Japanese tatami room - cabinetry and woodwork

February 2018

This Japanese Tatami room was designed by the owner/builders of a new passive house.  We built and installed the cabinetry and finish woodwork including the tracks for the sliding shoji doors.

Tatami are thick mats traditionally made of straw and woven rushes used as a floor covering in traditional Japanese houses.  

The cabinets and most of the finish woodwork in the tatami room were built in vertical-grain Douglas fir, to be consistent with the shoji and other finish woodwork in the house.  The cabinet sits on a plinth to raise its base to the height of the tatami.

The cabinet top is a single 15-inch wide board of Honduras Mahogany, planed and oiled to a mirror finish. 

Here's the process for dressing the rough-sawn board into the finished cabinet top by hand:

  • True the face side using a jointer plane,  winding sticks and a long straightedge
  • True the face edge with a try square and a jointer plane
  • Mark the maximum possible thickness all around with a marking gauge
  • Plane to thickness with the jointer plane
  • Final smoothing of face side & edge with a very sharp, finely-set jointer plane
  • Cut to final length and width; champher corners of front edge
  • Apply 10 coats of tung oil finish to all sides,  rubbing down face side & edge between coats with progressively finer sandpaper on a half-sheet sanding block

Details for building the door frame for the sliding shoji doors were guided primarily by Yasuo Nakahara's book Complete Japanese Joinery.  The tops and bottoms of the shoji are rabbeted to fit into grooves in the shikii  (sill) and kamoi  (head jamb).  The depth and spacing of the grooves must be carefully worked out so that the shoji can be lifted up into the deeper upper grooves and installed or removed from the lower grooves, without being too tight or too loose. 

The spacing must also be designed so that the shoji fit closely to each other, but don't hit each other when sliding.  This mockup was made to test groove depths and spacings before making the final shikii and kamoi.

The final shikii was made of sugar maple, to match the hardwood flooring in the adjacent hallway. Its thickness brings it to the height of the tatami. The kamoi is VG Douglas fir.

VG Douglas fir jamb posts were fitted at both sides of the opening. The kamoi is fastened to the jamb posts with these chiseled fastener pockets as shown in Nakahara's book.

A view into the completed Japanese Room

For more information, you can find the blog of the passive house construction project here.