What are the Black Lines by my Baseboards
Filtration soiling is a situation that many homeowners see in their homes and is something that might become permanent. You will notice this as a black or dark gray line around baseboards, doorways where a door is closed a lot, or on stairways or even around furniture that has skirts close to the carpet. You might be wondering how filtration soiling gets in the carpet in the first place? This is not a carpet defect, but is caused by air passing through the carpet as it goes under a door, wall, or furniture. When this happens, any dust or other particulates that are in the air become trapped on the outside edge of the carpet fibers.
As air passes through the carpet, it acts similar to your HVAC filter and picks up the dust, soil and other pollutants from the air. The condition may happen slowly over time or come on very quickly, depending on the volume of air flow through the carpet and how many airborne pollutants there are in the air. This condition is also not covered under most carpet manufacturer’s warranties and can happen in bargain priced carpet or in high end carpet, so the price and / or quality of the carpet have nothing to do with it. Filtration soiling will be more noticeable in lighter colored carpets though. Preventing airflow through the carpet by sealing cracks in the subfloor, under baseboards, and the inside of your HVAC air return may help eliminate the problem in those areas. However, if you have a piece of furniture that this is happening around then there may not be a way of preventing it around that furniture.
If you have this condition in your carpet now and are wanting to replace the carpet make sure to try and caulk between the subfloor and the base of the wall before putting down new carpet. Also, try to pick a darker color of carpet. These two things could help ensure that this doesn’t happen to your new carpet too, but if it does it shouldn’t be as noticeable on darker colored carpet.
Removing the filtration soiling after it is found, can be a challenge even for a professional carpet cleaner. It generally takes a highly alkaline cleaner and some scrubbing action followed by hot water extraction to remove the lines if they are going to come up. The longer it is left in the carpet the harder it will become to remove. Thankfully as carpet protector technology has increased it has made it easier to remove the filtration soiling. However, total removal may not always occur and if the cause of the problem is not solved, then it will return eventually after a cleaning.