Groundworks or excavations are a necessary part of many construction projects. We’ve provided an overview of the health and safety aspects to consider during excavations below but this is no replacement for our full CDM 2015 Guidance on Demolition which is available for download.


The biggest hazard associated with excavations and groundworks is collapse of the sides. This risk is increased when excavations are located close to existing foundations, other excavations or voids.

It is also important to consider other groundworks and excavation hazards including the risk of exposure to potentially harmful contaminants whose levels cannot always be measured by sight or smell.

Avoiding excavations

Designers should consider alternative construction and installation methods to obviate the need to make an excavation on site. See the full CDM 2015 excavation guidance for examples.

Making excavations safer

Designers can also help contractors avoid foreseeable risks. This might be by ensuring you have provided detailed information about the site conditions, for example the proximity of other excavations and foundations.

A detailed site investigation (SI) to determine whether the proposed excavation is hazardous should also be undertaken.

Providing information about the location of utility services, the maximum depth of excavations and groundworks and your design assumptions about load bearing and the location of the plant should also be considered for inclusion.

Download the full guide:


Other useful SID CDM 2015 Guidance:

  • Crane information