Rammed earth has been a part of the alternative materials scene in Northern California since the mid 1970’s, when we first broke through the building permit barrier. Initially our goal was to develop a resource-efficient construction system that would be affordable and widely adopted by the building industry. We began with a strong commitment to construction simplicity and to the use of site materials.
As market confidence and client appreciation increased, we continued to improve the technology to meet the demands for a crisp, complex and highly refined product. Rammed earth’s reputation as an organic, rustic, inexpensive solution for the owner builder morphed into the perfect expression of artistic whimsy for those who could afford any structural system but preferred the visual power of a thick monolithic wall. Thirty years ago “rammed earth” was unknown in California building terminology. Today it’s on the drafting boards of some of the world’s leading architects.
Now that rammed earth has grown into the ultimate demonstration of client commitment to green building, we need to step back and consider what might have been lost along its road to recognition. Maintaining the connection to resource efficiency remains our primary goal, but as projects involve more complex wall systems with tighter specifications, formulations become more dependent on the uniform soil gradations of imported quarry products and stabilization ratios rise in response to engineering demands.
The upside is that today’s rammed earth walls are immaculate, as well as being safe, quiet and comfortable. The downside is too many eighteen-wheelers on the road burning diesel and too much imported cement from China. Our carbon footprint increases in proportion to the demand for art walls rather than simple structure. The fact is, a hand made wall with its human imperfections is much “greener” than the perfectly plumb, sharp edged, stratified art walls that are currently in demand.
The challenge now is to re-focus on our original vision: can we return to site materials, reduce cement content, simplify formwork and still produce a beautiful, affordable, and supremely sustainable wall system? It is imperative that we try – for the sake of future builders.
David Easton is a graduate of Stanford Engineering’s Product Design Department in 1970; founder of Rammed Earth Works, California’s oldest structural earth wall company; author of The Rammed Earth House; and developer of mechanical systems, soil mix designs, quality control procedures, and seismic strategies specific to building with site resources in earthquake regions. His project portfolio ranges from low-cost solutions for construction in developing countries to high-end commercial and residential projects in the United States.
Project Description for the Ningbo Eco-Corridor
Location: Ningbo, China
Scope of the Project
The landscape architects, SWA Group, provided master planning and conceptual design services for the 250-acre metropolitan Eco-Corridor Park located in Ningbo’s East Town, an area of 6 square miles that currently includes a mixture of industrial and agricultural land uses. The plan revitalizes and regenerates the existing environments to create a “Green Lung” for the city, providing recreation, education, and cultural facilities for the entire city. The design provides habitat for flora and fauna and creates a constructed open space system for recreation and adaptive reuse.
To achieve these goals, the design team proposed four strategies of integration, balance, creation, and sustainability, as described below. Master planning and conceptual design phases are complete and the first phase of schematic design and site analysis is now underway.
Located in the heart of the Yangtze River Delta on China’s Coastline, Ningbo is one of China’s oldest cities. With an area of 3,616 square miles and a population of 5.43 million, Ningbo has been a well-known key port for foreign trade since ancient times. Bordered by Shanghai to the north and Hangzhou to the east, Ningbo is an important industiral city, foreign trade port, and economic center for east China. Water is integral to the shape and function of the city: “Ningbo,” meaning “Tranquil Waters,” overlooks the Handzhou Bay and rests within the matrix of industrial water canals and delta river fabric of land.
In 2002, to support the growth of the Old City and upgrade infrastructure, the governement called for a master plan for “Eastern New City” to add 6 square miles (3,953 acres) to the urban area. The development of the “Eastern New City” triggered a strategy to build Ningbo as a larger metropolitan area of economic and environmental importance and set the stage for an ecological approach to development.
The Ecological Corridor
The Master Plan for the Eastern New City developed along a grid framework with an east-west “central” corridor and north-south “ecological” and “river” corridors. The north-south Eco-Corridor forms a greenbelt linking the city’s business, governmental, cultural and entertainment districts.
Ningbo’s Eco-Corridor balances the impact of new development and revitalizes and regenerates the natural environment to:
- create a “Green Lung” for the city
- offer a link between humans and their environment
- create opportunities for education
- revitalize and improve existing ecosystems
- restore and create new species habitats
- create a network of open spaces for recreation and adaptive reuse
- provide cultural facilities to connect different land uses in a common space
- filter and treat canal and storm-water to release cleaner (level II) water to the river
Framework for Analysis and Planning
The four key elements influencing the design were: integration of the environment within the existing urban fabric; balance between environmental processes and human habitation; creation of positive open spaces, spatial character, and park identity; and sustainability emphasized throughout the design.
Hui-Li Lee is a Principal at SWA Group, a world reknown landscape architecture, planning, and urban design firm.
