Characteristics of Carpet Stains
When it comes to stains on carpets, there are typically two types of stains on carpets. There are surface stains and there are deep stains. Surface stains are the result of substances like dirt, grease, sap, or other stains related to foot traffic, or small stains resulting from small spills. These stains are usually just on the surface or face yarns of the carpets. Since these stains are surface orientated, they will clean off fairly easily unless they have affected the dye structure of the fibers. Items that contain bleaches, acids, or other dyes can all affect the existing dye structure which can remove, lighten or alter the existing color of the fibers and may require some special attention to try to restore the carpet to its’ previous condition. These special treatments used to restore the carpet fibers to their original color are above and beyond your typical cleaning and you should expect additional costs related to these efforts.
Then we have stains that are much deeper into the carpet fibers and are usually caused by spills of a larger nature. These could be anything from a drink or a whole cup of coffee spilled, a pet stain, a plant that was overwatered, or even a leak in a ceiling to a leaky pipe. All these have one thing in common. They not only wet the surface yarns, but they also wet the entire rug including the primary and secondary backing of the carpet and even the padding and in some cases the subflooring. The problem with this type of stain is quite often the fibers in the backing can contain materials like cotton and jute or other natural fibers, all of which are negatively affected when they get too wet. Some of the issues you will or could experience are shrinkage and bleeding as well as weakening and even rotting of these fibers. Fibers like cotton and jute are cellulose fibers and the bleeding that can occur is known as cellulose browning. Cellulose fibers come from plants and this browning is caused by a naturally occurring gum called lignin. The jute will bleed this brownish lignin when it gets too wet. This bleeding is a slow process, so it usually is not evident at first, since it occurs once it has been too wet for a while and the drying starts to take place.
A Typically example of this is when a stain happens such as a pet urinates on a carpet and the urine seeps into the back of the carpet getting the jute too wet. The urine will break down the jute and cause the release of the lignin. This takes time, so while this is breaking down, the stain on the surface dries. The jute is in the beginning stages of breaking down so there is no visible sign of this damage that appears on the surface or face yarns yet. As soon as the stain is cleaned, the moisture used to remove the urine completely will come in contact with the jute that has been damaged in the backing of the carpet. That moisture will act as a carrying agent of the lignin and will cause the brown staining to wick to the surface as it dries. So, regardless of the initial results, once an attempt to clean the stained area, the result will be a brownish stain on the surface fibers once it has dried.
What everyone needs to realize is what caused the damage? It was the urine coming in contact with the jute and getting it to wet, not the cleaning attempt to remove the urine. Normal cleaning is confined to the face yarns and does not get the backing wet. The urine did get the backing too wet. This is what broke down the jute and caused the damage. Another example of this is when a plant is consistently overwatered and no one ever moves the plant to realize this. So this constant repeated over wetting not only breaks down the jute but also spreads and migrates laterally causing a very large stain in the backing of the carpet. So even though you now move the plant and see a 6-inch stain on the carpet, there might be a stain as large as 24 inches in the back of the rug. Once the carpet is cleaned, any residual from the overwatering like dirt and migration from the jute will wick to the surface and you’ll now see a 24-inch stain on the carpet face yarns once dry.
Again, what was the cause, the cleaning or the overwatering of the plant? Yes, you get the picture now. These are all preexisting conditions that are not visible at first but they are present and all caused by the initial overwetting.
In most cases, the resulting problem can be effectively resolved with multiple re-cleaning applications alone with special treatments based upon the type of face yarns in the carpet. The consumer should be aware of this and understand any subsequential cleaning should be at the expense of the homeowner and not consider that the carpet cleaner caused this or should be at his expense.