Window sampling.

A tube, a liner, a core of soil.

A hollow steel sample tube, usually a metre long, is driven into the ground. A plastic liner inside the tube holds the soil. The tube is pulled out, the liner is cut open, and the soil is logged and sampled. The next tube goes down the same hole, and the diameter steps down as the hole gets deeper.

"Window" samplers have a slot cut in the tube, while "windowless" samplers use the liner instead. The two terms are often used for the same job.

Window sampling is a shallow method. Typical holes reach around 6m, sometimes more in suitable ground, and the tube can refuse on obstructions or very dense ground.

Back gardens and basements.

Window sampling is ideal where there is not room for a larger rig: back gardens, side passages, inside buildings and on embankments. On some sites access is too restricted even for our compact rig, and there we use a hand-held window sampling system that recovers samples in the same tubes.

The holes are small and are backfilled when finished, or fitted with a monitoring well if gas or groundwater needs to be monitored.

When window sampling is right.

• House extensions and new homes on typical soils, where foundations are shallow.
• Sites with tight access or where disturbance needs to be kept to a minimum.
• Contamination sampling across a site.
• Installing shallow gas and groundwater monitoring wells.
• Alongside trial pits, and with dynamic probing to extend information below the sample depth.