Property appraisal by the Kominka Association: Individual inspections
On December 21 and 22, 2018, the Nara Kominka Association conduct the property appraisal, consisting of three inspections for: 1) basic property appraisal; 2) underfloor condition, and: 3) resistance against earthquake. Here I wrote up what I had observed.
For the Nara/ Japan Kominka Associations and the background of the inspections, please see previous post.
Observing the interview with my uncle, I learned about the history of the house. The present living and dining rooms were originally a shop and atelier of hunting rifles, established after World War II, then renovated as a residence about 50 years ago. In addition, it’s not our ancestral house. My great-grandmother had escaped from her husband for some reason, and someone saved and kept her at the house. At some stage, she acquired it.
By the way, there’s an endangered stereotype on Japanese ladies: women have no home of her own in the three worlds. In other words, women should be in subordination to parents in their childhood, to husband after marriage, then to children in their old age: after all, nowhere one can live in peace. However, as opposed to the saying, my great-grandmother achieved her own home finally.
They checked the underfloor condition of Japanese old folk houses particularly focusing on damage by termites. Termites, white ants (Don’t google it! You may come on to cringe-making pictures), are bug playing on decayed wood building materials. In contrast with stone-built houses in a cold and dry area, termites are one of the biggest perennial threats for old wooden houses in Japan with a warm humid climate. It’s said a big colony of termites can erode 25kg (33lb) of wooden materials.
Exactly how can we find the threat lurking underneath floors? That's when a robot came into play. Examiners had it crawl under the floor after taking some floorboards off. The images the robot obtained (eyesight of the robot) were projected onto a wall. We started from the living room. I didn’t know under the floors of the living room, broken tiles and stones are scattered. It must be a tough adventure for the robot: Soil surface was rugged and uneven, and some spots have a narrow gap between the ground and the floor level, difficult to slip through.
After the inspection, they checked the annex a little as a favor, though the contract covers only the main house. Apparently they make a their living by what they like. The annex was built as a tea house more than a century ago, clinging to the side of the small mountain behind our main house. They have worked with a lot of Kominka (Old Japanese folk houses), but their initial comments are: it’s uncommon that an ordinary private house has a tea house on the side of a mountain, and it survives until today.
The foundation of the building is exposed as shown in the picture below, visual observations without the robot were enough. The vestige of bark beetle was observed, and the foundation should be reinforced at an early point, if not urgently.
The seismic diagnosis of buildings constructed by a traditional construction method is to measure the imperceptible vibration itself and how it was received by buildings simultaneously. Any building structures and the ground receive imperceptible vibration at all times even without an earthquake, for example by train, home electrical appliance, and powerful wind. Possible oscillation in case of an earthquake is estimated by analyzing the data for calculating oscillation characteristics. The data is captured by using two seismic transducers/seismometers: one is on the ground, the other is put on the second floor, vertically and horizontally each other. Four-minute measurements should be repeated more than three times.
Such is the theory. In reality, the inspection of our house was done by the Kyoto branch of the federation for seismic diagnosis of buildings constructed by a traditional construction method (no formal English name found). The website is here, though no English version is available: https://kominka-taishin.org/
As our house is single-story, we ended up putting the second seismometers on the floor of the attic room. No one had stepped into there for more than 10 years, but it isn’t dilapidated, with no bad smells. Then, we started to measure the data but got a technical error. The devices are very sensitive, so a footstep within reach of the other device may skew the results. We had to stay longer to make another try.
For the Nara/ Japan Kominka Associations and the background of the inspections, please see previous post.
BASIC PROPERTY APPRAISAL
The appraisal of the house was conducted by the representative director of the Nara Kominka Association, a certified appraiser, and two younger staff members. They overhauled the condition of the main house and the annex, by checking the condition of walls and floors according to the detailed checklist, gauging the size of rooms by a laser distance meter, and interviewing with my uncle (he raised up in the house). By doing so, they would identify the existing and expected problems and suggest what should do to fix them.Observing the interview with my uncle, I learned about the history of the house. The present living and dining rooms were originally a shop and atelier of hunting rifles, established after World War II, then renovated as a residence about 50 years ago. In addition, it’s not our ancestral house. My great-grandmother had escaped from her husband for some reason, and someone saved and kept her at the house. At some stage, she acquired it.
