In recent years, as efforts to realize a sustainable society have accelerated,there has been a growing interest inwooden construction.In addition to social demands such as the realization of a decarbonized society and the promotion of the SDGs, improvements in housing performance and advances in building technology have led to an evolution in wooden construction that has greatly overturned conventional concepts.
As INA&Associates has been involved in numerous real estate transactions, we have seena steady increase in the number of inquiries from people who are consideringwooden houses. In particular, we have received many inquiries from wealthy, environmentally conscious clients who want to know more about the merits of wooden construction and what advantages it has over other structures.
In this article, as a real estate expert,we will explain in detail thecharacteristics andspecific merits of wooden construction, as well as key points to consider when making a choice, from an objective, data-based perspective. We will strive to provide useful information for those who are considering purchasing or building a home.
Major Advantages of Wooden Construction
Economical construction cost
One of the most significant advantages ofwood constructionis its economic efficiency. Compared to steel construction (S construction) and reinforced concrete construction (RC construction), the cost of construction can be significantly reduced, which is why many builders choose wood construction.
Compared to RC construction, wood construction is generally 20% less expensive, making it a very attractive option for those who want to realize their ideal home on a limited budget.
Thiscostadvantage is due to the lightweight nature of wood. Because the building structure is light, the cost of foundation work can also be kept relatively low. Ground improvement work can be scaled down and foundations can be simplified, contributing to a reduction in overall construction costs.
Wooden construction also offers advantages in terms of maintenance and management costs. Because of the material characteristics of wood, which is easy to process, construction costs tend to be lower for future repairs and renovations compared to other structures. This is an advantage that should not be overlooked when considering long-term housing operating costs.
Environmental Performance and Sustainability
In today's society, environmental considerations have become an essential element of business and personal life.Wooden houses havea significant advantage over other structures in terms of environmental performance.
Most notable are thecarbon neutralproperties ofwood.Wood absorbs carbon dioxide from the atmosphere during its growth process and fixes it as carbon. When used as a building material, wood continues to store this carbon for the useful life of the building, which can range from several decades to over 100 years. In other words, the wooden building itself functions as a huge carbon store.
Wooden buildings also have excellent environmental impact during construction. While the manufacture of steel and concrete requires large amounts of energy and emits large amounts of carbon dioxide, the processing of wood requires relatively little energy,greatly reducing theenvironmentalimpactduring construction.
In addition, the use of wood produced under proper forest management creates a carbon cycle between forest and city. Rejuvenating forests by planting trees after harvesting enables continuous carbon sequestration, increasing the value of sustainable building materials.
Superior Habitability
The occupant performance ofwoodenhouses has characteristics optimized for Japan's climate. Wooden construction provides a comfortable living environment in the harsh climate conditions of hot and humid Japanese summers and dry winters.
In terms ofthermal insulation, wood itself has excellent properties as a heat insulator. By using wood as a structural material with low thermal conductivity, a living environment that is less susceptible to outside temperatures can be realized. This also contributes to reduced heating and cooling costs, and thus provides benefits in terms of running costs as well.
Humidity control is another major characteristic of wood construction. Wood absorbs moisture when humidity is high and releases it when it is dry. This characteristic helps maintain proper indoor humidity and inhibits the formation of condensation. Preventing the formation of mold and dust mites and maintaining a healthy living environment are important benefits, especially for allergy sufferers.
In addition, the healing effects of wood as a natural material should not be overlooked. The aroma and texture of wood have been scientifically proven to bring psychological comfort to residents and have a stress-reducing effect.
Freedom of Design and Ease of Construction
Wooden construction hasan advantage over other structures in terms of design flexibility. The workability and light weight of wood make it possible to realize complex shapes and large spaces.
The post-and-beam based axial construction method has few restrictions on the placement of walls and can flexibly accommodate future changes in floor plans. The ease with which a home can be modified to accommodate lifestyle changes is an important factor in housing that will be lived in for a long period of time.
