Can I have a hinoki soaking tub in my Tokyo condo, and how do I care for it?

What a Japanese soaking tub is

A Japanese soaking tub, or ofuro (the home bath), is deep and short. You wash and rinse outside the tub, usually seated on a low stool, and then sit in clean hot water up to the shoulders. The water is for warming and resting, which is why the bathroom in a Japanese home has a washing area with its own floor drain beside the tub.

Many Tokyo condominiums already have a deep tub of this kind in a prefabricated unit bath, with walls, floor and tub made as one waterproof shell. The question owners ask is usually about material: whether that tub can be wood.

Hinoki and the other bath woods

Hinoki (Japanese cypress) is the wood most associated with Japanese baths. Shimizu Mokuzai, a wooden bath maker in the Kiso area of Nagano, describes it as the classic material for wooden baths. The same maker lists three other woods used for tubs: koyamaki, described as highly resistant to water and decay; Aomori hiba, noted for the compound hinokitiol; and sawara, which is light and water-resistant.

Most of the pleasure of a hinoki tub is its scent and the feel of warm wood. That scent comes from the wood itself, so it is strongest when the tub is new and in use.

Condo bathrooms: what to know and ask

Replacing a bath in a condominium involves waterproofing and drainage, which connect to the building's common elements. Under Article 17 of the national Standard Condominium Management Bylaws (English provisional translation, April 2026), an owner who plans work that may affect common elements must apply to the association with drawings, specifications and a work schedule, and obtain approval in advance. Even work that does not need approval may require notice for contractors' access, deliveries and noise. Your building's own bylaws and detailed rules decide what is allowed.

The work itself is for a licensed contractor. Under the Construction Business Act, contractors who take on interior work of 5 million yen or more per job need a construction business licence. STAYGO ATELIER does not carry out or manage building work.

Before choosing a tub, these are useful questions:

• For the management company: do the bylaws allow replacing the bath, what must the application include, which days and hours is work permitted, and are there rules on floor load or waterproofing.
• For a licensed contractor: can a wooden tub sit within the existing unit bath, or does it need a half-unit bath, where only the lower part is a prefabricated waterproof shell, or a full rebuild; where do the drain and supply run; how will the tub and materials come up through the building.
• For the tub maker: the size and weight when full, the treatment applied at the workshop, and written care and absence instructions in English.

Daily care and drying

Shimizu Mokuzai's care guide asks owners to drain the water after every use and not to leave hot water standing, which leaves a gelatinous film inside. Clean marked areas straight away with a soft sponge, wipe off the remaining water with a dry cloth, ventilate the bathroom well and let the tub dry naturally, without over-drying it.

The maker treats the wood with a water-repellent, anti-mould protective agent before delivery. Its effect lasts about six months, so it should be reapplied every six months to a year, and the tub should not be used for 24 hours afterwards. With regular care, the maker gives about 15 years as a guide to replacement, noting this is not a guarantee.

In the maker's 2026 guide, direct sunlight is named as a cause of cracking, and emptying the tub every few days to let it dry fully is advised.

The empty-home problem

A part-time home pulls a wooden tub in two directions. The Tokyo Metropolitan Government's fiscal 2016 survey found the bathroom was where mould appeared most often, in 79.7 percent of households that had seen mould. A hinoki tub left damp in a closed bathroom through a Tokyo summer is at risk.

Too dry is also a problem. Shimizu Mokuzai warns that a tub not used for more than two weeks, or kept in a room with bathroom or floor heating, can dry out and crack. Its advice is to place a bucket of water inside the tub and close the lid.

If you are away for months at a time, ask the maker for its absence instructions before ordering, and ask whoever checks the home to follow them: lid on, water in the bucket, fan running, no direct sun. If that is not realistic, a smaller piece of hinoki may suit the home better.

Free-standing tubs and smaller hinoki pieces

Some makers produce free-standing hinoki tubs. These avoid rebuilding the bathroom, but they still need a waterproof floor, a drain, a way to fill them and a floor that can carry the weight of the tub when full. Ask the management company and a licensed contractor before ordering one.

Hinoki can also come into the bath in smaller forms that need no building work: a bath stool, a washing bucket, a slatted mat for the washing area, or a lid for the existing tub. They bring the scent and the feel of the wood, and they can be dried in the open air and stored when you leave.