Filtration soil is the dark spots or lines around the perimeter of a room, on stairwells, at thresholds or near vents. It appears worse on light colored carpets. It is a buildup of indoor pollution that you can actually see!
Air comes up from a void, under stairs or a subfloor, with microscopic dust and soil and filters through the carpet. Air can also be coming up through cracks, improperly seated or seal joints or areas of concentrated air flow. Carpeting acts as a filter for all of this. The dust, soil and debris catch the edge of the fibers gradually forming grey to black spots and lines. Be grateful for your carpet! If it wasn't there to filter all of that your lungs would have to.
Fact: 80% of the dirt on carpet and upholstery is particulate soil. That's soil from the bottom of shoes or in the air.
The Extreme Steam tackles filtration soil frequently. Here's how we do it:
Fist we do a test on the area that is the worst. This is to make sure that we can get it up. We don't want to over promise or waste time scrubbing if it isn't going to come up.
Next we apply a product called Filter Out and let it dwell for several minutes.
After that it's down on our hands and knees scrubbing with a light brush.
The final step is to towel up or steam extract with a neutralizing rinse.
How we attack this type of soil does depend on what it is next to or up against. If the carpet is up against a baseboard with a semi-gloss we can be more aggressive. However if the carpet is only up against painted sheetrock we have to be more delicate with it.
We can help in the short term but if you want a long term solution you should be thinking about calling a contractor. This is definitely something to discuss with your contractor if you are building a home or addition!