How do you clean Red Clay stains? Ryan Cash and Rooftec Systems

RyanCash

Member
There are a few areas in the country (normally in the south east) that have red colored clay/soil. But what causes it to be red?


All soil in the world forms result from a combination of climate, organic life, inorganic material, relief and time. These specific soils have a red tint due to the presence of iron oxide.

Areas with red clay tend to have a climate of warm (hot) temperatures and high rainfall, so there has been intense weathering of the foundational rocks underground over the years. High rainfall has leached out most of the bases that were present, leaving materials that are composed mostly of iron, aluminum, and silica.

The red color is not just from the iron, but more specifically from iron oxides. (Rust is another example of a type of iron oxide)

Sometimes, the organic material inside the soil can mask the red color, but many of these areas where this type of soil is present, organic matter content is low.


In 1975, the US Department of Agriculture Soil Survey said,

"The red color of soils is generally related to unhydrated iron oxides, although manganese dioxide and partially hydrated iron oxides may also contribute red colors. Since unhydrated iron oxide is relatively unstable under moist conditions, red color generally indicates good drainage and good aeration. Strongly red soils are expected on convex surfaces underlain by pervious rocks.​
In regions where the normal soils have red color, the well developed red color is one indication that the soils are relatively old or at least that the soil material has been subjected to relatively intense weathering for a considerable time."​



So the next question is, Why does any of this matter?


Areas that have red clay will inevitably have red clay stains. These stains will be most common on concrete and also the first foot or two of siding, closest to the ground.

Since these red clay stains are inorganic, a normal house wash (Sodium Hypochlorite) will not even begin to touch the staining.



Instead, specialized chemicals are needed to remove these stains.

Rust remover work really well here. You’ll need to be careful though as many of these rely on acids to clean, which can be damaging to certain substrates.



A great alternative that works extremely well is RoofTec’s Contec. It can be purchased online and is a high alkaline cleaner that works to lift the iron oxide and allow it to be washed away. Contec is also a great degreaser and can cut through most stains on concrete.



Just like everything else, you always want to start with the least intrusive method possible and the lightest pressure. Build up in strength and pressure as needed. (Always TEST!)

Only after exhausting all other methods should you switch to an acid that can be potentially dangerous.
 
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