Tag Archives: wood

U.S. tall wood building prize up for grabs

Limnologen in Växjö, Sweden—taller wood-framed projects are appearing around the world. A new U.S. initiative is seeking nominees. Photo courtesy Midroc Property Development

Limnologen in Växjö, Sweden—taller wood-framed projects are appearing around the world. A new U.S. initiative is seeking nominees. Photo courtesy Midroc Property Development

The U.S. Department of Agriculture (USDA) has launched a $2 million Tall Wood Building Prize Competition, following a funding initiative announced by the Obama Administration and the U.S. forestry industry through the Softwood Lumber Board (SLB) and Binational Softwood Lumber Council (BSLC) earlier this year.

Its goal is to link rural U.S. technical expertise and products with evolving domestic and international market opportunities to showcase the application and sustainability of wood-based structural building materials. The competition seeks to identify proponents with building project(s) in the concept-, schematic-, or design-development stage that can safely and successfully demonstrate wood as a viable structural material in tall buildings. Beyond the safety, environmental, and economic benefits of wood, the initiative intends to challenge developers, designers, building officials, builders, and manufacturers to further develop and refine specification and use of structural wood products to expand opportunity for new product and market development.

Creation of taller wood buildings is becoming a trend internationally. In Ontario, the building code was recently changed to permit six-storey wood-framed buildings. (For more, see a recent Construction Canada article. Other examples exist around the world, explains Marc Brinkmeyer, SLB board chair.

“In recent years, we’ve seen a number of buildings over seven stories constructed around the world, including the 10-story Forte building in Melbourne, Australia and the 14-story Treet building in Bergen, Norway,” he said. “The opportunity to learn from what’s been done elsewhere, and build on it here is very exciting for our industry, our employees, and communities.”

Submissions meeting the competition’s criteria will be evaluated by an expert panel of design and building professionals. For more information, visit www.tallwoodbuildingcompetition.org.

Grant project follows lifecycle of urban wood

Urban lumber harvesting has emerged as an option for cities like Wisconsin.  Photos courtesy Kubala-Washatko Architects

Urban lumber harvesting has emerged as an option for cities like Milwaukee. Photo courtesy M Magazine.

By Rebecca Konya

In the October 2014 issue of The Construction Specifier, the article, “Seeing the Urban Forests for the Trees,” by J. Gerard Capell, FCSI, AIA, CCS, examined how urban lumber harvesting has emerged as an option for resources otherwise devastated by the emerald ash borer. It takes a particular look at how Milwaukee, Wisconsin, is becoming an important player in finding new opportunities for wood—carpentry, casework, and flooring included.

While sustainability is clearly important, when Milwaukee first began diverting diseased and damaged city trees from the wood chipper or the landfill for more useful purposes, it was cost savings primarily driving the effort. It turns out routing urban wood to area sawmills like Kettle Moraine Hardwoods costs about half as much as traditional disposal efforts. This was good news for both the city, which cuts down about 3600 trees annually, and urban wood itself.

“It saves us money and captures whatever value these urban logs may have,” says David Sivyer, Milwaukee’s forestry services manager.

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Whether ravaged by emerald ash borer or taken down for other reasons, urban trees can find new life in building projects as finishes, furnishes, or carpentry.

Whether ravaged by emerald ash borer or taken down for other reasons, urban trees can find new life in building projects as finishes, furnishes, or carpentry.
Photos courtesy Kubala-Washatko Architects

With Milwaukee’s urban wood utilization effort now firmly established, and plenty of ready-to-use urban wood available, there is a new effort underway to create awareness and build demand for urban wood products.

One of the movement’s most vocal advocates, Dwayne Sperber, won a 2014 Wisconsin Urban Forestry Grant from the state’s Department of Natural Resources (authorized under s. 23.097, Wis. Stat.) to study the urban wood market from removal to end-use; it culminates in an urban wood application in a commercial building project—a Colectivo coffee shop currently under construction in a Milwaukee suburb.

