The foundation is normally cotton with a wool pile in most cases. The popularity of Tabriz rugs dictates that all ranges of sizes, shapes, qualities and materials will be used. However, in general a good Tabriz rug will be of a high standard, medium to large in size and made with fine, soft wool. [ref. Dr Reza Cheshmehdoost]
Placing the correct size rug in your space is as important as choosing the right color or pattern. A rug that it is too small will shift the balance of the room unfavorably. A rug that is too big, especially in open floor plans, may put the area designations off. There are a few rules of thumb, but a picture says it better. Use these handy guides by Interior Designer Lisa Ferguson to make the best choice.