WHAT ARE THE BLACK MARKS AROUND THE EDGE OF CARPET?
These dark marks are known as filtration marks. Most people think they are caused by the dust collecting in at the edge of the carpet, but this is actually incorrect. These filtration marks can appear next to skirting boards, underneath doors, along the edge of stairs and especially upon the carpet edge in any cupboard with a boiler or central heating system in it. They can be also evident along the path of floorboards where there is poor – or no underlay.
WHAT CAUSES FILTRATION MARKS?
Warm air rises, (look at hot air balloons rising for example) and this warm air contains microscopic airborne soiling. This soiling is carried through the air, through wall cavities as well as up and through gaps in floorboards.
If your carpet fitter leaves a small gap when fitting the underlay so he can install his gripper rods, then the aforementioned dirty air particles will find they’re way through. They then settle at this point (the edge of the carpet) and slowly build up over time.
It doesn’t really matter how much you vacuum these areas as they will still start to darken over time. These marks can also be caused by small puncture holes that the carpet fitter creates whilst using his tools.
HOW TO REMOVE FILTRATION MARKS.
To be honest the only real way to clean these marks is to call a professional carpet cleaner in. Specialist carpet cleaning products are needed, and these need to be extracted out of the carpet using an extraction machine.
HOW TO AVOID FILTRATION MARKS.
Best course of action is to make sure any carpet installation make sure the floor beneath the carpet is fully sealed. As its these gaps that let the filtration soiling through, no gaps = no black marks around the edge of the carpet.