How to Replace Tatami Mats: A Landlord’s Guide
Tatami mats are one of the most distinctively Japanese elements of a rental property, and they’re also one of the maintenance items that surprises foreign landlords with their specific care requirements and replacement schedules. After years of managing properties with tatami rooms (u548cu5ba4), I’ve developed a system for evaluating tatami condition, deciding between surface replacement and full mat replacement, and handling the work efficiently to minimize vacancy time between tenants.
Understanding Tatami Structure
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A tatami mat has three layers: the core (u5e8a / u3068u3053), traditionally made from compressed rice straw (u308fu3089) but now increasingly from polystyrene foam or wood chip board (u5efau6750u7573u5e8a); the padding layer (u7573u5e8a); and the surface rush weave (u7573u8868 / u305fu305fu307fu304au3082u3066) made from woven igusa (u30a4u30b0u30b5) grass. Running along the edges is the border fabric (u7573u7e01 / u305fu305fu307fu3078u308a), typically a dark brocade in residential settings.
Knowing this structure matters because replacement options differ. Ura-gaeshi (u88cfu8fd4u3057) flips the existing rush surface for renewed use u2014 only possible when the surface is relatively new. Omote-gae (u8868u66ffu3048) replaces the rush surface on the existing core. Full replacement (u65b0u8abf / u3057u3093u3061u3087u3046) replaces the entire mat. Each option has different costs and appropriate conditions.
Evaluating Tatami Condition
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Assess tatami condition by looking for: severe discoloration or staining that won’t clean up; soft spots indicating core damage or moisture rot; strong mildew odor coming from below the surface; broken or fraying rush weave; insect damage (check for small holes or sawdust-like debris indicating u7573u866b). Surface yellowing and minor fading are normal aging u2014 igusa naturally turns from green to golden brown u2014 and not necessarily a cause for replacement.
A healthy tatami surface has intact, firm rush weaving with a slight sheen. Push down firmly across the surface u2014 it should feel uniformly dense. Soft spots or areas that give differently indicate core damage. Lift a mat slightly at one corner to check the underside for moisture staining or mold, which appears as dark spots or a grayish bloom on the straw.
DIY Tatami Removal and Replacement
Tatami mats can be removed without tools in most cases. They sit in a shallow wooden frame (u7573u6846) and are simply lifted out. In a standard Japanese room, one mat is always the “starter” mat that lifts freely u2014 it has a small gap or slight looseness at one edge. Use a flat tool like a butter knife or thin shim to pry up the starter mat, then lift and carry each subsequent mat out of the room.
Carry mats on their side, not flat u2014 they’re heavy (typically 25u201340 kg for straw core mats) and carrying flat puts stress on the rush surface. Stack removed mats outside the room to allow ventilation. Sweep and vacuum the subfloor (u7573u5e8a) thoroughly before new mats go in u2014 this is also a good time to inspect for termites or moisture damage in the floor joists beneath.
For actual surface replacement (u8868u66ffu3048) or new mats (u65b0u8abf), I strongly recommend using a tatami shop (u7573u5e97) rather than doing the weaving work yourself u2014 it requires specialized equipment. What you can do yourself is the removal, subfloor prep, and reinstallation of the repaired mats. Tatami shops typically offer pickup and delivery, charging 3,000u20138,000 yen per mat for surface replacement depending on the grade of igusa used.
Tatami Sizing and Ordering in Japan
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Japanese rooms are sized by tatami mat dimensions, but frustratingly, tatami mat sizes vary by region. The main standards are Kyoma (u4eacu9593) at 955 u00d7 1910 mm, Edoma or Kantoma (u6c5fu6238u9593) at 880 u00d7 1760 mm, and Chukyoma (u4e2du4eacu9593) at 910 u00d7 1820 mm. Measure your existing mats accurately before ordering replacements u2014 a 3 mm error means gaps or mats that won’t fit. When in doubt, give the tatami shop the room’s actual floor dimensions and let them cut to size.
New igusa tatami surfaces (u65b0u5e8a) have a fresh grassy smell and bright green color that fades naturally over the first few months. This is considered a feature, not a defect. Inform new tenants of this u2014 some are surprised by the color change. Avoid exposing new tatami to direct sunlight during the first weeks to reduce uneven fading. Tatami rooms should be aired out regularly by opening windows; sustained humidity is the main enemy of tatami longevity.
Maintenance Tips to Extend Tatami Life
Instruct tenants to vacuum tatami along the weave direction (not across it) and to avoid letting water sit on the surface. Furniture placed on tatami should use felt pads to prevent crushing the rush weave. Air the room out thoroughly at least twice a year u2014 in spring and fall u2014 by removing mats and standing them against a wall outdoors (in a shaded, breezy spot) for a few hours. With proper care, quality tatami surfaces last 10u201315 years before needing replacement.
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