Draft marks | Dark Lines On Carpet

Michael Mckenzie
November 3, 2023
5 mins read
Social Media
Draft marks | Dark Lines On Carpet

Dark lines

Have you ever wondered what those annoying dark lines on your carpet around the edge of the room are? They certainly can look awful! They can also appear as random dark spots in the same pattern over and over again. Weird huh? In the industry, these are called draught marks or filtration soiling.

Filtration soiling occurs as a result of air being forced into a room or space at a higher rate than it can escape from the same area (opening and closing a door, as temperature rises and falls, etc). The air then seeks alternative escape routes, which usually ends up being the gap between the carpet and the wall trim and under closed doors.

As the air is forced through these gaps, it passes through the carpet, which acts as a filter to the air. Any pollutants in the air are trapped by the carpet and turn the carpet darker in that area. Common pollutants that can contribute to the problem include smoke from cigarettes and candles, cooking oils, fireplace ash, and dust.

This soiling does not occur as a result of insufficient vacuuming or improper vacuuming techniques (although consistently failing to vacuum the very edge of the room can amplify the problem). It is a problem that can occur in the cleanest of homes and is not considered a reflection of housekeeping abilities.

The soiling is generally from vehicle fumes, especially diesel, if you are near a busy road. So, it is greasy and clings to the fibres. It often leaves a permanent greyness to the carpet that cannot be reversed. When you see it in the form of loads of dots around the room, this is where the carpet fitter has punctured the carpet backing with his knee kicker when stretching the carpet, and air flows through these holes.

So, what can you do? The next time your carpet is lifted or if you have a new one fitted, ask the installers to install some filter paper under the carpet. You can also seal the gaps with some caulking/sealant to prevent any airflow.

Michael Mckenzie
Owner, Paramount Cleaning Company
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