IRON OCHER
What is it about?
In the presence of water and oxygen, the iron present in the soil oxidizes, thus forming an iron hydroxide sludge which gradually clogs the French drain as well as the catchment basin located in the basement of the property. This deposit is first observable on the internal face of the drains and the catchment basin and can thus block it partially or completely. The iron ocher phenomenon is pernicious since it can cause significant damage before the owner even realizes it.
There are two types of ocher deposits: deposits of bacterial origin and those resulting from a chemical reaction. The soil types that appear to have the greatest potential for the formation of ocher are fine sands, silty sands, organic soils and soils containing mineral matter. Also, we can notice the presence of this problem when the drains are located in a potentially floodable location, such as at the bottom of a slope or in an area where the water table varies.
Soils rich in iron and ferrobacteria will produce iron deposits indefinitely. It is therefore very difficult to eliminate it. Even if the soil around the building were replaced, iron from surrounding soils would migrate back to the property drain through natural water runoff.
To prevent the development of the bacteria, the two natural elements of water and air would have to disappear from the soil, which is impossible. It is therefore not possible to prevent the chemical reaction which creates iron ocher.
It is sometimes possible to see deposits of ocher floating on the surface of the stagnant water in the ditches. A laboratory analysis confirming the presence of Fe2+ in the soil indicates the reaction potential of iron ocher. Iron ocher does not constitute, in itself, a health hazard. The multiplication of mold caused by humidity can, however, lead to serious air quality problems, with very serious consequences for health. In some serious cases of mold contamination, public health experts may outright recommend evacuating the home.
Considering the widespread presence of iron in Quebec soils and aware of the significant damage that iron ocher can cause, it is essential to have the soil analyzed before signing anything to prevent owners and future owners from experiencing such nightmares.
Before purchasing a property in a risk area, refer to the results of a soil analysis to make your decision. New or existing homes, municipalities, builders and brokers remain rather reserved on the subject. Despite the possible fixes to be made to buildings, despite the fact that iron ocher is covered by the guarantee plan in the case of new construction, you will only alleviate the symptoms to your great dismay. The only truly proven solutions to iron ocher, such as waterproof casing of the foundation, lifting the house out of the affected area, and filling the basement with granular materials (condemning the basement), cost a real small fortune. As for the other techniques, none has yet really proven itself.
Possible fixes:
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changing the slope of the land
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sealing at the junction of the concrete wall and the concrete slab
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installation of cleaning chimneys
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drainage under the slab
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the installation of a water-repellent coating
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the installation of a waterproofing membrane
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raising the basement slab
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condemning the basement
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house uprising
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waterproof casing of the foundation
Risk area:
(please note that this list is provided without reservation and for information purposes)
|
Alma Bécancour Cap de la Madeleine Deschaillons Herouxville Sergeant Lake Lanoraie Laterriere Laurier Station Magog |
Mont-Laurier Neufchatel Neuville Nicolet Sainte-Adèle Saint-Agapit Saint-Amable Saint Canute Saint-Colomban |
Holy Cross Saint-Étienne-de-Valois Saint-Hélène-de-Breakeyville Saint-Gabriel-de-Valcartier Saint-Ignace-de-Loyola Saint-Jean-de-Matha Saint-Maurice Saint-Nicéphore Saint Nicolas Sept-Îles Sorel-Tracy |
Source ACQC
Useful links:
www.radio-canada.ca/actualite/v2/lafacture/level2_11797.shtml
