Speciality Services

Iron Ochre Testing

Iron Ochre Testing

To help you save time and unnecessary trips, AmeriSpec Laval, No rth Shore, Montreal East now offers to do your Iron Ocher sampling.

No need to make another appointment, AmeriSpec takes care of everything.

What is iron ochre?

Iron ochre results from a chemical reaction or a biological process, and both of these may occur either individually or simultaneously:


Chemical reaction: When the soil contains iron, it migrates along with the water towards the drainage system. When it comes in contact with the atmosphere, it forms a sludge of iron hydroxide.

Biological process: When iron bacterium is present within the water table, this bacterium, following oxidation of the iron upon coming into contact with the atmosphere, produces a gel-like mass.

When the biological process adds up to the chemical reaction, the oxidation effect is considerably increased.

Both cases result in the formation of a viscous deposit on the corrugated wall of drain pipes.
This deposit is what we call iron ochre.

What conditions give rise to iron ochre?

This substance is more likely to develop in a more aerated soil, such as the sandy soils containing silt, and will less likely develop in clay soils.

The chemical or biological reaction is also quicker:

  • where soil tends to be neutral (pH of approximately 7);
  • when the wall of the drain is corrugated;
  • when the openings of the drain are punched instead of cut out, which creates attachment zones for the deposits;
  • when the drain is wrapped in a filtering membrane.

Under the action of iron ochre, even crushed gravel loses its filtering properties. The soils rich in iron and in iron bacteria will produce ferrous deposits indefinitely.

What consequences has the presence of iron ochre?

Iron ochre causes several issues with buildings:

  • It causes ocher-colored slimy sludge deposits to accumulate in the rain water catch basin and in ditches.
  • It creates reddish deposits on the concrete slab of basements. These deposits give a sulfur-like odour.
  • It obstructs agricultural tile drains: since runoff water is no longer channelled at a distance from the foundations, it infiltrates the basement, at the junction between foundation walls and slab.
  • It obstructs the backflow valves.

*Information provided by the Régie du Bâtiment du Québec web site

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