In terms of construction, the lightweight nature of wood improves work efficiency at construction sites. The use of heavy machinery can be reduced, which is also advantageous for construction in narrow lots. In addition, wood is easy to fine-tune on site, enabling precise construction.
| Type of Structure |
Construction period (months) |
Design freedom |
Environmental Performance |
| Wooden construction |
4-6 |
High |
Excellent |
| Steel Construction |
6-8 |
Medium |
Normal |
| RC Construction |
8-12 |
Low |
Normal |
Table: Comparative data by structure (reference values)
Improved Seismic Resistance with the Latest Technology
Seismic resistancehas traditionally been pointed out as an issue forwooden buildings, but advances in modern building technology are changing this perception significantly. In particular, the development of new wood structural materials such as cross-laminated timber (CLT) has dramatically improved the earthquake resistance of wooden buildings.
CLT is a wood panel consisting of multiple wood boards laminated and bonded so that their fiber directions are orthogonal to each other. This structure provides high strength and rigidity that could not be achieved with conventional solid wood. Actual full-scale shaking table tests have confirmed that the panels exhibit sufficient seismic performance against earthquake motion exceeding the magnitude of 7.3 of the Great Hanshin-Awaji Earthquake.
Another advantage ofwooden buildings in terms ofearthquake resistancelies in their flexibility. Compared to steel or concrete, wood maintains high strength while maintaining an appropriate degree of flexibility. The flexibility of the entire building to follow the shaking of an earthquake effectively absorbs seismic energy and minimizes damage to the building.
Furthermore, the lightweight nature of wood construction reduces the inertial forces of earthquakes, thereby reducing the seismic force applied to the building itself. This characteristic is a significant advantage in seismic design, since the lighter the weight, the less force the building will be subjected to during an earthquake.
The development of the latest joining technologies has also made a significant contribution to improving the earthquake resistance of wooden buildings. In addition to conventional joints and jointing methods, metal joints and special bolting techniques have greatly improved the strength and reliability of joints. These technological innovations have made it possible to employ wooden structures in large-scale and high-rise buildings.
Diversifying Wood Construction Methods
In addition to the conventional frame construction method, a wide variety of construction methods have been developed formodernwood construction,each with different features and advantages.
Thewooden frame wall constructionmethod (2x4 construction method), introduced from North America, achieves high earthquake resistance through a box-shaped structure in which the walls, floor, and roof are integrated. The method offers stable quality and shortened construction period due to manualized lumber, design, and construction. In addition, the method excels in airtightness and heat insulation, enabling the realization of houses with high energy-saving performance.
The large-section glued laminated wood constructionmethod uses large-section glued laminated wood to achieve large spaces and large openings. It is applied to large-scale buildings such as gymnasiums and public facilities, greatly expanding the possibilities of wooden construction.
As mentioned above, theCLT constructionmethod is the latest construction method that combines high strength and workability. The panelization of the CLT construction method significantly shortens the construction period on site and ensures stable quality. It is also being applied to mid- and high-rise buildings, contributing to the spread of wooden construction in urban areas.
The diversification of these construction methods has made it possible for builders to select the most appropriate method according to their needs, site conditions, and budget. Understanding the characteristics of each construction method and making the best choice for your project is the key to a successful wooden building project.
Disadvantages of Wood Construction and Modern Measures
Commonly noted issues
This section provides a practical perspective on some of the concerns that our clients frequently discuss with us when considering awood-frame home. We would like to start by saying that many of these issues have been greatly improved by modern building technology.
Concernsregarding useful life arethe ones we hear about most frequently. Certainly, the statutory useful life of a wooden house is set at 22 years, which is shorter than the 47 years for RC construction. However, this is the depreciation period for tax purposes and differs from the actual life of the building. A wooden house with proper design, construction, and maintenance can have a durability of more than 100 years.
Sound insulation has also traditionally been considered a weakness of wooden buildings. Especially in housing complexes, propagation of sound from neighboring units has sometimes been a problem. However, modern wooden buildings can achieve sound insulation performance comparable to that of RC structures through the appropriate placement of sound insulation materials and the use of double-wall construction.
Concerns about fire resistance have also been greatly improved by technological advances. Fire-resistant designs that take advantage of the combustion characteristics of wood and the development of fireproof covering technologies have made it possible to realize wooden buildings that meet the statutory fire resistance requirements.
Solutions by Modern Technology
Modern building technology offers effective solutions to these traditional challenges.
