🇯🇵 Japan · Building Quantity Survey Standard · Work section
Joinery, doors & windows in a Japan bill of quantities
In Japan, the joinery section of a Bill of Quantities (BoQ) (数量積算書) is measured to Building Quantity Survey Standard (BSIJ, Japan). It covers 6 principal groups of work — door frames, linings and door leaves through to staircases and balustrades — and is headed in the bill as "工事区分 3：JOINERY, DOORS & WINDOWS".
Joinery, doors & windows is one of the sections every Bill of Quantities (BoQ) (数量積算書) in Japan is built from. This page sets out what belongs in it, the unit each item is measured in under Building Quantity Survey Standard (BSIJ, Japan), the local conventions that change the quantities here, and a worked example for a 150 m² house — plus the errors in this section that actually cost money on site.
What this section covers
- Door frames, linings and door leaves
- Window frames and glazing
- Ironmongery — hinges, locks, handles, closers
- Fitted kitchen units and worktops
- Built-in wardrobes and shelving
- Staircases and balustrades
How each item is measured
| Item | Unit | Measurement rule |
|---|---|---|
| Doors and frames | no. | Enumerated by type, stating size, material, finish and handing. Priced against a door schedule, not a count. |
| Windows | no. or m² | Enumerated by type or measured on the opening area, stating glazing and opening arrangement. |
| Ironmongery | no. or set | Enumerated per door, by set. Easily 10–15% of the joinery section on a house. |
| Kitchen units | no. or m | Enumerated by unit type, or measured on the run length, stating the specification. |
| Staircase | item | A single lump sum item, fully described — flights, landings, balustrade and finish. |
Local conventions in Japan
- —Standard door size here is 900 × 2100 mm; standard window 1500 × 1200 mm, with bathroom windows around 600 × 600 mm.
- —A house of typical size here carries roughly one door per 12 m² and one window per 14 m² of floor area — a useful check against the schedule.
- —Non-standard sizes are made to order and cost disproportionately more than the size difference suggests.
Worked example — 150 m² house in Japan
Quantities for this section on a representative single-storey house, computed from Japan construction conventions. Rates are deliberately not shown: they move constantly and are priced against your own drawings.
| Description | Qty | Unit |
|---|---|---|
Doors ~1 per 12 m² of floor area | 13 | no. |
Windows ~1 per 14 m² of floor area | 11 | no. |
Lighting points 0.12/m² | 18 | no. |
Socket outlets 0.18/m² | 27 | no. |
WC suites Typical fixture count per dwelling | 2 | no. |
Wash hand basins Typical fixture count per dwelling | 2 | no. |
Septic tank & soakaway Municipal sewer is not generally available; on-site treatment assumed | 1 | item |
What goes wrong in this section
- —Ironmongery is specified vaguely and priced cheaply, then upgraded on site at full retail. Schedule it properly at bill stage.
- —Joinery lead times routinely exceed the masonry programme. A late frame order holds up plastering and therefore everything after it.
- —Enumerate from a schedule, never from an area rule, whenever a drawing exists — this is the one section where estimating from floor area is indefensible.
Get every section measured, not just this one
Upload your dimensioned drawings and get a complete bill of quantities (boq) in the Building Quantity Survey Standard format, priced in JPY (¥), with every rate source-cited.
Generate my Japan BoQJoinery, doors & windows — frequently asked
What goes into the joinery section of a bill of quantities in Japan?
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Door frames, linings and door leaves; Window frames and glazing; Ironmongery — hinges, locks, handles, closers; Fitted kitchen units and worktops; and 2 further groups of work. Under Building Quantity Survey Standard each is described, measured in its own unit, and priced separately so the total is auditable line by line.
What units is joinery, doors & windows measured in?
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Doors and frames in no., Windows in no. or m², Ironmongery in no. or set, Kitchen units in no. or m. Getting the unit right matters more than getting the quantity precisely right — a contractor can adjust a quantity, but cannot price an item measured in the wrong unit at all.
How is joinery, doors & windows different in Japan from elsewhere?
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Standard door size here is 900 × 2100 mm; standard window 1500 × 1200 mm, with bathroom windows around 600 × 600 mm.
What is the most common costly mistake in this section?
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Ironmongery is specified vaguely and priced cheaply, then upgraded on site at full retail. Schedule it properly at bill stage.
How do I get this section measured for my own project?
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Upload your dimensioned drawings to Enormous Buildings. The bill is produced in the Building Quantity Survey Standard format, grouped by section with joinery, doors & windows priced in JPY (¥), and every unit rate carries a source so a Japan quantity surveyor can check it.