Ever wonder how ‘dark’ lines accumulate on the perimeter of rooms along baseboards, under doors, or down the sides of a stair case? In the professional carpet cleaning world, we call these “Filtration Lines”. They are caused by dirt, dust, soot and pollutants circulating throughout the house and sifted through every crack of the house, depositing onto the carpet fibers adjacent to the crack, and eventually display the dark lines or areas. Because the deposition (filtration) takes years to develop, your house may not show any filtration lines for 5 or more years. It’s a sign of age to any experienced carpet cleaner.
If you are installing new carpeting or you fear your house may be subject to filtration lines and you want to ensure these lines don’t appear, a more permanent solution is necessary. This is a construction issue and you must eliminate the crevice between the floors and walls as well as the wood cracks (seams) of the steps. Every crack or seam of the steps must be caulked and sealed. Baseboards will need to be reset (onto the floor) while caulking. Eliminating the possibility of airflow through the cracks in the house and onto the carpeting, eliminates the problem. Unfortunately, nothing can be done to eliminate filtration lines under doors.
Once these lines become noticeable, it is too late. Cleaning will remove these lines by 75-85%. However, you'll see remaining lines in light colored carpets. The fibers have been 'dyed' (any spot left for months will dye the fiber, a very slow but effective way of dyeing). The fibers associated with this line are now a darker color. Cleaning will lighten this line by removing the more recent dirt and soot, but the dyed fibers will still be noticeable.
After these lines are cleaned-up, the deposit (filtration) causing them will continue and the lines develop again. In order to slow down this process, be sure to clean or change your air filter (1-2 times per year) at your furnace, reducing this dirt, dust, soot and pollens circulating in the house. In addition, protection (stain guarding) and refreshing the protection will help the effectiveness of future cleans.
FYI: The US Environmental Protection Agency (EPA) recommends regular cleaning the air filter at your furnace. We suggest checking this filter in early October on an annual basis. If you have central air conditioning, we suggest a check in April as well. PG&E offers this filter inspection/change as a free service to their customers; if you need help, just call them and request an appointment.
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