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Wanting to preserve Japan’s heavy-timber housing through the ages

By Eiji Tsushima

When I was five years old, I became strongly aware of what a “house” is. Japan had been defeated in the war, and we were living in temporary housing in Osaka. The house had been cobbled together from salvaged tin sheets, and it was cold in winter; hot in summer. During the rainy season, puddles formed inside. I felt with my body what a terrible excuse it was for a house.
However, our previous house had been burned in the air raids during the war, and we had fled to the mountains of Shikoku in Ehime prefecture. Views of the thatched villages we saw there formed a lasting image of “house”, for me.

It is about 30 years ago now that I really learned what a “minka” (heavy timber, traditionally thatched home) is. I first got hooked on minka homes when I was on a trip to the Tohoku region and saw villages full of thatched houses in various stages of disrepair. I began to travel just to see remaining thatched roofs. Then, about 21 years ago, I chanced upon thatched house in Nikko that was unoccupied, and somehow or other I got the house. Climbing up into the attic, I found the date of construction, written at the top of the main column (daikokubashira). The house was built about 200 years ago, during the Edo period.

Living in that house allowed me to appreciate thatched roofs in a much less superficial way. For one thing, it became clear to me that the saying, “thatched roof houses are warm in winter and cool in summer,” is not true. Actually, in the summer, the house was cool. Taking an afternoon nap in just shorts and a T-shirt was liable to give one a cold. But that winter, in the snowy Nikko mountains, I thought I’d freeze to death. The roof was in disrepair, so the freezing wind blew through the house. The glass of water I kept by my bed at night was often frozen by morning. Today’s ultra-air-tight housing is certainly on the other end of the spectrum from that house—I’d have to call it “ultra-air-loose” housing.

At that time it became very clear to me that living in a thatched minka house will be cold in the winter no matter what you do. People currently living in those old houses still have to deal with that hardship, which is why they so often say, “I want to tear down this old thatched house and build a new house!”

Recently, however, there has been a renewed interest in those old houses, and they have been often featured on television and in magazines. I’d like to let people know the real experience of living in such a house, including the negative side, because if we just admire those houses and don’t live in them, the minka style of building won’t last long.

What I’d like to stress, though, is that if you apply some of the construction ingenuity and experience we have gained in recent years, these houses can be quite comfortable. “Of course, but doesn’t that take a lot of money?” is the normal response. And to be honest, there are cases where refurbishing an old minka takes more money that it would cost to build a new house. So when a client comes to us with such a project, we have to carefully determine whether the house is really worth saving, and make this clear to them.

One part of this determination, though, is the reality that a treasure cannot be restored once it is broken. That is to say, an old minka takes an incredibly long time to create. First, when building a traditional minka, the builder went to the mountains and cut down some trees. After the roots and branches were removed, the log was left on the mountain to dry; it was dry enough for use after approximately 10-15 years. Wood carefully dried in this way is tough, and less likely to crack and warp. In fact, wooden beams and columns continue to increase in strength for 50 to 100 years after they have been cut down. However, in current practice, things have been considerably sped up. Lumber is air-dried (AD) only for a few months to a year. Kiln dried lumber (KD) is often used, but these days, trees are often cut down and used immediately, with no drying. So the timber in old minka houses is a very precious material that can’t be purchased with money.

Aside from the timbers, these old houses have many good points. In the summer, the thick roof provides effective insulation against the hot sun. The houses have high ceilings, with good ventilation.

However, there are in fact many aspects of minka houses that to not fit into modern life. They tend to be drafty in winter, and kitchen and bath areas, usually in the north side of the house, are usually cold and inefficient. Another point is that traditional minka homes generally have no corridors, and rooms are separated by only paper doors. This makes privacy very difficult. In addition, the threshold is generally very high, as well as the step from the clay-floored entrance into the house proper. There are no closets.

When I am reconstructing a minka house, my goal is to eliminate these inconveniences, and create a floor plan that matches the sensibilities of modern life. I want the new residents to be able to live there comfortably for decades into the future. Changing the location of kitchen and bath means an extensive remodel, but my goal is to create a great living space, rather than to preserve the house as a museum. A museum is not a convenient place to live. (That kind of work is best left to the Agency for Cultural Affairs.)

We also build new solid-wood homes, into which we try to incorporate the best aspects of minka houses, in particular the prevention of death and injury from fire. For example, we avoid the use of urethane or vinyl cloth components, or any building materials that generate toxic gasses when burning, since many times deaths from house fires occur from smoke inhalation rather than actual burns. In fact, we try to use natural materials as much as possible in our buildings, and avoid “new” building materials and petrochemical products. We remodel minka homes with the hope that they will be used for at least another hundred years. We hope this will also apply to the new houses we build.

(This article was originally published in the magazine “Ko-Minka Style”, No. 7, March 2007, in the section entitled, “Interviews with people working to connect the past with the future (Part 2; People reviving old houses)”.