Regarding the extension ofservice life, improvements in preservative treatment technologies have made a significant contribution. The use of boric acid preservatives and the control of moisture content in structural materials can significantly reduce wood deterioration. In addition, appropriate ventilation design can maintain the dryness of structural materials and prevent the development of decay fungi.
Regarding the improvement of sound insulation, the development of acoustic design technology has made it possible to achieve high sound insulation performance even in wooden buildings. By designing sound insulation based on the mass law and effectively arranging damping materials, it is possible to achieve sound insulation performance that meets the highest grade of the Housing Performance Indication System.
In terms of fire resistance, the superior fire resistance performance is achieved through a design method unique to wooden construction called "burn allowance design. Wood has the property of protecting the interior by carbonizing the surface, and by taking advantage of this property, the design may achieve higher fire resistance performance than steel-frame construction.
| Issue Items |
Conventional Recognition |
Improvement by modern technology |
Improvement effect |
| Service life |
22 years (legal) |
Preservative and termite-proof technology |
More than 100 years possible |
| Sound insulation |
Inferior |
Acoustic design/vibration control materials |
Equivalent to RC construction |
| Fire resistance |
Weak |
Flame-resistant design |
Meets legal standards |
| Earthquake resistance |
Insecure |
CLT/Jointing technology |
S and RC construction and above |
Table: Challenges of Wooden Construction and Improvement Effects of Modern Technology
Conclusion
Wooden constructionhas greatly increased in value as an excellent building method that meets the diverse needs of modern society. It has clear advantages over other structures in terms of economic efficiency, environmental performance, habitability, and design freedom, while modern technology provides effective solutions to conventional issues.
Of particular note isthe contribution of wooden construction to the realization of acarbon-neutralsociety. Decarbonization in the building sector is a pressing issue, and wooden construction is at the heart of the solution. For builders, it is an ideal option that can both contribute to the environment and be economical.
Whenconsidering a wooden house,we recommend that you focus on the following points. First, selecting a reliable designer and builder is of utmost importance. Working with professionals who have a deep understanding of the characteristics of wood construction and who can properly utilize the latest technology is the foundation of a successful project.
Next, planning from a long-term perspective is critical. Judgments must be made not only from the initial construction costs, but also from a comprehensive perspective, including maintenance costs, future renovation potential, and maintenance of asset value. The true value of a wooden building is most clearly revealed when it is evaluated from such a long-term perspective.
Finally, it is also essential to check local climatic conditions, laws and regulations, and subsidy programs. Wooden construction is a highly regional building technique, and its effectiveness can be maximized through planning that takes advantage of local characteristics.
INA&Associates K.K. can help you realize your ideal home with our expertise in these areas. If you have any questions or concerns about wooden construction, please feel free to contact us.
Frequently Asked Questions
Q1:Is the useful life of a wooden house really short?
A1:The legal useful life is 22 years, but this is the depreciation period for tax purposes and differs from the actual building life. With proper design, construction, and maintenance, a wooden house can have a durability of over 100 years. In fact, there are many examples of wooden houses over 100 years old that are still in use today. The key is to perform regular maintenance and appropriate renovations.
Q2:There is an image that wooden structures are vulnerable to earthquakes.
A2:Modern wooden buildingshaveexcellentearthquake resistance.The flexibility of wood effectively absorbs seismic energy, and its light weight reduces the seismic force itself. With proper structural design, it can achieve the same or better earthquake resistance performance as other structures.
Q3:Please elaborate on the environmental contribution of wooden architecture.
A3:Wooden constructionmakes a tremendous contribution to theenvironment. Wood absorbs and fixes CO2 during its growth and stores carbon for decades to more than 100 years as a building material. CO2 emissions during construction are significantly lower than other structures, contributing to the realization of a decarbonized society. Sustainable resource recycling can also be achieved through appropriate forest management.
Q4:What is the most important factor in choosing a wooden house?
A4:The most important factor is to select a designer and builder with expertise and extensive experience in wooden construction. Working with a specialist who understands the characteristics of wood and can appropriately utilize the latest technology is the key to success. Planning from a long-term perspective, taking regional characteristics into consideration, and developing appropriate maintenance plans are also important factors.