You keep a clean house, dust and vacuum regularly, yet you still have black lines on your carpet. You’ve had the carpets professionally cleaned, but the lines came back. Relax, it isn’t your fault, and the problem can be fixed, permanently!
While there can be several reasons that black lines can appear on carpet at door thresholds, along walls, and on stairs, we will focus on the lines that form along walls and on stairs. The root cause of these lines is not poor housekeeping or cheap carpeting; it is actually air infiltration in your home!
During the construction of your home, the joints between the wall and floor were not sealed, nor were the gaps in the stairs (they never are). If these gaps communicate with the unconditioned space in your crawl space, basement or attic (and they often do), air is moving between the inside of your home, and these spaces.
If your home is under negative pressure (air is being pulled into your home), this can draw the dirt, dust and other particulates from your attic, crawl space or basement into your home. As these particles hit your carpet, they stick to it, building up to create the black lines you see.
Conversely, if your home is under positive pressure (air is being pushed out of your home), particles inside your home from leaks in ductwork, candle and fireplace smoke, cooking smoke, household dust, etc. are being drawn through your carpet as they are pulled through these gaps. As these particles hit your carpet, they stick to it, building up to create the black lines you see.
The infrared picture below shows what the naked eye can not see. The bright yellow areas are warm, heated by the warm air in the home during winter months. The dark purple areas are cold air, being pulled into the house from an unconditioned crawl space due to negative pressure inside the home. The contaminants in this air are being captured by the carpet, creating those nasty black lines.
So what is the solution?
- Having the carpet pulled back, and caulking the gaps between the wall and floor or between the stairs, can help to resolve this problem.
- Care must be taken to ensure you do not make your home overly tight, as this can lead to a whole new set of problems.
- If more clean air needs to be exchanged, this can be done through mechanical systems that can filter and condition the air as it enters your home.
For more information, contact BelRed today.
