Grey or black lines along the wall

You probably do not want to know this, but it is not a defect in your carpet. It is called soil filtration and is a concentration of dirt that has collected on the carpet fibers

Soil Filtration is caused by air flow from positive and negative pressure within a building. For example, when warm air rises or your heating and air conditioning system come on, pressure change occurs within a room. Air will then try to flow either in or out of the room. Based on the construction of the home, this can happen along the wall edges. As the air moves over the carpet fibers, they serve as a filter and grab the dirt in the air. The result is the dark or gray line on your carpet along the walls.

 

Have you ever noticed a grayish or dark line at the doorway of a room, especially for a room where the door is shut most of the time? Once again, soil filtration as described above. When there is a slight pressure difference between two rooms, air will try to flow from the room with the higher pressure to the other room through the largest available holes. With the door shut, the undercut of the door is generally the largest available hole. Therefore, as the air passes between the door undercut and the carpeting, the carpet acts like a filter taking out dirt and dust particles from the air. Over a period of time, the carpet will darken as the dirt accumulates.

Because soil filtration is a concentration of dirt particles, cleaning it can be very difficult and in many situations not cleanable at all.For more information visit our website at www.graysoncleans.com