Warp and weft

Two sets of threads

The warp threads are stretched tight on the loom from top to bottom before weaving starts. They run the full length of the rug.

The weft threads pass over and under the warps from side to side. In a pile rug, the weaver ties a row of knots around the warps, then beats one or more wefts down on top of the row to lock it in place. The warps and wefts together are called the foundation.

What they are made of

Most rug foundations are cotton or wool. Cotton is strong and stretches little, so it holds the tension of the loom well and helps a rug lie flat and square. Many city and workshop rugs use it.

Wool foundations are common in village and tribal rugs, where weavers used the wool of their own flocks. A few very fine rugs, mostly Persian, are woven on silk.

The fringe is the warp

On a hand-knotted rug the fringe is not added. It is the ends of the warp threads, left loose or knotted where the rug was cut from the loom. That is why fringe sits only on the two short ends.

On many machine-made and hand-tufted rugs, the fringe is sewn or glued on after the rug is made. If you fold back the end and see a strip of fringe stitched to the rug, it was added.

Reading the back

Turn a hand-knotted rug over and you see every knot, with the weft running between the rows. The pattern shows on the back almost as clearly as on the front.

A hand-tufted rug has a cloth backing glued over the back, which hides the foundation. A machine-made rug shows a very even grid, often with the same small lines repeating across the whole back.

Warps and knot count

Each pile knot wraps around two warps. The more warps per inch, the more knots fit in a row, so a fine rug starts with closely spaced, thin warps.

In many Persian city rugs, one warp of each pair sits lower than the other. This is called a depressed warp. It packs the knots tighter and makes the rug firmer and less floppy.

Flatweaves show the weft

A kilim has no pile. Its colored wefts are packed tightly over the warps and form the whole design, so the warps are hidden. Weavers call this weft-faced weaving.

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