Help We Have Dark Lines Around Our Carpet Edges!

Feb 24, 2022 | Allergens & dust Cleaning, Carpet Cleaning

carpet cleaning

It’s common for our potential customers to call in with questions and pictures of problems they have in and around the house. One of the common questions we receive revolves around carpet filtration lines. Most recently a lady sent in a photo of her white carpet that had ugly black stains around the base molding, under doors, and at the edges of the stair treads. Filter soil is more common than one might think. As a busy carpet cleaner here in Clinton Twp, Michigan, we see a lot of it.

Unfortunately, these black lines don’t come out with the standard carpet pre-spray and general cleaning that many carpet cleaners use. There are techniques, chemicals, and special detail tools that carpet cleaners can use to make the carpet look better around the edges.  In most cases, this eyesore can be brought to an acceptable level.  We can usually achieve an 80% improvement or better. There are some homes that are too far gone to fix, such as those that have very severe cases where the black has made its way further into the rooms and around items that have sat on the floor for a long time; items such as big desks, box springs with no bed frame, or boxes stored on the floor in closets, even on the ceilings and up the walls. Replacement with a darker colored carpet is recommended for these extreme cases.

What Is Filtration Soil And What Causes It?

The simple answer to this question is pollution within the home. The carpet actually acts as a filter, trapping very fine particles that circulate through the home. These microscopic oily particles are most commonly the byproduct of anything that burns, such as candles, fireplaces, furnaces, stoves, etc. These pollutants are then circulated throughout the home by the home’s heating and cooling system. When carpet is installed there is padding under it, except at the last couple of inches along the wall where the tack strip gets installed to hold the carpet in place. This allows air to flow down the wall cavities and pulled through the carpet edges to make its way back to the air return. If you have ever taken a light switch cover off for a painting project you can place your hand close and actually feel the air flowing through the wall cavity – homes need to breathe.

What Can Be Done About Filtration Soil?

Unfortunately, filtration soil can be very difficult to both prevent and remove once it has set in. Here are seven things you can do to help:

  1. When choosing carpet, consider a darker color, as white and other lighter colors will show this gray filter soil more.
  2. Cut back on the candle burning and fireplace usage.
  3. Replace your furnace filters regularly; we do ours quarterly and set a reminder. Unfortunately, the filters with the higher MERV ratings that are capable of catching the finer particles often are not recommended by HVAC manufacturers as they can put too much strain on the system.
  4. Keep doors to unoccupied rooms open. When the bedroom doors are kept closed the air return in the hall will suck the air out of the room from under the door, leaving a black line.
  5. Frequent vacuuming, utilizing the crevice tool along the edges.
  6. When possible, keep items off of the floor such as large boxes, and other flat items. Box springs should always be on a bed frame, never directly on the floor.
  7. Get professional carpet cleaning at least once per year.

Help From A Professional Carpet Cleaner

Once filtration soil sets in, the only hope will be a professional carpet cleaning company that is experienced in filter soil removal. They will have the right products and tools to get the job done. Because soil filtration removal is a difficult and time-consuming process it comes with a price tag. Many folks aren’t willing to go for the cost, especially knowing that it will likely return.  Many carpet cleaners will often tell customers that it simply will not come out and it is permanently stained. This is because it is such a hassle & expense. It is always worse behind furniture that never sees a vacuum. So all the furniture needs to be moved, cleaned under and replaced to their original place with furniture blocks. Most of the filter soil jobs we do are for people that need to sell their house and just don’t want to replace the carpet.

Do All Homes Have Filter Soil?

Filter soil knee kicker marks

Not every home has these filter soil issues. Some have it in just some rooms or along some walls, but not every wall. Some have it along every wall.  We have been trying to take note over the years to find patterns such as the age of home, interior wall or exterior wall, but I have not really pinned it to any of the above, it just seems some walls are more air-tight than others.

In this picture, it’s interesting that during the original installation of the carpet they used a knee kicker, which is a standard carpet installation tool, however, this knee kicker pierced holes in the carpet backing allowing air to flow through and filter soil to set in.

In this photo, there is a stair riser with severe filter soil. We see this often and this most likely took many years to set in. As you can see this was a white carpet, which I suggest avoiding for future installations.



Filter Soil Along WallsThis picture is a good example of the typical edge issue that is very common in many of our customers’ homes.