Corrosion mapping · Quebec City
Corrosion mapping in Quebec City
Corrosion mapping locates the zones where reinforcing steel is likely corroding in a concrete slab or wall, so that repairs can be targeted in Quebec City. Surface conditions and survey timing are part of scoping corrosion mapping.
Quebec City
Working in Quebec City
For mapping in Quebec City, surface conditions and the survey period are part of the scoping. Mention wet areas, coatings and access to parking levels. If earlier measurements exist, provide the grid, methods and conditions of those tests. A comparison between two campaigns must account for these differences. The observations help prepare the investigation and repairs with the professionals responsible for the file.
The timing of the survey is chosen around how the premises are run, and it is recorded in the report. The same area examined at two different moments can read differently, and that information belongs to whoever reads the map as much as the measurements do.
Surface conditions are prepared like everything else. Clearing, removing temporary protection and reaching the measurement points are agreed before the visit, failing which part of the announced sector drops out of the survey and has to appear as not covered.
In Quebec City, the City indicates that it can give a first response to a permit request within 30 to 60 working days. It is therefore wise to plan concrete surveys early in the project, before filing the plans.
Preparing your project in Quebec City
- Report wet areas and coatings
- Provide the grid and conditions of earlier measurements
- Choose the survey period with surface conditions in mind
Four centuries of Quebec City buildings and what they mean for concrete
The Old Québec heritage site covers about 135 hectares and has nearly 1,400 buildings built from the 17th century onward, divided between the Upper Town, on the Cap Diamant promontory, and the Lower Town, between the cliff, the Saint-Charles River and the St. Lawrence. Its fortifications encircle the Upper Town for more than four kilometres, UNESCO inscribed it on the World Heritage List in 1985, and 470 archaeological sites are known there. The Répertoire du patrimoine culturel also notes that its enhancement, after 1960, came with several historical reconstructions.
Around the historic centre, La Cité-Limoilou lines up postwar houses, narrow working-class faubourgs and three-storey brick buildings with wrought-iron stairs and balconies, along with an industrial zone to the east, around avenue D’Estimauville. In the heart of the city, the Les Rivières area only took on an urban character from the 1950s; it includes the Armand-Viau, Cardinal, Frontenac and Métrobec industrial parks and part of the Parc technologique du Québec métropolitain.
Beauport became a bedroom suburb during the 1960s and 1970s, while keeping a linear historic district of about six kilometres along avenue Royale. Charlesbourg, which became a suburb during the second half of the 20th century, retains the Trait-Carré, a star-shaped village designated a historic district in 1965.
Les Rivières, Beauport and Charlesbourg were urbanized during suburban expansion, between the 1950s and the end of the 20th century. A manager responsible for several buildings from the same period can plan a common method and grid, so that surveys can be compared from one building to the next. For each structure, indicate earlier repairs, membranes and the planned season: different measurement conditions complicate the comparison and must be recorded in each report.
Measuring corrosion activity
The ASTM C876 test method covers the estimation of the corrosion potential of uncoated reinforcing steel in concrete, for the purpose of determining its corrosion activity. Taken on a grid, these measurements produce a map of the surveyed surface.
Exposed slabs and parking garages
Parking garages are subject to specific obligations in Quebec: an annual visual verification and an in-depth verification report by an engineer every five years, according to the Régie du bâtiment du Québec. A corrosion map helps locate the zones to watch between these verifications.
- On a cracked or spalled parking slab
- Before planning concrete repairs
- To monitor an area that has already been repaired
Mapping method, process and limitations
How potential measurements work, how the survey runs, how to read the maps and their limitations are covered on our corrosion mapping in Quebec page. This page only covers what is specific to Quebec City.
Frequently asked questions
Does corrosion mapping indicate the strength of the structure?
Not directly. It provides information on the corrosion activity of the rebar; assessing structural capacity is an engineer’s responsibility.
Why combine it with a concrete scan?
Ground-penetrating radar locates the rebar and estimates its depth, which helps position corrosion measurements on the steel.
Can a new map be compared with an earlier campaign?
Yes, if the grid, method and measurement conditions are documented. Differences in method or conditions must be considered before concluding that anything has changed.
Do wet areas distort measurements?
Moisture can influence some measurements. Report wet areas and coatings in the request: conditions at the time of the survey must be documented with the results.
Sources
- ASTM C876-22b, Standard Test Method for Corrosion Potentials of Uncoated Reinforcing Steel in Concrete
- Régie du bâtiment du Québec: Parking garages, maintenance and inspection
- Ville de Québec, #AccentLocal blog: Comment bien préparer sa demande de permis, April 10, 2026 (in French)
- Répertoire du patrimoine culturel du Québec: Site patrimonial du Vieux-Québec (in French)
- Ville de Québec: Site patrimonial du Vieux-Québec (in French)
- Ville de Québec: La Cité-Limoilou borough (in French)
- Ville de Québec: Les Rivières borough (in French)
- Ville de Québec: Beauport borough (in French)
- Ville de Québec: Charlesbourg borough (in French)

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