monitoring and final reporting.
For reinforced accuracy and compliance, all work follows current standards and Eurocodes, ensuring high-quality results that support planning submissions and design development.
Both techniques are available as part of our ground investigation services across the UK.
If you’re planning a development, assessing a brownfield site, or concerned about radon levels in an existing property, we’re here to help.