By the way, there’s an endangered stereotype on Japanese ladies: women have no home of her own in the three worlds. In other words, women should be in subordination to parents in their childhood, to husband after marriage, then to children in their old age: after all, nowhere one can live in peace. However, as opposed to the saying, my great-grandmother achieved her own home finally.
UNDERFLOOR CONDITION
On the morning of December 22, 2018, three examiners from the Shiga branch of the Japanese association for inspection of underfloor condition (no English name), guided by the representative director of the Nara Kominka Association, arrived at the house. Shiga prefecture doesn’t have a border with Nara but located near. For the Japanese association for inspection of the underfloor condition, please see: http://kominka-yukashita.org/ (No English version)They checked the underfloor condition of Japanese old folk houses particularly focusing on damage by termites. Termites, white ants (Don’t google it! You may come on to cringe-making pictures), are bug playing on decayed wood building materials. In contrast with stone-built houses in a cold and dry area, termites are one of the biggest perennial threats for old wooden houses in Japan with a warm humid climate. It’s said a big colony of termites can erode 25kg (33lb) of wooden materials.
Exactly how can we find the threat lurking underneath floors? That's when a robot came into play. Examiners had it crawl under the floor after taking some floorboards off. The images the robot obtained (eyesight of the robot) were projected onto a wall. We started from the living room. I didn’t know under the floors of the living room, broken tiles and stones are scattered. It must be a tough adventure for the robot: Soil surface was rugged and uneven, and some spots have a narrow gap between the ground and the floor level, difficult to slip through.
Fortunately, any active nidus of termites wasn’t observed, aside from small abandoned ones. Instead, we found water leakage from a cracked pipe under the kitchen. The robot can see it but doesn’t have hands to repair it. So, as a stopgap solution, we turned off the water service of the house. The pipe should be repaired when we renovate the house.
After the inspection, they checked the annex a little as a favor, though the contract covers only the main house. Apparently they make a their living by what they like. The annex was built as a tea house more than a century ago, clinging to the side of the small mountain behind our main house. They have worked with a lot of Kominka (Old Japanese folk houses), but their initial comments are: it’s uncommon that an ordinary private house has a tea house on the side of a mountain, and it survives until today.
The foundation of the building is exposed as shown in the picture below, visual observations without the robot were enough. The vestige of bark beetle was observed, and the foundation should be reinforced at an early point, if not urgently.
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| the foundation of the annex |
RESISTANCE AGAINST EARTHQUAKE
It was a quite technical examination. As most of old Japanese houses were constructed before the Japanese Building Standards Act came into force in 1950, they often have safety problems, particularly in the resistance against earthquakes.The seismic diagnosis of buildings constructed by a traditional construction method is to measure the imperceptible vibration itself and how it was received by buildings simultaneously. Any building structures and the ground receive imperceptible vibration at all times even without an earthquake, for example by train, home electrical appliance, and powerful wind. Possible oscillation in case of an earthquake is estimated by analyzing the data for calculating oscillation characteristics. The data is captured by using two seismic transducers/seismometers: one is on the ground, the other is put on the second floor, vertically and horizontally each other. Four-minute measurements should be repeated more than three times.
Such is the theory. In reality, the inspection of our house was done by the Kyoto branch of the federation for seismic diagnosis of buildings constructed by a traditional construction method (no formal English name found). The website is here, though no English version is available: https://kominka-taishin.org/
As our house is single-story, we ended up putting the second seismometers on the floor of the attic room. No one had stepped into there for more than 10 years, but it isn’t dilapidated, with no bad smells. Then, we started to measure the data but got a technical error. The devices are very sensitive, so a footstep within reach of the other device may skew the results. We had to stay longer to make another try.
Thus, the two-day inspection was over. The director of the Nara Kominka Association told that the reports would be ready in January. For the results, see this post HERE.
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