Drilling Into an Existing Concrete Slab: What Should You Check First?
Before anyone drills into an existing concrete slab, establish what kind of slab it is and have the proposed work reviewed by the appropriate project professionals. Give them the intended locations, equipment details, and available construction records. A convenient spot on the floor is not, by itself, an approved drilling location.
Start with the building record, not the drill size
For a Middle Tennessee property manager adding equipment or arranging a tenant improvement, the first useful task is assembling a review packet. Include structural drawings, renovation records, installation instructions, and a marked photograph showing the proposed work. Identify the floor level and room so an older drawing cannot be mistaken for the area being changed.
The Post-Tensioning Association's June 2024 guidance identifies construction records, reinforcement drawings, and consultation with the original designer as ways to investigate whether a structure is post-tensioned. It also cautions that drawings and visible clues are not foolproof ways to locate tendons. Cutting an unbonded tendon can release stored energy and remove its tension along its length. This is a reason to arrange specialist review, not to attempt exploratory drilling.
Ask for a clear decision before scheduling installation
Ask who will identify the slab system, who will determine the necessary investigation, and who will approve the proposed attachment or opening. Keep locating work and design review as separate questions: knowing where an embedded item lies does not answer whether the proposed change is appropriate.
Request a marked plan tied to the actual installation. Ask the installer to flag any change in equipment, location, or hole requirements for renewed review instead of treating an earlier decision as permission for a different arrangement. If records are missing, make that an unresolved item in the schedule rather than filling the gap with an assumption.
For the handoff, record the reviewer, the accepted layout, outstanding conditions, and the person responsible for notifying the installer when work may proceed. Keep the resulting records with the building files for future maintenance. Milliken lists floor slabs, parking garage work, and other commercial concrete services; describe the existing structure when requesting a discussion, without assuming that every specialist investigation is included.
Frequently asked questions
Does a small hole eliminate the need to check the slab?
No. Hole size alone does not establish what lies in its path. Have the proposed location and depth considered as part of the project review before installation.
What if the installer needs to move the attachment?
Send the revised location back through the agreed review process. Update the marked plan and communicate the decision before work proceeds at the new spot.