Iron ochre, ever-present in Quebec soils, is a bacterium that eats away at the iron. It is activated by air and water and creates an iron hydroxide sludge that gradually plugs drains, causing water infiltration problems in buildings and cracks in foundations.
Iron ochre can be formed in two ways:
- By a chemical reaction, in soils naturally rich in iron, activated by air and water, and more specifically during periods of freezing and thawing.
- By a biological process, when the bacteria is present in the water table.
In both cases, iron ochre is recognizable because of the rust-coloured deposits it leaves behind.
It’s a real problem for drainage systems, which may ultimately weaken a building’s foundation and eventually compromise its stability.
Research has been conducted around the world to try to solve this problem. Different approaches are currently being studied, such as adding material into the ground like wood chips or straw to neutralize the effect of iron, installing clean outs, or even completely sealing foundations.