Why can't wooden houses in the United States be popularized in China because of their low cost and fast construction? Pray for the great gods.

On the application of wooden structure houses in China.

First, the issue of cost.

Unlike some people who think the wooden house is cost-effective, I think the wooden house is a black sheep. To realize the building wall with the same facade, the material cost of cement mortar and hollow brick structure is much cheaper than that of wood. To realize the above building, the labor cost of masons is also cheaper than that of carpenters, and the cost of wooden houses is about 8 times that of brick-concrete structures. In order to achieve the same fire prevention, heat preservation and sound insulation effects as brick-concrete structures, more additional technologies or materials need to be added to wooden houses. These costs are beyond the affordability of rural families who are most likely to use wooden structures in China. Although it saves time and effort to build wooden houses, China's national conditions are lack of reprocessing and finished products, and the most important thing is labor. On the other hand, to keep the wood fresh for a long time in various hot and humid environments, the maintenance cost is also a very considerable expense.

Second, the problem of durability.

In America, the history of the oldest wooden house can be traced back to the 18th century. I don't know how old the oldest brick house in China is now. As far as I know, the ancient Great Wall of Zhao Dynasty in Baotou has a history of 2300 years. "The sea is facing down and the clouds are leisurely." In fact, I don't need to pay more attention to the durability of brick-concrete structure and wood structure. Whether it is the durability of the fuselage or the enhanced durability, the durability comparison between the two is obvious.

Third, fire prevention.

If you have seen the TV pictures of the unfortunate plane crash in new york in June 1 65438+1October1,you will know that the group life in the United States is very obviously different from that in China. Take the peasant families who are most likely to use wood as an example. The distance between farmers' houses in the United States may be as far as 1 km or even farther, while the distance between wooden houses in cities is more than 50 meters. In fact, as we all know, the distance between rural houses in China is often less than 2 meters. If these houses were all made of wood, "burning camps" might happen thousands of times a year in China. 1955 65438+1October 10, an unfortunate fire broke out in the green island area of Macao, and more than 400 wooden houses were instantly burned to ashes. On July 2, 2000, a fire broke out in Tai O, Lantau Island, Hong Kong, and 65,438+040 wooden lattice houses were caught in flames. Even if the wooden house is fireproof, its fire resistance limit is limited, up to 2 hours. At the same time, wood itself is flammable. When the fire protection layer is destroyed, the wooden house structure itself will become flammable and spread to other houses, which is very different from the brick-concrete structure. Because the brick-concrete structure itself does not catch fire, even if the house catches fire, its body will not catch fire. After a general fire (except for structural damage), simple repair can restore the function of use, which is impossible for a wooden house. 1On September 2, 666, a fire broke out in London. For five consecutive days, 373 acres of land in the city were reduced to rubble, and 13200 houses were reduced to ashes. Starting from 1680, the property insurance premium of western wooden houses is twice that of brick-concrete houses. In fact, there are some things that insurance companies know better than anyone else.

Fourth, the problem of earthquake prevention.

Undeniably, because of its inherent characteristics of "using flexibility to control rigidity", wooden houses can greatly reduce the damage degree when an earthquake occurs.

The two major seismic belts in the world-the Pacific Rim seismic belt and the Mediterranean-South Asia seismic belt pass through the southeast and southwest of China respectively. Because these two seismic belts belong to the seismic belt between plates, the activity level is very high. But as far as most areas in China are concerned, it belongs to intraplate earthquake, and its activity has the characteristics of wide spread area, high frequency and high maximum magnitude. According to relevant data in China, an earthquake of magnitude 7.8 occurred in Tangshan City, Hebei Province from 65438 to 0976. The earthquake killed more than 242,000 people and seriously injured more than164,000 people. Earthquake is a great threat to human existence. It is unfortunate to have an earthquake, but if we consider wooden houses because of the earthquake, we have to say that this is not another sorrow of human science and technology. Tangshan is an industrial city with a population of 6 million (excluding floating population). If wooden houses are used and the per capita family population is 6, it is 654.38+0 million. According to the building area of each wooden house 15m x 10m, plus the common safety separation area of 50 m2 (including roads), each building needs to cover an area of 200 m2. 1 10,000 households need to cover 200 square kilometers. This living area is added with 5,800 square kilometers of cultivated land, and nearly half of the whole administrative area of Tangshan is removed,13,472 square kilometers. Can the remaining half meet the demand for industrial and commercial land? The occupied area of inapplicable land is not deducted (Tangshan is mountainous in the north and northeast, with an altitude of 300-600 meters, and coastal saline-alkali land and marshland in the south and west, with an altitude of 15 meters to 10 meters. )。 Therefore, seismic design and installation of seismic devices are mainly used to solve the seismic problem of houses, so as to develop medium-density houses and realize the compromise between large population and small land.

