Concrete scanning before drilling is used to investigate what may be inside a concrete wall, slab or other element before drilling begins. Depending on the scanning technology and material, detection systems can help locate reinforcement, metal, wires, pipes and other embedded objects. Scanning does not remove every drilling risk or guarantee that an opening is safe, so the results should be considered together with drawings, site information and appropriate project decisions.
- Why Scan Concrete Before Drilling?
- What Can Concrete Scanning Find?
- Why Does Reinforcement Matter?
- Why Look for Embedded Services?
- How Does Concrete Scanning Work?
- What Can Scanning Not Tell You?
- What Happens Before Drilling?
- When Should Concrete Be Scanned?
- Is Scanning Needed for Every Core Hole?
- Concrete Scanning FAQs
Drilling into concrete without understanding what is behind the surface can create avoidable problems. Reinforcing steel, electrical conductors, pipes and other embedded objects may not be visible from the outside. A scanner can provide additional information before the core drill reaches the concrete.
This is particularly relevant when an opening must be placed through an existing wall or slab. Existing drawings may help, but the actual structure can differ from old documentation. Scanning provides another source of information that can be used during planning.
Why Scan Concrete Before Drilling?
The main purpose is to understand the internal conditions around the proposed drilling location. A scan can help identify embedded objects and reinforcement so the drilling position can be reviewed before work begins.
Hilti's current wall-scanning equipment, for example, is designed to locate embedded objects for drilling, coring and cutting. Depending on material and depth, its sensors can identify items such as rebar, live wires, metal and plastic pipes.
Reinforcement
Identify reinforcement that may be present around the proposed drilling position.
Embedded Services
Look for concealed wires, pipes and other detectable objects before the bit enters the concrete.
Planning
Use scan information with drawings and site knowledge when confirming the drilling location.
What Can Concrete Scanning Find?
The answer depends on the scanner, sensing technology, material, depth and object being investigated. Different technologies have different capabilities, so a scan should never be described as detecting every object inside concrete.
Reinforcing Steel
Reinforcing bars can often be located using suitable concrete-scanning equipment. Some systems can also estimate information such as rebar cover and size within their specified operating range. Hilti describes electromagnetic induction and pulse-radar technologies for locating reinforcement and other embedded items.
Electrical Conductors
Some scanners can detect live wires or other electrical-related objects. Detection capability depends on the sensor and the specific site conditions, so existing electrical information should still be considered.
Pipes and Other Embedded Objects
Some scanning systems can identify metallic and non-metallic embedded objects. Hilti's PS 85, for example, lists applications for locating rebar, live wires, metal and plastic pipes in suitable wall materials.
Why Does Reinforcement Matter?
Reinforcement is part of the structural system in reinforced-concrete elements. If a proposed core hole intersects reinforcement, the project team may need to reconsider the position or determine the appropriate engineering approach.
Scanning can help identify reinforcement around a proposed location before drilling. A Hilti structural handbook describes scanning methods for identifying reinforcement and other embedded items before boreholes are drilled. It also notes that drilling decisions can be important to structural performance in relevant applications.
Important: A scan is an investigation tool, not a substitute for structural design or project approval. Where a proposed opening could affect a structural element, the responsible engineer or project authority should determine the acceptable location and method.
Why Look for Embedded Services?
Existing buildings can contain services inside walls, slabs and other construction elements. A planned MEP opening may be close to an older installation that is not shown clearly on current drawings.
Identifying detectable services before drilling can help the team reconsider the opening location before the tool reaches them. This is especially relevant when drilling through an existing structure during renovation, fit-out or building-services modifications.
The broader principle is simple: information about concealed services should be obtained before intrusive work wherever the project conditions make those services reasonably possible.
How Does Concrete Scanning Work?
Concrete scanning uses sensing technology to investigate the material below the surface. Two important approaches include electromagnetic induction and pulse radar.
Electromagnetic Induction
Electromagnetic systems are commonly used for locating ferrous reinforcement and can provide information about rebar position and cover within their operating limits.
