[justin brown]

Hi all, i went round to clean a ladys stair carpet last week as right on the edge of the first few steps were a black mark (the carpet was a wool loop pile). The owner thought it was were he wears socks and wraps his toes around the end of the stair as he goes up and down!! I put some prespray gold down, followed by extracting and then a little citrus gel and extracted again. When i left the dark edges seemed darker due to the dampness on the carpet, i thought they would dry out but i had a phone call saying the 'stains' were now darker..maybe my first case of wicking? Any suggestions please for when i have to go back round again head bowed to try and get a better result please?!!!

[Colin Day]

I had something similar happen last year. It turned out that the carpet was really old and the rubber backing/underlay had perished into a fine powdery substance which was brought to the surface during the extraction phase....

[Bob Allen]

Alot of people including myself hardly vacuum their own stair so it always worth giving the "noses" of the stairs a good pre-vac bedore you clean them, sometime worth toweling them off after aswell.

[John Milnes]

You won't get a better result. The problem is due to the looped pile being crushed and reflecting light in a different direction (shading). Also the wear to the edges will result in the carpet having lost it's colour. This will happen in wool carpet but not so much in synthetics.

Another factor is the pile being open and exposing the underlay, resulting in darkening which will be mistaken for being dirty.

No matter what you do it will still look the same.

[Jamie Pearson]

Is it draught marking?

[markpowell]

Powerburst prespray, brush in then extract, accross the edge, then front to back, then towel, and repeat if needed,m you can get good results
MARK

[cleanable]

I would go with Colin's diagnosis. Underlay delamination pulling through to surface. Rubber Underlay goes into a powder like substance when no good anymore, this is what is drawing up to the surface.

Remedy.... take up carpet (on that bottom tread only), lift old underlay pad, thorough vacuum area, replace new underlay, re-fit carpet, job done.

Re-clean using as least water as poss (low psi).

Carpetguy's idea of a loop pile carpet (or berber) having a shading (or pile reversal) problem is IMO very unlikely....

[AJB]

Loop pile is the give away,
It's grinning.

[justin brown]

thanks guys, really appreciate this

[robert meldrum]

This is a common problem and if all else fails I use dry foam with a bonnet pad ( any bonnet would do )