Knotted pile refers to the construction method that gives a traditional Oriental rug its dense, plush surface. The technique requires a weaver to tie individual knots — one at a time — around the vertical warp threads stretched on a loom. After each row of knots is tied, one or more horizontal weft threads are passed through and beaten down tightly, locking the knots in place. The ends of each knot stand up to form the pile, which is then sheared to a uniform height.
A knotted-pile rug is typically made of:
- Foundation — the cotton, wool, or silk warps and wefts that form the rug's underlying structure
- Pile — the wool or silk yarn that is knotted and trimmed to form the visible surface
- Selvedges — the reinforced left and right edges
- Fringe — the warp threads that extend beyond the top and bottom ends
The two main knot types used are the asymmetric (Persian) and symmetric (Turkish) knots. A skilled weaver typically ties 6,000 to 10,000 knots per day; finer city-workshop weavers may tie fewer at higher density. A large, finely knotted carpet can represent several years of work by one or more weavers.
Knotted-pile rugs stand in contrast to flatweaves such as kilims and soumaks, which have no pile and are woven by interlacing threads rather than tying knots.