Ground-Penetrating Radar
Ground-penetrating radar can investigate a broader range of embedded materials. Hilti's structural guidance describes pulse-radar technology as capable of detecting ferrous and non-ferrous embedded items, including some metals, post-tensioning systems, wires, wood and cavities.
The scanner is moved across the area being investigated, and the resulting measurements are interpreted to identify potential objects and their locations. Scan depth and accuracy depend on the equipment, material and object being detected.
What Can Scanning Not Tell You?
Scanning is valuable, but it has limits. A scan should not be presented as a guarantee that no hidden hazard exists.
- Detection depends on technology: Different sensors identify different materials and object types.
- Depth matters: Detection capability decreases or changes according to material, object and scanner specifications.
- Interpretation matters: Scan results need to be understood correctly before drilling decisions are made.
- Drawings still matter: Existing structural and MEP information should be reviewed alongside the scan.
- Structural judgment may still be required: Scanning does not determine whether a proposed hole is structurally acceptable.
This distinction is important because scanning reduces uncertainty; it does not eliminate it.
What Happens Before Drilling?
A practical workflow combines information from the project with the scan itself.
1. Confirm the Proposed Opening
Establish the required diameter, depth and location from the latest drawings or project instructions.
2. Review Existing Information
Check available structural drawings, MEP drawings and previous project information before scanning.
3. Scan the Area
Use an appropriate scanner and investigate the proposed drilling zone and surrounding area needed to interpret the results.
4. Interpret the Results
Identify detectable reinforcement or embedded objects that could affect the proposed drilling point.
5. Review the Location
If the scan indicates an object where the opening is planned, the position should be reconsidered according to project requirements.
6. Drill Using the Approved Method
Once the location and drilling approach have been established, select compatible equipment and carry out the work under the project's required controls.
When Should Concrete Be Scanned?
The need for scanning depends on the structure, available documentation, proposed work and project requirements. It can be particularly relevant when drilling or cutting existing concrete where concealed reinforcement or services may be present.
Common situations include new MEP penetrations, renovation work, core drilling through slabs or walls, and modifications to existing buildings.
Our guide on core cutting for MEP openings explains how service requirements affect the planning of concrete penetrations.
Is Scanning Needed for Every Core Hole?
There is no single answer for every project. The need depends on the concrete element, the proposed opening, known embedded services, available drawings and the requirements set by the responsible project team.
A small non-structural opening in a well-documented location may present different planning considerations from a large penetration through an existing structural slab. The decision should therefore be based on the actual work rather than a blanket rule.
Where scanning is appropriate, it should be treated as one part of the pre-drilling assessment rather than the entire assessment.
Plan the opening before choosing the tool
See Core Cutting for MEP Openings for service penetrations, or Wet vs Dry Core Drilling for drilling-method considerations.
Concrete Scanning FAQs
Why scan concrete before drilling?
Scanning can help identify reinforcement and detectable embedded objects before drilling, giving the project team additional information about the proposed opening location.
Can concrete scanning find rebar?
Suitable scanning systems can locate reinforcement. The detection range and information available depend on the scanner, technology, concrete and reinforcement conditions.
Can a concrete scanner find electrical wires?
Some scanners are designed to detect live wires or electrical-related objects, but detection depends on the equipment and site conditions.
Can concrete scanning find pipes?
Some scanning systems can detect metallic and certain non-metallic pipes. The actual capability depends on the sensor, material, depth and object characteristics.
Does concrete scanning guarantee safe drilling?
No. Scanning provides information about detectable objects, but it does not eliminate every risk or replace drawings, engineering decisions and appropriate site controls.
What technology is used for concrete scanning?
Technologies include electromagnetic induction and pulse radar. Different systems have different detection capabilities and operating ranges.
Should concrete be scanned before MEP drilling?
Scanning may be appropriate when reinforcement or concealed services could affect the proposed penetration. The project team should determine the required pre-drilling checks.
What should happen after concrete scanning?
The scan results should be interpreted and reviewed with the available project information before the drilling position and method are finalized.