DarkDraught marking appears on carpets as dark soiled areas or spots around the edges of rooms and under doorways. In extreme a cases it is found across the middle of a room in the configuration of the floorboards.It is also known as filtration soiling, fogging or dust marks. The cause is always the same! Contaminated air blows through or across the carpet and the carpet acts as a filter, removing any dirt from the air. The resultant draught marking is both unsightly and a problem to remove. Only a very dark coloured carpet will not show the effects of draught marking.The contaminated air can get to the carpet through any of the following• Gaps under the skirting board• Gaps between the floorboards• Holes in the carpet (caused by by nails or carpet fitting tools).• Gaps under doors Prevention Draught marking is relatively easy to prevent and very difficult to cure. A properly fitted carpet will rarely exhibit draught marks because the floor beneath will be sealed before the carpet is fitted This prevents the movement of sir through the carpet. This rnay involve the following:• Laying sheets of hardboard on top of the existing floorboards• Taping all joints between the hardboards to prevent air getting through.• Laying paper on top of the hardboard to add extra draught proofing.• Sealing the gap beneath the Skirting board with flexible mastic. If these measures are carried out before the carpet and underlay are installed then it is unlikely that draught marking will occur. (except in doorways). The British Standard (BS 5325:1983) for the installation of carpets states that any gaps in the sub floor beneath the carpet should be sealed to prevent the incursion of airborne dust. In our experience most problems occur because the gap underneath the skirting board is not sealed, even through the rest of the floor may be. Cure Most draught marking can not be removed, only some. The microscopic airborne soiling is tenaciously oil bonded to the carpet fibres. The degree of success in the removal of the soil depends on the nature of the soil and the length of time it has been present we have researched and tried many ways of removal and once you have draught marking it there to stay ,and if can be removed, it will come back, with in weeks.