Verb (abbreviation for verb) air defense

In the past 200 years, the United States has basically experienced no war on its own land, while China has experienced countless wars, large and small, in the past 200 years. A modern Grenade is enough to make a wooden house collapse, but for a brick-concrete house, it can only blow up a few doors and windows at most. In fact, even an ordinary 20 mm cannon (NATO standard caliber) can easily destroy a wooden house. At present, the possibility that China is directly threatened by war still exists. The latest attack on China occurred not long ago in 1998. Of course, it does not rule out the possibility that someone threw a bomb at China that day because of a "mistake" in the navigation system or intelligence. With the fighting capacity of China's army, it may be unlikely to be attacked by the ground, but the air defense performance of buildings is a problem that cannot be ignored. It cannot be ignored that two of the seven military regions in China belong to war zones (Guangzhou War Zone and Nanjing War Zone), and armed conflicts may occur in these areas at any time.

Sixth, waterproof problem.

The most basic thing for wooden houses to resist all kinds of bad weather is waterproof. However, waterproof materials have a very real aging problem in the sun. In order to keep the house "free from rain", it is necessary to carry out regular maintenance, which is far from our understanding that the maintenance amount of brick-concrete buildings is so small. Of course, if you are very willing to DIY your house as often as Americans, that is another matter.

Seven. prevention and control of pollution

How long do you think the bright wooden house exterior wall paint will last? Besides aging and color, have you considered pollution? There are many forests in North America, and the air is fresher. Therefore, the exterior decoration can keep bright colors for a long time. But not in China, if you have been to Beijing. One day in June, 200012000, the gloomy sky suddenly appeared bright blue. The local newspaper took a color photo of this kind of sky phenomenon, which is very common in Shenzhen, and put it on the front page. If you build a white wooden house in Beijing (white is a common exterior wall color in North America), it is estimated that it will not be recognized within one month.

Eight, termite control problems

Termites are the biggest natural enemies of wood materials. Wooden houses often use barriers and overhead to solve the problem of termites, which is a very effective method in North America. So will it be acclimatized in China? It depends on the source of termites. There are two ways for termites to enter the house: one is invasive, that is, they enter the house directly. The other is parasitism, that is, entering the house through other wooden furniture. Invasive is easy to prevent, but parasitic is a bit difficult. Because not every wood factory in China is treated by ants when producing furniture. To be completely sure that there is no problem, you may have to buy a whole set of furniture imported from North America when you buy a wooden house.

In addition to the above basic problems, let's try to consider them from other aspects:

First, wooden houses can't improve people's living standards.

In addition to the inherent advantages of spending more money on brick-concrete buildings, wooden houses have only "exotic customs". Imagine that it is really interesting to build an American wooden house among many traditional buildings, but I can't find a second reason to support the choice of wooden house. Functionally, it didn't bring anything extra. On the contrary, more than 8 times of investment will inevitably reduce investment in other fields, which is not conducive to improving people's quality of life.

Second, the wooden house does not conform to the national conditions of China.

China has a vast territory and rich resources, which is a word we often hear when reading geography. Let's look at a comparison: the United States has a land area of 9.37 million square kilometers and a population of 270 million (1998 data), while China has a land area of 9.6 million square kilometers and a population of12.4 billion (1998 data). China not only has a small per capita area, but also has too many uninhabitable terrains. It is a very realistic fact in China that there are many people and few people. It is not feasible to develop ultra-low density houses such as wooden houses in China.

Third, China is a Shaolin country.

The existing forest area in China is1.300 million hectares, accounting for only 3% ~ 4% of the world forest area, and the forest coverage rate is less than 1.4%. The per capita forest area is only 0. 1. 1 hectare, and the shrub stock is 860 million cubic meters, which are only equivalent to the world average of 1.7% respectively. Imagine if China people need to import cement and sand from another country to build their houses. It's definitely not a good idea to buy this kind of thing with foreign exchange.

Fourth, wooden houses have no advantage in construction speed. Source: Examination University

Maybe we have all heard some opinions that the construction time of wooden houses is very short. In fact, wooden houses don't have much advantage in construction speed. Building a house with modular prefabricated cement components is equally fast, and may even be faster than a wooden house. And all the materials of cement prefabricated parts can be solved locally in China. Cement precast units can be used not only for single-storey houses, but also for medium-high-rise houses, thus developing medium-density houses. This is an ideal solution. The industrial production cost of cement prefabricated parts is very low.

Fifth, wooden houses are not "advanced"

Because western developed countries adopt wooden houses, does that mean that wooden houses are "advanced" things? I don't think so. Just like some people in China forcibly promote the open kitchen, the first point is that it does not conform to the domestic cooking habits. When the oil fume escapes everywhere in the house, will you be complacent because of the open kitchen? . Why do North American countries like to use wooden houses? This has nothing to do with being advanced. Most of the early North America was virgin forest. Later, Europeans immigrated here to mine forests and build wooden houses. Because of the abundant wood and vast land, immigrants used wooden structures to build houses according to local materials. In modern times, with the increase of population and the shortage of land, people begin to build group houses and apartments in urban and suburban areas, and the number of floors is getting higher and higher. In other words, North American residents used wooden houses in the early days because of local conditions. Nowadays, it is an inevitable trend to build multi-storey houses.

In my opinion, wooden houses may be an option for high-income villas or resorts, which depends entirely on the architectural style of the community. But if it is promoted as a national project, there is really no sufficient reason.