Cast-Iron Bathtub Weights and a Visit to the Reopened KOHLER Tokyo Showroom
Compare two documented cast-iron bathtub weights and plan a reservation at KOHLER’s reopened Tokyo showroom, with access details and delivery checks.
Reserve before visiting Takanawa
KOHLER announced its renovated Tokyo showroom on August 21, 2026. The no-reservation reopening days were September 4 and 5, and visits from September 7 onward were announced as reservation-only (official KOHLER renovation announcement).
The announcement says the showroom displays bathtubs generally, but it does not identify either catalogue model or confirm that any cast-iron bathtub is currently displayed. Before travelling, send the exact model number and ask whether it is currently sold in Japan, available to inspect and within the showroom’s consultation scope. Use the local distributor’s showroom page for access details and the appointment form to request a visit.
The showroom is at Ono Takanawa Building 1F, 2-21-38 Takanawa, Minato-ku, Tokyo. Listed rail approaches are approximately:
- 2 minutes from Sengakuji Station, A2 exit;
- 6 minutes from Takanawa Gateway Station; or
- 9 minutes from Shinagawa Station, Takanawa exit.
Listed hours are 10:00–12:00 and 13:00–17:00. The listed closures include Sundays, public holidays and seasonal holidays, and no customer parking is provided. Confirm the current hours and reservation when booking; these practical details are published on the local distributor’s showroom page.
The short answer: documented models weigh 113–119 kg
KOHLER Japan’s catalogue documents two cast-iron enamel drop-in tubs with listed weights of 113 kg and 119 kg. These are examples for named models, not a universal weight range for cast-iron bathtubs.
The following specifications appear on printed page 137—PDF page 70—of the KOHLER 2025–2026 product catalogue.
| Model | Type and dimensions | Capacity | Listed weight |
|---|---|---|---|
| TEA-FOR-TWO K-863T-0 | Drop-in; 1,829 × 914 × 530 mm | 337 L | 113 kg |
| REPOS K-18200T-GR-0 | Drop-in; 1,600 × 750 × 460 mm | 176 L | 119 kg |
REPOS has smaller dimensions and lower capacity, yet its listed weight is 6 kg higher. Start with the specification for the exact model rather than a generic estimate or a visual comparison.
Use listed weight or product weight carefully. The catalogue presents weight separately from capacity, but it does not explicitly define the figure as empty, net, packaged or shipping weight. Ask the supplier to define it and provide the packaged dimensions and mass needed for delivery planning.
What cast-iron enamel means—and what the weight figure leaves out
The Japanese term imono hōrō (鋳物ホーロー) refers to a sturdy cast-iron base coated with a glass-enamel layer, according to LIXIL’s glossary definition. This describes the material construction; it does not determine what a particular bathtub weighs.
The complete installed load is a key planning figure for the finished bathroom, but it cannot be calculated accurately from a catalogue entry alone.
Even the total installed mass is not, by itself, a structural decision. Do not use the material type, external dimensions or water capacity as substitutes for that assessment.
A transparent way to estimate the in-use load
Calculate the two relevant stages separately:
Anticipated in-use mass = listed product mass + actual water mass + bather mass
Complete installed load = anticipated in-use mass + supports and known construction materials
For preliminary planning, one litre of water contributes approximately one kilogram of mass. The relevant input is the water expected at the intended fill level—not automatically the tub’s rated capacity. Normal bathing level may be lower, and a bather displaces some water.
Using the catalogue capacities produces two transparent full-capacity illustrations:
- TEA-FOR-TWO: 113 kg product weight + 337 L of water ≈ 450 kg
- REPOS: 119 kg product weight + 176 L of water ≈ 295 kg
The water conversion and these sums are preliminary arithmetic; the product weights and capacities come from KOHLER’s catalogue. They cover only the listed product weight and water at full rated capacity. They exclude the bather, supports, surround, fittings, waterproofing and finishes. They are not normal-use totals, complete installed loads or evidence that a floor can support either bathtub.
Map the entire delivery route through the Tokyo property
A tub can fit the bathroom plan and still fail at the building entrance, elevator, staircase or final turn. For a Tokyo apartment or house, trace the route from the proposed unloading point to the installed position before ordering.
| Route checkpoint | What to record |
|---|---|
| Loading point and entrance | Clear width and height, kerbs, steps, canopy and questions about stopping or unloading arrangements |
| Elevator | Door and cabin dimensions, load limit, reservation process and protection rules |
| Corridors and corners | Clear width, turning space, handles, wall projections and fixed cabinets |
| Stairs and landings | Width, headroom, railings, turns and landing dimensions |
| Bathroom doorway | Clear opening after accounting for the door, handle and trim |
| Final position | Approach angle, working clearance and space for the specified support assembly |
Measure clear usable dimensions, not nominal openings. Photograph fixed obstacles and record low ceilings, railings, handles, level changes and tight turns. Compare the route with the packaged dimensions for the exact model, not only the bare bathtub dimensions in the catalogue.
For a condominium, ask the building manager or management association about the property’s renovation application, loading reservations, elevator procedures, protective coverings, permitted work hours and contractor requirements. For a house, ask the logistics provider to review the proposed stopping and unloading arrangement, narrow approaches and internal stairs. These are property-specific questions; no single management procedure applies to every Tokyo building.
Bring one practical brief to the appointment
Send the exact model number, bathroom plan and proposed floor level when booking. Include the entrance, elevator, corridor, stair and doorway measurements, together with the building’s renovation requirements. Ask for current Japanese specifications, installation drawings, support requirements and packaged dimensions and mass.
The showroom can help with product selection and documentation. Give those documents to the installer and designer responsible for the property; floor capacity and any reinforcement questions need an appropriately qualified structural professional. Agree who will survey the delivery route, coordinate building approval and arrange unloading before ordering. The catalogue weight alone cannot establish whether the proposed installation is suitable.