Translation guide
A horizontal structural member used in framing to support a floor or ceiling. In Japanese, this is typically expressed with specific architectural terms depending on the context.
A horizontal beam that supports the floorboards and distributes the load to the main beams or walls.
The standard term for floor joists in Japanese construction. These are smaller beams laid across larger beams (大引) to support flooring.
根太の間隔は30センチです。
The joist spacing is 30 centimeters.
Fix the joists onto the floor beams.
Explicitly 'floor joist', used when distinction from ceiling joists is needed.
The floor joists are rotten.
A horizontal beam that supports the ceiling finish and may also tie the walls together.
Specifically refers to ceiling joists. In traditional Japanese architecture, these are often visible and decorative.
Put insulation between the ceiling joists.
Lightweight ceiling joists or furring strips used to attach ceiling boards. Common in modern drywall or traditional wood ceilings.
A generic term for a horizontal structural member, not necessarily floor or ceiling specific.
A general term for a horizontal beam. Can be used for joists in a broader sense, but less specific than 根太.
Support the floor with horizontal beams.
A secondary beam that spans between main beams, similar to a joist in function. More common in steel or large timber structures.
Lay the deck plate on the secondary beams.
The English word 'joist' does not have a single perfect equivalent in Japanese. The correct term depends on whether it is for a floor (根太), ceiling (天井根太), or a general horizontal member. Using the wrong term can cause confusion in construction contexts.
In traditional Japanese wooden floor framing, 大引 (おおびき) are the larger main beams, while 根太 (ねだ) are the smaller joists laid across them. This is similar to the distinction between 'girder' and 'joist' in English.
Lay the joists across the girders.
After installing the ceiling joists, attach the drywall.