There are a number of exciting design trends that are quickly becoming mainstream in architecture and development around California. Mostly due to the continuing drought and concerns over water availability, these trends are simply implemented and have an enormous impact on a broad scale. One of the latest trends to receive publicity is the re-emergence of rainwater harvesting systems. Though the idea of capturing and storing rainwater is ancient, the concept of harvesting rainwater from downspouts has been designed and implemented in many projects for several decades.
At this point homeowners and commercial property owners are taking the steps to have rainwater harvesting systems designed and installed at their residences and project sites ranging in sizes from 1,000 to 30,000 gallons and more. These systems, which for the most part are used for irrigation, simply divert the roof water through simple filters into storage tanks and then direct it to landscapes when needed. When designed properly, these systems can provide adequate water for landscaping irrigation and other outdoor needs, as well as a myriad of valuable on-site and off-site benefits. Benefits include increased soil health, reduced stormwater runoff, conservation of potable water and associated energy for pumping and treatment. These benefits are more difficult to quantify but nonetheless provide a much needed advantage especially in the realm of strategic planning.
When designing rainwater harvesting systems, it is important to calibrate and size the capacity for the application it supplies. In other words, a determination of how much water is being used needs to be made to give an idea of how much water needs to be captured. This water balancing calculation is often difficult to evaluate and typically requires the skills of an experienced professional involved in the latest irrigation, planting, and water conservation design techniques. During the early planning stages, the design of a landscape can be crafted to minimize water use while providing the desired aesthetics, along with the installation of a rainwater harvesting system to handle the irrigation needs. However, existing landscapes can also be modified to utilize much less water and integrate a rainwater harvesting system to provide a large quantity of irrigation demand.
Rainwater harvesting systems, which are commonplace in Australia and other drought plagued countries, have also spurred an increased awareness of the importance of water conservation. Studies conducted show that just the presence of a rainwater harvesting system can stimulate a water savings of 60 percent. At a time when the whole nation is striving to do more with less, it is wise and satisfying to go back to the basics, regard our natural resources with the utmost importance, and do our part to contribute to the quality of our rivers and bays, landscapes, and security for generations to come.
Bobby Markowitz, founder of Earthcraft Landscape Design, has been designing rainwater harvesting systems and educating professionals for nearly a decade. A licensed Landscape Architect, Accredited Professional by the American Rainwater Catchment System Association, Certified Permaculturist (taught by Founder Bill Mollison), Mr. Markowitz has advanced the viability of water conservation systems into the forefront of landscape architecture. A graduate of Rutgers University, Mr. Markowitz’s work is influenced by his study abroad in Japan and advanced water harvesting workshops in Australia. A frequent guest lecturer and keynote speaker for numerous Landscape Architecture and Rainwater Catchment System Associations, Mr. Markowitz has provided valuable insight into the design of sustainable sites and water conservation systems. In addition to his practice, Bobby Markowitz also teaches “Rainwater Harvesting System: Principles and Design” at Cabrillo College.
My first exposure to waste diversion on a jobsite was a response to LEED requirements. Of all the standards we had to meet, practices we had to modify, and requirements we had to satisfy waste diversion presented the most tangible upside – across the board. It’s obvious, too. Once you have modified your waste handling practices, you realize a few things: first, it is just like recycling at your own house, so it’s something we’re all use to by now; and second, by the time the first loads of cardboard, plastics, and clean lumber cut-offs have been hauled away you can see the enormous quantities of material that you have diverted from the landfill.
The process is really simple. You can create a segregated waste area with separate space for wood, cardboard, plastics, and garbage that fits the space you have on the jobsite whether small or large. If the jobsite is spacious and you can fit a few containers, your local waste handler can often provide separate bins. Otherwise, simple plywood boxes work fine. Most local dumps have recycling centers, which makes dropping the material off very easy. There is generally a significant cost savings when leaving clean material at the dump rather than “construction debris.” On the LEED project referenced above, we saw a 40% reduction in our typical waste handling costs.
Carpenters and tradespeople are generally resourceful, so we’ve found this effort integrated into the jobsite operations smoothly. With our own crews we found that with our new practices of segregating and diverting clean material from the dump, there have been trickle-down benefits. For example, instead of cutting up new lumber for structural blocking, our crew is salvaging from the clean waste lumber pile first.
As a builder, one of the most astonishing things we see is how much material goes into even the most sustainable homes. And often there is a lot of waste produced in an effort to build such homes. By segregating the waste material we calculated that 85% or more of the material could be diverted from the landfill. It’s clear that changing this one practice can make the process of constructing a green home much more sustainable.
Brendan Connolly manages projects and is COO for Groza Construction in Monterey, CA.
