Straw Mat Used in Japanese Homes as a Floor Covering

Size

• Tatami mats come in standard sizes, which vary by region. Those from Kyoto are the largest, followed by those from Nagoya and finally those from Tokyo. The dimensions of a room are usually stated in terms of the number of tatami mats it takes to fill it. In Nagoya, where tatami dimensions are measured using the English system of measurement, a 4-1/2-mat room is 9 feet by 9 feet. The thickness of a tatami mat is typically about 2-1/4 inches, although this also can vary somewhat from region to region.

Features

• The core of a tatami mat, made of compressed material, gives the mat a firm flexibility that makes it comfortable for sitting and lying upon. Its insulation value is sufficiently high that tatami mats are used to form the main barrier between the ground and the living space in Japanese houses. The straw lends a pleasant fragrance to the room, especially when the mats are new, and the fine weave of the surface straw, together with the delicately brocaded edges of the mats, gives the room an elegantly naturalistic appeal that is typically Japanese.

Disadvantages

• Japanese people take up their tatami and air them out periodically because the core is a breeding ground for mold, especially in the summer when the humidity is high. Mold that grows in the core eventually spreads to the surface, discoloring it and creating a toxic environment in the room. Manufacturing the core with polystyrene plastic mitigates this problem somewhat. Small tatami mites also find the core an attractive nesting place. Called "dani" in Japanese, they can deliver painful bites to anyone sitting or sleeping on the mats. Controlling them can be difficult and sometimes requires an insecticide.

Considerations

• You must take into account the thickness of traditional tatami if you plan on using them in a room that isn't designed for them. Japanese floors are constructed to accommodate tatami mats, but if you want to lay them on top of an existing floor, you usually have to construct a frame to hold them together, and then design the doorways and cabinets to account for the extra height. Some flooring dealers offer single layers of woven straw matting as a substitute for real tatami mats. It gives the same visual impression, but only some of the tactile benefits.