“This grant project is meant to bring public awareness to urban wood as a sustainable resource,” says Sperber. “There’s a real opportunity to transform fallen or condemned trees into functional products.”

Wood from reclaimed urban trees competes in a marketplace already saturated with widely recognized materials like sustainable wood from traditionally managed forests. As a result, another component of the urban forestry grant project is to develop the language necessary for architects and designers to confidently specify urban forest products in their building designs.

“Architects, designers, and contractors need to understand the particularities of sourcing urban wood,” says Sperber. “The grant is a means of educating the building industry about urban wood so it can gain greater market acceptance.”

Though the construction documentation being written as part of the grant project applies specifically to the Colectivo project, the specification will be made available to all building industry professionals via the Wisconsin Urban Wood (WUW) website. An effort by a separate but related grant project, WUW is a growing network of industry professionals committed to preserving and protecting the urban forest as a sustainable resource.

“There are specifications and guidelines for how wood is cut, how it is dried, and how it is structurally labeled,” says Capell, who is developing the urban wood specification for the Colectivo project.

Tom Kubala, a principal with the Kubala-Washatko Architects, Inc., says many architects hesitate to specify urban wood for projects because it does not have the right documents.

“The idea of establishing some kind of specification that could be followed by whoever is obtaining the wood, drying the wood, or milling it gives a little more confidence to a specifying architect,” he says.

Partnering with Kubala-Washatko to incorporate urban wood into one of their commercial building projects is another means of gaining industry validation. The firm will use donated urban ash in the interior of the Colectivo coffee shop that is part of a new town center development in the city of Mequon.

“The Mequon Colectivo is a living example of an urban wood application,” explains Sperber.

With specification language and the support of a renowned architectural firm, he is optimistic other architects and contractors will follow suit using urban wood in their own building projects. There is, after all, a certain satisfaction of using local resources rather than wasting them—especially considering the sustainability aspects of using locally sourced lumber.

Another audience the grant project is seeking to educate about urban wood is the general public, who may not immediately see the beauty in its imperfections. Unlike standard lumber that is uniform in size and look, urban wood typically has distinctive qualities like knots, gnarls, and wormwood holes.

For the use of urban wood to grow in popularity, it is necessary to change customers’ perceptions, enabling use of less-than-visually-perfect boards. It becomes important to explain how these ‘imperfections’ actually add some look and character to the finished piece.

The grant project aims to accomplish this goal through public outreach efforts like the Urban Wood Encounter at the Lynden Sculpture Garden. The exhibit, which runs from November to January 2015, is designed to introduce the public to the environmental value of urban wood within the context of a showcase of fine furniture. It challenges furniture-makers and designers to create inspiring, thoughtful, and beautiful furniture from a previously underutilized natural resource.

RKonya3Rebecca Konya is a freelance writer, and the head of Konya Communications. She can be reached at mail@konyacommunications.com.

Association Cooperation

In the October issue of The Construction Specifier, authors Ward R. Malisch, PhD, PE, and Bruce A. Suprenant, PhD, PE (both of the American Society of Concrete Contractors [ASCC]) wrote our cover story, “Bridging the Specification Gap between Divisions 03 and 09: Concrete and Floorcovering Associations Unite.” The piece looked at how their association teamed up with six other flooring groups to find a solution to a ‘specification gap’ between Divisions 03 and 09 in terms of floor surface flatness requirements.

For space reasons, we had to hold off including a little more background on how these associations collaborated. That ‘missing’ information follows, in the words of Malisch and Suprenant:

The impetus for developing the American Society of Concrete Contractors (ASCC) Position Statements came from a group of contractor members who became aware of a paper published by a national wood flooring organization—not, it should be noted, the National Wood Flooring Association (NWFA)—that stated the organization did not believe in F-numbers and felt they should not be used to measure slabs for gym floors. Rather than trying to decide how they could build a floor that meets unreasonable requirements, ASCC contractors realized they needed to spend their time and resources to educate the industry on the limitations of concrete floors. Thus was born this series, including ASCC Position Statement 6, Division 3 versus Division 9 Floor Flatness Tolerances.

