The short answer is that it is a layer of materials which is constructed over other materials. In remediation, we use them to remove a pathway from contaminated strata to receptors. If the contaminant does not have a pathway to a receptor then it is therefore no longer a risk to that receptor. Capping layers come in many forms from shallow soils in a rear garden of a residential property through to major earthworks involving 100,000’s of tonnes of capping materials as shown below.
This picture above shows a great example of an earthworks cap, the ground has been prepared to avoid any puncturing of the geo-membrane, a layer of fine grained material has been laid across the membrane to avoid puncturing the membrane, and finally a coarse grained cap is laid, on which construction works can start.
Capping layers can have the additional benefit of being installed to improve the ground conditions for construction purposes.
Soil remediation guide
Approaching soil remediation without any prior knowledge can be difficult and uncomfortable at times, especially when it can potentially be very costly. This free eBook will help you understand the whats, the whys and the hows of soil remediation in the simplest terms.