The Construction Design and Management Regulations (commonly known as the CDM Regulations) were re-introduced in April 2007 after initial introduction in 1994. The revised Regulations are intended to make it easier for those involved in construction projects to comply with their health and safety duties. The risks involved in underpinning are identified and managed in accordance with CDM legislation.
Most types of underpinning involve digging holes under buildings in confined spaces. The existing structure is expected to defy gravity and temporarily arch over the excavation. Collapses can occur. The safety issues that have to consider:
- Investigate services before digging
- Check that underpinning pits cannot flood or be gassed
- Strengthen superstructure before digging
- Check that walls above are strong enough to support themselves over pits
- Support sides of excavations
- Ensure that workers can escape from pits easily
- Use threaded couplers instead of dowel bars to connect reinforcement rods between sections of shallow mass concrete underpinning
- Ensure safe access and ventilation to pits
- Use a Banksman to oversee safety.