Then, rather than continuing to fight their fellow contractors in the floorcovering industry, ASCC made an effort to get them on board, realizing the greater strength of a united front. ASCC first approached NWFA. With only minor rewriting, that association was eager to endorse the Position Statement.

“For the first time, instead of disagreeing, the two sides have come together to find a common solution to a problem that has cost both groups hundreds of thousands of dollars in rework,” said NWFA president/CEO Michael Martin.

Shortly thereafter, ASCC invited the National Tile Contractors Association (NTCA) to participate in a panel discussion on this topic featuring contractors and technical personnel from both disciplines. Both sides acknowledged the wisdom of a bid allowance to compensate for the incompatibility of the measuring methods, and NTCA became the second flooring association to sign on.

Bart Bettiga, NTCA executive director, commented on the reasons for the document’s usefulness.

“It is our belief this position statement is one of the most important documents we have supported in the past several years,” he said. “This statement accomplishes its goals on many levels. It educates the construction professional about important considerations that must be taken when specifying floorcovering products over concrete substrates.”

“The most important point emphasized in this position statement centers on the disparity related to meeting industry standards in the respective divisions,” Bettiga continued. “Equally important is the call for communication between the related parties and for a proactive approach to be determined prior to the commencement of the work. We strongly support the use of this statement to our members in their communication to the general contractor and architect/specifier on their projects.”

These two organizations were followed by the Flooring Contractors Association. Then, last year, Scott Conwell, director of industry development and technical services for the International Masonry Institute (IMI) contacted the ASCC, asking to add the group’s name, along with those of the Tile Contractors Association of America (TCAA) and the International Union Of Bricklayers and Allied Craftsmen (BAC) to the list of supporters.

“This ASCC Position Statement succinctly brings to light the disparity in requirements for floor flatness between the concrete and the ceramic tile trades,” says Conwell. “The paper effectively brings expectations in line, leading to increased cooperation on the job site to make any corrections to the floor that may be necessary prior to installation of the tile finish.”

Two trades with distinctively different practices and obstacles to overcome but with one goal: to deliver a high-quality product to a satisfied owner.

Seeing the Urban Forests for the Trees: Secondary benefits of our cities’ wood

Photo courtesy M MagazinePhoto courtesy M Magazine

by J. Gerard Capell, FCSI, AIA, CCS

A childhood treehouse, a place to hang a swing, or the support for a hammock in the cool shade—many of us can think back to these valuable memories that reflect the utility of trees in urban and suburban spaces. What if there were additional memories to be gained from the death and removal of those same trees? In a growing number of cities in the United States, urban forests are being recognized as a valuable, renewable resource for furnishings, paneling, flooring, or trim for residential or commercial spaces.

However, this transformation is neither straight forward nor simple. The process does not call for clear-cutting local parks—it involves the removal of trees that are diseased, storm-damaged, at the end of their natural lives, or need to be removed to make way for new development and street repairs.

Urban forestry is an industry resulting from the infestation of the emerald ash borer (EAB) that began in Michigan in 2002 and has now spread as far as Colorado, Georgia, and northeastern Canada. There are an estimated eight billion ash trees in the United States, and approximately 150 to 200 million have already died as a result of this invasive species.1 However, urban forestry is not limited to ash trees. In Milwaukee, the city cuts down and transports Norway maples, elms, honey locusts, basswood, and poplar—all of which are sent to a local mill for processing and are available for sale.

Emerald ash borers have been responsible for the felling of some 200 million trees. However, this wood could be repurposed in exciting ways. Photo © Leah Bauer, USDA Forest Service Northern Research Station

Emerald ash borers have been responsible for the felling of some 200 million trees. However, this wood
could be repurposed in exciting ways. Photo © Leah Bauer, USDA Forest Service Northern Research Station

City of Milwaukee workers loading a downed urban ash tree. Photo courtesy M Magazine

City of Milwaukee workers loading a downed urban ash tree. Photo courtesy M Magazine

 

 

 

 

 

 

 

 

Urban versus wilderness
Milwaukee is somewhat unique in that its department of forestry is responsible for cutting and trimming all city trees. The department can uniformly instruct the workers how to cut down the trees. The city also has a unique relationship with a local sawmill (Kettle Moraine Hardwoods), whose owner, Bob Wesp, has personally taught the workers how to look at a tree and keep in mind its usability as urban-cut lumber.

