Prevention and solutions
When building an immovable, vigilance is key. It is recommended to make verifications with the municipality regarding the area’s history when it comes to the risk of ochre deposits. It is a good idea to ask the neighbours whether warning signs are already present, such as the presence of reddish water on surfaces or in the ditches after a rainfall.
It is recommended to have the current conditions assessed by a professional prior to going ahead with the construction. The evaluation will determine:
- type of soil
- pH level
- presence of iron or ferrobacteria in the soil
- annual variation in the level of the groundwater table.
If necessary, to avoid the impact of ochre deposits, certain elements of the immovable could be adapted, such as:
- position of the basement concrete slab above the water table level
- use of an agricultural drain of proper diameter, size, opening, placement and composition
- position of the geotextile membrane
- type of granular backfill
If the planned location of the construction still poses a risk, it is recommended to install two cleaning vents to allow the drain to be cleaned when needed.
Immovable for resale
When an immovable is resold, pay attention to any signs that might indicate a potential ochre deposit problem, such as high basement humidity, recent flooding, or the presence of reddish water in the ditches, on surfaces, on the concrete slab, in backflow valves or in the sump pump. This is covered by questions D9.2, D9.3 et D9.5 of the form Declarations by the seller of the immovable.
If appropriate, tests should be carried out by an expert to confirm that the problems are indeed caused by iron ochre. If necessary, corrective measures can be taken to reduce the symptoms of ochre deposits. These vary by location and may require:
- modifying the slope of the land
- sealing the junction of the concrete wall and concrete slab
- installing cleaning vents
- draining under the slab
- installing waterproof coating
- installing a waterproofing membrane
- raising the basement slab
- condemning the basement
For more details: Iron Ochre
Reminder from the FARCIQ
The real estate broker must recommend to his selling client to provide his declarations on the immovable to any person or company proposing to acquire it.
When the factors that could affect him are disclosed, the buyer has all the facts and can make an informed decision.
The seller, for his part, protects himself against actions for hidden defects.