Concrete drilling or cutting: what information is needed beforehand?

Describe the purpose of the opening

An opening for ventilation, a pipe route and a stair opening have different requirements. Explain what the opening is for and include dimensions from the relevant installer or designer. An appliance's measured external dimensions do not automatically determine the required drill size.

State which details are still unknown. An estimated floor thickness can provide a useful initial indication, as long as it is clear that it has not been confirmed. Do not have a floor or wall drilled simply to find its thickness without first investigating it.

Enquiry checklist

Preparation also covers the rear and underside

The space beneath a floor opening or behind a wall may become a working and safety zone. Discuss how access will be provided and who will inform the occupants. For a stairwell opening, the plan must also include safe guarding after cutting.

Pipes and reinforcement require separate attention. Available drawings and, where necessary, further investigation support the assessment. Deciding whether to use a scan or another type of investigation, and interpreting the results, are part of expert preparation.

Ask about water, slurry and concrete pieces

Make sure the quotation specifies how dust or cutting water will be controlled and who will remove the material and slurry. Cutting an opening and transporting the removed sections out of the building are separate tasks. Support and lifting arrangements must suit the project; there is no single safe approach for every opening.

Agree the finished opening dimensions and finish with the next contractor before work starts. The cutting crew can work to the same requirements only when the necessary drawings and agreements are available.