This might sound simple, but it is important to keep in mind the average city’s municipal employee is not a lumberjack from the Pacific Northwest with the skill and knowledge of how a mill will cut the tree into 1-by planks. For urban forestry, the first thing that needs to be done is to tell the workers the logs need to be as long as possible. Typically, tree service companies cut down trees into 915 to 1220-mm (3 to 4-ft) long logs that are small enough to fit into a Bobcat skip loader so they can be taken to the corporation yard where they will be ground into wood mulch. However, carpenters want trim that is at least 2.4 m (8 ft) long—preferably 3.1 to 3.7 m (10 to 12 ft) to eliminate mid-wall joints. Additionally, mills want a trunk or branch to be at least 254 to 305 mm (10 to 12 in.) in diameter for efficient sawing.

There are other things urban foresters must take into account. For example, by cutting too high up on the trunk or too close to the crotch of a pair of branches, one may unintentionally lose some really rich graining that will add a great deal of character to the planks. This is particularly the case for wood selected for furnishings where a unique grain pattern or coloration can make all the difference between just a piece of furniture and that special chair or table that can garner a higher price.

In regular forest-harvesting, the logs are placed on a 15 to 21-m (50 to 75-ft) tractor trailer. In urban forestry, a 25-m2 (30-cy) dumpster is the typical means of carrying the logs from the site to the mill, which means a log’s length is limited to a maximum length of about 7 m (21 ft) due to the dumpster’s length. The urban forester also needs a lift large enough to safely handle a 58 to 76-mm (20 to 30-in.) log that is 6.9 m (20 ft) long. Once the dumpster is full, it is transported to the mill.

tree crop

Emerald ash borer larvae scarring of the Cambrian layer. Photo courtesy  organicplantcarellc.com

Rough-sawn and planed urban ash board. Photos courtesy J. Gerard Capell

Rough-sawn and planed urban ash board. Photos courtesy J. Gerard Capell

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Meet the beetles
One of the first cities to undertake such efforts was Ann Arbor, Michigan, which was badly hit by the emerald ash borer. It is estimated that 7000 ash trees that lined its streets and yards were lost, and another 3000 were removed from the parks and surrounding nature areas, at a cost of at least $2 million. It is further estimated southeast Michigan lost upward of 30 million ash trees.2

EAB is believed to have come to the United States from Asia via packing crates and pallets. The beetle kills a tree by burrowing under the bark and depositing its larvae in the Cambrian layer, disrupting the tree’s ability to transport water from the roots to the leaves. Fortunately, the larvae do not damage the wood—this means if the tree is healthy and solid without rot or large splits, its lumber will be fine for higher-value uses.

The first method of EAB control was to clear-cut areas within 405 m (1320 ft) of the infested tree. Now, this radical surgery-management style is giving way to a controlled cut system such as that employed by Milwaukee in which insecticide is used to slow the EAB from destroying entire neighborhoods of trees, thereby giving the forestry department time to extend the devastation and tree replacement process out over a decade or more. The loss of so many trees within such a short time produced a significant volume of wood. Traditionally, such lumber was ground up for mulch, processed for bio-mass energy generation, or just sent to the landfill.

The Southeast Michigan Resource Conservation and Development Council (SEMIRCD) received a grant from the U.S. Department of Agriculture (USDA) to show there could be an economic benefit from the EAB problem and demonstrate markets for removed lumber.3 Through their efforts, numerous new markets for urban wood have been developed. For instance, an American Institute of Architects (AIA) Michigan award-winning project (Ann Arbor’s Traverwood Library) used reclaimed ash for flooring, wall panels, and ceilings. Structural columns utilized trees that were simply stripped and sealed leaving the scarred, rune-like patterns left by the chewing beetles.4 Similar efforts are now being employed in other cities, including Milwaukee.

