Concrete scanning · Montreal
Concrete scanning and GPR in Montreal
In Montreal, concrete scanning with ground-penetrating radar (GPR) locates rebar, conduits and other embedded items before you core, drill or cut a slab, wall or column. The survey is often prepared in an occupied building or parking garage where several parties share the same access.
Montreal
Working in Montreal
In Montreal, a renovation project may bring together the property manager, the condominium association and several contractors. For a slab scan, indicate the position of the openings and the elements to be crossed. In a parking garage or an occupied building, the survey area must be cleared and marked on a shared plan. Traffic, noise and site protection constraints should be discussed before the visit. Having drawings does not remove the need to check that they match existing conditions.
In a Montreal building held in co-ownership, the survey area often belongs to the common portions, even when the opening serves a private unit. The syndicate then decides on access, working hours and the protection to be installed, and the contractor cannot commit to the schedule alone. Confirming this before the visit avoids a postponement once the crew is on site.
An indoor parking level adds a traffic constraint: the spaces within the working area have to be cleared, and a window agreed where vehicle movements remain compatible with a regular sweep. On a garage floor, a protective coating or a bonded membrane changes antenna contact, which is worth flagging in advance rather than discovering on the day.
Concrete scanning in Montreal is not prepared the same way for every building. In a plex in the Plateau-Mont-Royal, Rosemont or Villeray, the opening often targets a basement slab or a foundation wall, with tight access. In a downtown or Griffintown office or condo tower, the structural slab may contain electrical conduits and, at times, post-tension cables. In a multi-level parking garage, a store or an institutional building, the area is planned with the occupants. Describe the building type and the floor in your request: that is what shapes the survey.
In Montreal, construction, alteration and demolition permits are issued by the boroughs, each of which has its own service counter. If coring or a new opening is part of alteration work, check with the borough concerned.
Preparing your project in Montreal
- Mark each planned opening on a plan shared by the manager and the contractors
- Ask the borough whether the coring is part of alteration work that requires a permit
- Agree on traffic, noise and site protection constraints before the visit
Montreal’s building stock and your concrete surveys
Montreal industrialized along the Lachine Canal. According to Parks Canada, its first industrial boom began in 1848, when the first widening of the canal made a new power source available. More than 600 businesses have occupied the neighbouring land since the canal was built: flour mills, foundries, shipyards, a sugar refinery, then chemicals, petrochemicals and iron and steel production in the western section. The thousands of workers who settled near the factories gave rise to the working-class neighbourhoods of the South-West. Near the canal there are still 40 industrial complexes grouping more than 200 buildings.
On the residential side, Héritage Montréal describes the typical triplex as a building with three civic addresses, often built in series by an owner-developer or a contractor. In the 1920s, many triplexes adopted dark brick facades with artificial stone inserts. They are common in Verdun, the Plateau-Mont-Royal and Rosemont, among others. The early 20th century also brought “shoebox” houses, small one-storey single-family homes, often without a basement, found in Villeray and Hochelaga-Maisonneuve.
Beneath the city, the metro forms another generation of structures. According to the Répertoire du patrimoine culturel du Québec, construction began on May 23, 1962, and the metro opened on October 14, 1966, with 20 stations on two lines. At street level, the City states that it spreads salt and crushed stone as soon as roadways and sidewalks become slippery.
A complex in the Lachine Canal corridor may have had several occupants and several extensions. A slab poured during a conversion may sit next to a much older floor, and nothing suggests their reinforcement follows the same logic. Before coring, ask which wings were altered and when, then plan a separate scan for each part rather than a single assumption for the whole building.
For a triplex or a shoebox house, start by stating which concrete element is involved: foundation, basement slab, balcony or stairs. The answer determines the accessible face and what the survey needs to look for.
How ground-penetrating radar works
Ground-penetrating radar (GPR) emits high-frequency electromagnetic waves and records their reflections at boundaries between materials with different properties, such as concrete and steel. The ASTM D6432 guide describes this investigation method.
GPR is also one of the non-destructive test methods for in-place concrete reviewed by the American Concrete Institute (report ACI 228.2R-13).
Method, preparation and GPR limitations
When to request a scan, how to prepare the survey, how to use the findings and what ground-penetrating radar cannot see are all covered on our concrete scanning in Quebec page. This page only covers what is specific to Montreal.
Frequently asked questions
Does concrete scanning damage the structure?
No. GPR is a non-destructive test method: the device moves over the concrete surface without drilling or coring it.
What can ground-penetrating radar detect?
Usually rebar, conduits and other embedded items whose electromagnetic properties differ from those of concrete. Readability depends in particular on depth and on the condition of the concrete.
Who should be informed before a scan in a Montreal condominium?
The manager or condominium association, who coordinates access to common areas, and the contractor responsible for the opening. Share the plan of proposed openings with them before the visit.
Is a scan useful when the opening is in a common area?
Yes. In a common area or shared parking garage, the survey helps locate embedded items before the work. Access, clearing the area and timing are agreed with the manager or condominium association.
Sources
- ASTM D6432-19, Standard Guide for Using the Surface Ground Penetrating Radar Method for Subsurface Investigation
- American Concrete Institute, ACI 228.2R-13, Report on Nondestructive Test Methods for Evaluation of Concrete in Structures
- Ville de Montréal open data: Permis de construction, transformation et démolition (in French)
- Parks Canada, Lachine Canal National Historic Site: The cradle of industrialization
- Parcs Canada: Le berceau de l’industrialisation, French version with the current industrial complexes (in French)
- Héritage Montréal: What is the personality of your home?
- Répertoire du patrimoine culturel du Québec: Inauguration du métro de Montréal (in French)
- Ville de Montréal: Snow removal on sidewalks and streets
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