The composition of materials plays an important role in the building as a whole and is the way in which architects express their artistic intentions. In recent years, the term "green building materials" or "building skins" has become a common term in the field of architecture, bringing some influence to architects in the design process. This article attempts to explore the connection between green building materials and building skins in order to help architects.

　　1 Green Building Materials Concept

　　Green building materials can be simply called green building materials, or environmentally friendly building materials. The relevant materials research association has proposed the meaning of “green materials”, and the international academic community has unified the meaning of green materials, which is through the use of raw material extraction, product processing and production, the use of links and after use can be reused and other processes, and cause little harm to the environment and will not bring adverse effects to human health.

　　Regarding the explanation of green building materials, China held the first conference on the development direction of green building materials in 1999, thus clearly stating that green building materials are produced by using clean production methods, using less natural resources, and using industrial and agricultural wastes that are not toxic, not polluting, not containing radiation, and can be reused after the use time to maintain The ecological balance and health safety of our country.

　　Generally speaking, there are major differences between green building materials and traditional building materials, which are reflected in the following aspects.

First, the reduction of waste of natural resources and the rational use of production materials.

Second, the use of technologies that reduce energy consumption to produce as well as technologies that do not cause damage to the environment.

Third, the production without the addition of formaldehyde and other harmful substances.

Fourth, the products are designed to be implemented on the basis of protecting people’s health and safety as well as not damaging the environment, which is what people call not only not causing harm to human health, but also benefiting human health. Products have different functions, such as: can prevent germs, fire prevention and other multifaceted advantages.

Fifth, in line with the requirements of sustainable development in China, for secondary use, to maintain the balance of the ecological environment.

　　There are various kinds of green building materials, which not only have traditional materials, but also have new materials. Although the meaning of green building materials has been unified for a long time, it is difficult for architects to design in accordance with quantitative standards. Green Building Materials Green building materials play an important role in the economic development of China and have become the main direction of building materials development.

　　2 Building skin

　　Usually, the building skin mainly contains the overall building envelope, which does not include the roof. However, under certain specified conditions, such as a specified geometric shape, it is possible to see that the roof and the surface are effectively combined, making it difficult to distinguish between them, or that the roof is designed as a “fifth façade” in order to improve the viewing angle, which can also be used as a component of the skin.

　　3 Green building materials in the design of the building skin of the artistic expression

　　As the slogan of “low carbon and environmental protection” advocated by China has been widely responded to, the adoption of green building materials in the process of building skin design has an important impact on the development of the design. This article is a compilation of outstanding examples in recent years, so as to provide architects with mutual learning and exchange, for reference only.

　　3.1 Combination of multiple materials

　　The effective combination of different types of materials is common in the process of skin design. Because different kinds of materials will give the effect of layering, colorful, and bring different feelings of vision. Therefore, the combination of different materials will bring a strong sense of impact. However, this does not mean that materials can be matched in any way, nor does it mean that using a large number of materials on the same building is better. Architects must be in the pre-design stage, should be the overall characteristics of the material, whether the surrounding situation is consistent, the design theme is consistent, which have taken into account these elements to achieve the desired effect.

　　For example, the Tengtou Pavilion in Shanghai World Expo 2010, in terms of materials used bamboo, old bricks, old tiles, concrete and other materials, concrete is mainly burdened with the needs of structural load-bearing, bamboo, old bricks, old tiles reflect the principle of reuse and recycling of materials, these materials have different textures and set off each other, forming a unique architectural appearance.

　　3.2 Expression of green building materials’ detailed emotion

　　Detail design shows the perfection of the surface skin form, which integrates different materials and finishes, reflecting the way of intersection of different materials and structures between the surface and the surface, between the local and the whole, and this intersection brings the intersection of the surface skin color, material and texture. Just as language has emotion, detailing in the building skin reflects various expressions. In the skin design, a lot of time is needed to study the node design of material intersection, which is not only a technical requirement, but also the pursuit of formality. For example, the skin design of Beijing National Centre for the Performing Arts (NCPA), the simple skin of the building has a lot of carefully designed details, which is full of connotation in the atmosphere. The detailed design can reflect the sense of scale of the building, express the relationship between different components, enrich people’s visual experience, and express the deep regional cultural connotation.

　　The exterior wall of Tengtou Hall is a frequent architectural skin treatment by Chinese architect Wang Shu. Through the ingenious combination of these old bricks and tiles, he turns the decay into magic, forming a unique form of architectural skin and rich detailing, and at the same time, he can read the traditional craftsmanship of local craftsmen and the way of using materials, so that people can experience the continuity of regional culture. People experience the continuity of regional culture and stimulate people’s nostalgic feelings.

　　3.3 Expression of materials by light

　　Different materials will show different effects even under the same light due to their different textures and colors. Materials with rough surface, such as wood, brick, stone, concrete, etc., can make light uniform and soft due to diffuse reflection of light, forming a homogeneous sense of space atmosphere. For the smooth surface materials, such as glass, polished marble, smooth metal, etc., due to its strong reflectivity, often produce stronger reflections under the light, forming a visual impact, invigorating. Different light conditions can affect the expression of material texture and color.

　　As a response to the requirements of low carbon and environmental protection, how to produce energy and sequester carbon in buildings has become an important issue. The building skin, as the outer envelope of the building, is the interface in direct contact with the sun, so the use of solar materials as much as possible has undoubtedly become an important means of building energy production, and at the same time, by setting up greenery on the building skin can absorb part of the CO2 and help achieve carbon reduction. In the skin design of the Alsace Pavilion at the Shanghai World Expo, solar photovoltaic cells and greenery on the walls become important components of the building skin. Finally, in addition to natural light, artificial light also has an important expressive power, and the effect of the building skin under artificial light is also one of the elements worth considering.

　　Conclusion

　　In the process of architectural theory, the main concept of building design is still carried out in two aspects: architectural form and spatial design. However, we appreciate more deeply the creation of art by architects. China’s development is inseparable from the environment and resources, and the times demand that China not only achieve the effect of architectural beauty but also meet the needs of sustainable development. Therefore, we can effectively combine green building materials and skin to promote the development of low carbon and environmental protection. This article makes a relevant summary on this basis, and the system can bring inspiration to architects and contribute to the development of social economy.