Green Home Building and Sustainable Architecture

Sustainable architecture is an exciting and important field, with many people reviving traditional methods of building and others creating innovations to established practices. Kelly Hart, webmaster of the popular website www.greenhomebuilding.com, posts text and photos featuring what he discovers from around the world.

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Location: Crestone, Colorado, United States

Kelly Hart has been involved with green building concepts for much of his life. He has also worked in various fields of communication media, including still photography, cinematography, animation, video production and now website development. Kelly has lived in an earthbag/papercrete home that he built and consults about sustainable building design.

July 27, 2008

Tulou Chinese Architecture

I received an email from Professor Sunny Cai, who teaches architectural design at a college in Beijing , China. He mentioned his interest in ancient Chinese architecture, especially the earthen buildings called “tulou,” and he sent me some pictures of these rammed earth buildings.

I had never seen anything quite like them, so I queried him further about how they were made and used. He replied, “The foundation was built with rocks, 2 feet high all around. The juice of glutinous rice and some lime is mixed into the earth for strength, and then sliced bamboo, reeds, and sometimes pieces of wood are also used.”

This picture was taken in front of a rammed earth building with Sunny Cai and his students.

I did some further internet research and found out more about these interesting structures. Tulou are traditional communal residences in the Fujian province of Southern China, often of a circular configuration surrounding a central shrine. Some of these vernacular structures were constructed of cut granite or had substantial walls of fired brick. The end result is a well lit, well-ventilated, windproof, earthquake resistant building that is warm in winter and cool in summer.

There are more than 20,000 tulou in southern Fujian, and these were designated as a UNESCO World Heritage site in 2008 as “exceptional examples of a building tradition and function exemplifying a particular type of communal living and defensive organization, and, in terms of their harmonious relationship with their environment".

Actually the Tulou were built by a minority called the Hakka, who were originally Han who fled south to escape war and famine during the Qin Dynasty (221-206 BC). As they gradually moved they changed the local architecture by incorporating Han styles and that produced the tulou. Not only were the high walls built for defense but they were also the result of traditional Han architecture. Tulou were mostly built between the 12th to the 20th centuries. The oldest one was constructed over 1,200 years ago and is regarded as a “living fossil” of the construction style of central China.

There are three types of Tulou. The Wufeng has three halls and two side rooms and are said to be the result of a redesign of the Han courtyard. The oldest tulou are the rectangle ones, and the most emblematic ones are round. They are typically designed for defensive purposes and consist of one entrance and no windows at ground level. The biggest round one can have up to five stories with three interior rings. The largest houses cover over 40,000 m² and it is not unusual to find surviving houses of over 10,000 m². Most round tulous are three or four stories, with family kitchens and livestock on the ground floor. The next floor becomes a storage room for food and furniture (with no windows), and above that are the bedrooms.

These structures are exemplary of sustainable architecture in that they are built of local, natural materials with simple techniques. They have good thermal attributes, with the massive earthen walls to help buffer temperatures. They are obviously built to last, and house many of the necessities for life. And they embody a communal life style that conserves energy and resources; these represent a form of ancient co-housing.

July 22, 2008

California's Green Building Code

California has adopted the nation's first statewide green-building standards, which will become mandatory in 2010. The new California Green Buildings Standards Code requires builders to reduce energy use by 15 to 30 percent beyond current standards and use more recycled materials. Some of the code will be mandatory, while other parts are just suggested. This is a significant recognition that energy and resource conservation is essential for the welfare of state residents, and hopefully this officially sanctioned consciousness will spread to other states.

These new codes include basic passive solar mandates: "When site and location permit, orient the building with the long sides facing north and south. Provide exterior shade for south-facing windows during the peak cooling season. Provide vertical shading against direct solar gain and glare due to low altitude sun angles for east- and west-facing windows."

For renewable energy, the codes says, "Use on-site renewable energy sources such as solar, wind, geothermal, low-impact hydro, biomass and bio-gas for at least 1% of the electric power."

For water conservation, the code says, "A schedule of plumbing fixtures and fixture fittings will reduce the overall use of potable water within the building by 20%, and provide water efficient landscape irrigation design that reduces by 50% the use of potable water beyond the initial requirements for plant installation and establishment."

"Each building shall further reduce the generation of wastewater by one of the following methods: The installation of water-conserving fixtures (water closets, urinals) or utilizing non-potable water systems (captured rainwater, graywater, and municipally treated wastewater
(recycled water)."

For materials to be specified for construction, the following is mandated:
  • Select building materials or products for permanent installation on the project that have been harvested or manufactured in California or within 500 miles of the project site.
  • Select bio-based building materials and products made from solid wood, engineered wood, bamboo, wool, cotton, cork, straw, natural fibers, products made from crops (soy-based, corn-based) and other bio-based materials with at least 50% bio-based content.
  • Employ wood-based materials and products comprising at least 50% of a major building component, such as framing, flooring, or millwork, which are certified by one of five listed sustainably harvested certification programs.
  • Use materials made from plants harvested within a ten-year cycle for at least 2.5% of total materials value, based on estimated cost.
  • Use salvaged, refurbished, refinished, or reused materials for a minimum of 5% of the total value, based on estimated cost of materials on the project.
  • Use materials, equivalent in performance to virgin materials, with post-consumer or preconsumer recycled content value (RCV) for a minimum of 10% of the total value, based on estimated cost of materials on the project.
  • Use cement and concrete made with recycled products, fly ash, raw or calcined natural pozzolan, blast furnace slag (as a lightweight aggregate) .
  • Select materials for longevity and minimal deterioration under conditions of use.
  • Select materials that require little, if any, finishing.
  • Select materials that can be re-used or recycled at the end of their service life in the project.
  • Select materials assemblies based on life cycle assessment of their embodied energy and/or green house gas emission potentials.
"Provide readily accessible areas that serve the entire building and are identified for the depositing, storage, and collection of non-hazardous materials for recycling, including (at a minimum) paper, corrugated cardboard, glass, plastics and metals."

Environmental and health-related items establish specific limits on VOC emission of materials used within the structure, as well as regulate ventilation, CO2 emissions, tobacco smoke, lighting, outside views, and noise transmission.

Additional recommended measures include:
  • If feasible, disassemble existing buildings instead of demolishing to allow reuse or recycling of building materials.
  • Utilize a Frost-Protected Shallow Foundation.
  • Use pre-manufactured floor and roof systems to eliminate solid sawn lumber whenever possible.
The code also identifies site improvements including bicycle storage and designated parking spots for low-emissions vehicles.

I have been advocating most of these measures at www.greenhomebuilding.com for many years now, and it is heartening to see them being officially sanctioned. This is a far-reaching and well-considered attempt by California legislators to establish requisites for living sustainably. If there are going to be building codes, they might as well be green! Yeah California!