Sometimes especially on light coloured carpets, you can see a dark line against the skirting board, or a rectangular mark just in from the edge of the carpet, a dark line under a doorway or in line with the floorboards. These marks are known as draught marks and are caused by small particles of dust working there way through the carpet from underneath the floor and been trapped by the fibres in the carpet.
Carpet cleaning can be effective in removing them from the carpet fibres, however in some cases it may not be possible to remove them completely, and unless action is taken to stop the soiling moving from underneath the floor through the carpet the draught marks will return.
Action that can be taken includes sealing the area under the skirting board with a flexible filler and placing a paper barrier underneath the underlay these measures will form a barrier to prevent the fine particles moving to the surface of the carpet
causing draught marks to appear