Carpet shift marks are one of the most controversial claims in the carpet industry. Carpet manufacturers will tell you that these lines or bands are a normal characteristic and not a defect. Others in the industry often disagree. So what are shift marks and are they a defect or not?
What Shift Marks Are
Most commonly, shift marks appear as narrow lines or bands. They repeat across the width of the carpet at regular intervals. The surface of the carpet may have narrow widthwise gaps in the pile. The actual gaps can sometimes be difficult to see. Shift marks are most common with graphics or stepover stitch loop-pile carpet. They can also occur with cut pile carpet.
Carpet Shift Mark Creation
The needle bar on a carpet tufting machine can hold up to 1,800 or more needles. Tufting machines set to manufacturer 12 foot wide 1/10 gauge carpet hold 1,440 needles across its width. With step-over stitch the needle bar shifts in a side-to-side direction. The needles stitch the yarn through the primary backing material. The shifting needle bar places tension on the yarn as its pulled down.
Shift marks result from the yarn being starved or pulled down as the needle bar is shifting back and forth. This added tension results in the appearance of bands or short, little row lines that appear on the face of the carpet. These bands are the most noticeable where they line up at a seam. They often start appearing more after the carpet has been down for a while. These marks are not correctable.
Are Shift Marks in Carpet a Manufacturing Defect
No, with commercial looped carpet that is manufactured using a shifting needlebar. Sometimes its an unwanted characteristic that is not correctable.
Yes/Maybe, with residential cut pile carpet. If the shift marks are not seen in a large sample of the carpet that the consumer ordered from, they may not have received the appearance they bargained for. This may be a visual defect though the manufacturer may see it otherwise. It does become the dealer/installer responsibility not to install carpet with visual defects. While these marks do affect the appearance of a carpet they do not affect its performance.
To discuss your concern use this form. A certified carpet inspector will contact to to discuss what you are seeing and determine if you need an inspection. There is no obligation.