ScanAxis · Quebec
Radiant floor heating and heating cables
Drilling a heated slab is not drilling an ordinary one. Radiant floor heating may run liquid through pipes, or rely on an electric cable embedded in the screed, and the two are neither located the same way nor equally forgiving when struck. This page is an entry point on those distinctions and links to the pages that develop them.
Request a quoteTwo families of embedded heating
Hydronic floor heating circulates liquid through pipes, usually made of synthetic material, sometimes metal. Electric floor heating relies on a resistive cable laid in a serpentine pattern, often fixed to a mat before the screed is poured.
The distinction is not cosmetic for a survey. A pipe and a cable share neither cross-section, nor content, nor contrast with the surrounding concrete. What reads clearly in one case can stay faint in the other.
Nor is it cosmetic for what follows. A pierced pipe announces itself through a leak, visible and traceable. A severed cable breaks a circuit, sometimes with no immediate sign at the point struck, and the repair means finding the break under the floor covering.
What a heated slab changes before an opening
Heating occupies the usable thickness, the same space where reinforcement and sometimes conduits run. An opening that only had to miss steel now has more to miss, in a space that has not grown.
Preparation changes as well. A loop may be pressurised or a circuit energised to support certain checks, which is for the building manager or the contractor concerned, not for the survey. Those decisions are made before the visit, not during it.
The GPR locating method is developed on the concrete scanning page, and the terms used here are defined in the glossary.
What a survey establishes, and what it leaves open
A survey locates items and delimits areas where drilling carries more risk. On a heated slab, it mainly helps move an opening towards clear space rather than aim between two closely spaced runs. That shift is often the whole value of the exercise, because a few centimetres to one side can turn an opening from delicate into ordinary.
What it does not say is worth settling in advance. It does not indicate whether a circuit is in service, whether it has already been repaired, or what layout the drawings announced. Nor does it replace the documents of the structure where they exist.
The guide ASTM D6432-19, Standard Guide for Using the Surface Ground Penetrating Radar Method for Subsurface Investigation describes the investigation method used, and the report ACI 228.2R-13 reviews the families of non-destructive methods applicable to in-place concrete.
What makes a heated slab harder to read
Several conditions often stack up on this kind of structure, and they are better flagged in advance than discovered on the day.
- A bonded covering, tile or membrane, adding an interface to interpret
- A screed poured over the structural slab, with two materials stacked
- Closely spaced runs, where neighbouring passes blur together
- A reinforcement layer above the heating, masking what lies below
Preparing a request on a heated slab
A few items gathered before the visit change what the survey can establish, and avoid a second trip.
Say that the slab is heated
It sounds obvious, and it is still the item most often left out of a request.
State the family, if it is known
Pipe loop or electric cable. If nobody knows, say that too.
Gather what documents the installation
Layout drawings, the system data sheet, photographs taken before the pour, earlier service reports.
Describe the covering and the screed
What the covering is, whether a screed was poured over the slab, and what can or cannot be cleared.
Name who decides the state of the system
Energising, isolating or pressurising is for the manager or the contractor, agreed before the visit.
Describe your situation
General survey preparation is covered in the article preparing a site for concrete scanning. For a current project, describe the area, the covering and the planned opening on the contact page.
Frequently asked questions
Can you tell a slab is heated without a survey?
Clues exist, such as a manifold in a wall, a floor thermostat control or a mention in the building documents. They remain partial. A survey adds indications on the area examined, which the manager cross-checks with what is known about the system.
Is a heating cable located like a pipe?
Not in the same way. Cross-section, material and content change the signal response. Readings stay possible in both cases depending on conditions, but interpretation calls for knowing which system is installed.
What if the layout drawings cannot be found?
The survey is then framed on what can be observed and on the planned opening. Mention the missing drawings in your request: it changes the grid used and what the report can state about areas not examined.
Does the survey make drilling safe?
It documents what was detected under the conditions of the survey and helps choose a location. The decision to drill, the precautions and responsibility for carrying out the work remain with the contractor and the parties on site.