Rug shedding: why a wool rug sheds, and how long it lasts

A wool pile rug sheds because its pile is made of cut wool, and some of the fibres in it are short. Walking, sitting and vacuuming work those short ends loose, and they gather on the surface as soft grey fluff. It is not the rug coming apart. The knots stay where they are.

It slows down. Most dealers put the heavy part at the first few months in a house, and say a hand-knotted rug settles sooner than a tufted one, because a knot grips the yarn and a tuft is only pushed through a backing. Nobody has measured this carefully for Moroccan rugs, so take the months as a guide, not a promise. A flatweave, with no pile at all, hardly sheds.

The short fibres come from the sheep and the shears. A fleece is never one even length. When a sheep is sheared, the shortest pieces, the miscuts and the locks, end up mixed in unless someone sorts them out. Where a fleece is spun by hand at home, it is not always sorted that finely. Short pieces go into the yarn with the long ones, and sooner or later they let go.

Then the knife. Once a row of knots is tied, the weaver cuts the tufts, and at the end the whole pile is trimmed level. Every cut leaves ends, and the ends drift.

There is good news inside this. Mountain wool for rugs is coarse. Carpet wool measures about 35 to 45 microns across, roughly twice the thickness of the merino in a sweater, and coarse wool wears well and pills less than fine. The fluff on the floor is the rug losing what it never needed, not what holds it together.

What helps is mostly restraint. Vacuum with suction alone, and keep the rotating brush off; a beater bar tears at the pile and pulls up more than it lifts. Go with the lie of the pile, not against it. Turn the rug now and then so the busy path to the door is not always on the same end. A pad underneath stops the rug sliding and grinding against the floor.

Museum conservators are fussier still, and their numbers explain why. In tests at the Smithsonian, a textile conservator found that suction barely changes with the motor setting, but rises sharply as the nozzle comes close to the cloth, and pressing a brush down onto a textile raised the suction about tenfold. Their advice for fragile pieces is a screen of netting between nozzle and textile, and a light hand. A sound rug is not fragile, but the lesson holds: the hand matters more than the machine.

A longer strand standing up above the pile is a different thing. That is a yarn end, called a sprout, pushed up by use. Snip it level with scissors. Do not pull it, because a pulled end can bring its neighbours with it.

A rug that keeps shedding hard after a year, or that thins in patches and shows the warp beneath, is worth a closer look. That can be worn pile, or it can be moth, and it is better to know which.

Most of the time it is only the beginning. A new rug in a new room loses its loose ends, and then it goes quiet and stays that way for a long time.