With the official launch of LEED for Homes in February of 2008, we were already consulting on several custom LEED-H pilot projects. We provide LEED-H “Representative” services through the LEED-H “Provider” in California, Davis Energy Group. The Representative is similar to having a LEED consultant on a LEED-NC project, except there is a strict limitation on the Representative’s time, since they are contracted through the Provider in an effort to keep certification costs down. The Provider is contracted by USGBC to act as the local agent for USGBC, since there is such a large volume of residential projects compared with other LEED programs. The program works fairly well, as long as the architect and contractor are savvy with green building, energy, water and indoor air quality.
Our most successful projects hired us independently to provide additional LEED-H consulting, which eased the burden on the design team and contractor. Some owners and architects initially expect LEED-H fees paid to USGBC to cover the consulting portion, which Davis Energy describes as the “how you do it” scope of work. Fees charged by USGBC, including the Representatives’ time, actually only cover the “did you do it?” scope of work. Davis Energy encourages owners and design teams to hire the Representatives independently, if the design team needs support in meeting prerequisites and credits. The most successful projects either pay someone in-house or hire a LEED consultant to coordinate, update, and administrate the LEED-H process. LEED-H requires numerous documents in addition to the LEED-H checklist, such as the Thermal Bypass Checklist, Accountability Forms, Durability Evaluation, and Rater Checklist. Keeping track of all these documents and preparing them at the appropriate time is challenging and confusing, particularly given the ongoing evolution of the LEED-H program. It is also important to keep in mind that the design team, owner, and contractor are also required to produce supporting documentation for each credit. Many people have the false impression that a LEED consultant prepares everyone’s documentation for them.
The main areas of discussion around LEED for Homes are hard and soft costs, prerequisites and credits. I’ve heard people say that only the top 15% of homes are targeted for LEED-H. This may be due to design team experience, quality of construction, potential added costs, and sheer will of the owner and architect. We had 5 LEED-H Platinum Homes certified last year where the added hard costs were very low; in the range of 2%-5% with a per square foot cost under $250. Those five homes are also net-zero energy homes. We also have the other spectrum of larger “green” custom homes that do not fit into Sarah Susanka’s “Not So Big House” concept; I’ll call them “Case Study Green Homes.” Added costs for LEED on these case study projects may actually be a smaller fraction of the overall costs, since volume and fancy finishes typically outweigh green elements and systems. Our hope is that working together, we can streamline the LEED-H program with the goal of added hard costs under 2% and added soft costs for the entire team under $10,000. It would be interesting to hear what others have to say about added soft costs and program efficiency improvements.
LEED-H Silver house in Palm Springs by Solterra Development
Michael Heacock + Associates is a LEED consulting firm with offices in San Francisco and Santa Barbara. Their work includes schools, commercial, public, institutional and residential projects.
California Academy of Sciences photo: Tom Fox
As a part of the Landscape Architecture firm for the new California Academy of Sciences Building in San Francisco, SWA Group, I wanted to share one of lesser known successes of the 2.5 acre Vegetated/Living Roof. This success is the creation of a native landscape habitat within the Golden Gate Park, located three stories above the ground plane. The Academy’s roof is planted with native plants which separates the native plantings from the non-native plantings of the park below. Since the installation of native species, the roof has begun to naturalize with native insects, bird habitats, and non-planted plants that have migrated to their preferred location on the roof. Researchers have been finding that there are more native insect species on the roof than in the surrounding park below, and that this may be attributed to the use of native plant material on the roof, according to researchers. The roof has created a native refuge that will allow the seven hill topped roof to continue grow and evolve into a native California hillside.
Along with the creation of the native habitat, the roof structure is also collecting water that falls on the roof, including the water irrigation runoff in addition to precipitation. The roof’s water run off is directed to a recharge chamber located under the building that then recharges the aquifers within Golden Gate Park. These aquifers also supply the park with its own irrigation water, which irrigates the entire park including the Academy Building. So rainfall and supplemental irrigation that the roof’s plants cannot use, and would otherwise go into a storm drain, now go into the recharging of the natural aquifers and can be used again to keep the roof alive. The roof acts as a successful and symbiotic living part of its environment that functions as a part of its own healthy habitat by providing animal and plant habitats while also aiding in the site’s hydrological process of aquifer recharge. The roof of this great building is proving truly to be a Living System.
SWA Group Project Team: John Loomis, Laurence Reed, and Zachary Davis
Photography by Tom Fox
Bird's-eye view photo: Tom Fox
Viewing platform on living roof photo: Tom Fox
Living roof detail photo: Tom Fox
On top of living roof, looking at DeYoung Museum photo: Tom Fox
Travis Theobald is an Associate at SWA Group, a world renown landscape architecture, planning, and urban design firm.
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