Urban butternut (left) and urban red maple (right) sample panels.

Urban butternut (left) and urban red maple (right) sample panels.

Red Maple 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

From mill to shop
Once at the mill, a log may be set aside to dry, but because there might not be enough lumber to make up a pallet of one type, logs may have to wait until an adequate amount has accumulated. Unless there is a specific order for pieces of a specific size, a tree will be cut as ‘log-run,’ which is approximately 25 mm (1 in.)—or 4/4—thickness by random widths. This can be milled to 18-mm (3/4-in.) material that in turn can be used for most siding, flooring, and trim. Stair treads, mantels, and other special pieces need to be identified early so wider pieces with particularly good character can be cut at the same time. As this is log-run material, a pallet of lumber is not sorted or graded and the planks from a set of trees can range from FAS to No. 2 Common as defined by the National Hardwood Lumber Association (NHLA).

Another issue for urban lumber that is much more of a challenge is the greater likelihood that nails, wire, or bolts have been embedded in the tree. This means each log has to be magnetically scanned and cleared. Hitting even a small nail can ruin a blade, endanger workers, and result in downtime to make repairs. The mill operator in Milwaukee reported that from 30 to 35 percent of the urban trees it receives contain metal versus about two percent for trees coming from a standard forest preserve. They then have to pull those trees aside and search for the metal, and then remove it. If they cannot find the metal (or if there is too much of it), the tree may have to be discarded.

Once cut, hardwoods can take as long as 200 days to achieve 20 percent moisture content (MC) when just stacked with stickers (wood strips) between the planks. This is still a long way from the six to eight percent needed for interior use, so the wood must be put in a kiln, which takes two to four weeks to bring the wood to the desired moisture content. Then, the board can be shipped to a cabinet shop for fabrication.

If an owner or designer wants to use a particular stand of trees, the required time to turn those living trees into usable lumber for a carpenter or furniture-maker would be two to three months from the date of hewing the trees to have lumber stock ready to be milled into flooring, paneling, or trim. Most mills will have cut and dried urban lumber, but it is necessary to check to find out how much lumber is on hand so as not to delay the project.

Due to the need for a city to have a clear process to deliver its trees, most will probably have just one mill do the processing. Contractors and designers must connect with this firm, or work with another organization that has established a relationship with the mill to facilitate ordering and delivery. Groups such as Southeast Michigan Resource Conservation and Development Council in Michigan and Wudeward Urban Forest Products in southeast Wisconsin promote urban lumber use though education to the design and construction industry. More can be found on a state-by-state basis as businesses and cities look for an ecologically sound response to the losses in urban forests.

Once the lumber arrives at a cabinet shop, the real beauty of the wood emerges as the rough-sawn planks are trimmed, edged, and shaped into usable pieces. The hidden benefit of urban lumber starts to be realized at this time as richer colors and grain patterns emerge. However, since log-run lumber is not graded or sorted, splits, warping, and snapping at loose knots can easily claim upward of 50 percent of the lumber delivered from a pallet, adding to the cost to the fabricator in lost materials and time. The designer and owner may want to schedule a visit to the shop at this time to verify the design intent for the wood is being realized, especially when the piece is a feature element such as an entry wall or reception desk.

Urban ash trim at the University of Wisconsin–Milwaukee. Photographs courtesy Amy Hall

Urban ash trim at the University of Wisconsin–Milwaukee. Photographs courtesy Amy Hall

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The green forest
Another clear benefit of using urban lumber is the ability to gain credits from sustainability programs. With the U.S. Green Building Council’s (USGBC’s) Leadership in Energy and Environmental Design (LEED) program, credits can be easily claimed for Materials and Resources (MR) Credit 5, Regional Material Use.

MR Credit 7, Certified Wood, is a more problematic credit to obtain. The difficulty arises in the lack of an established recognition by the Forest Stewardship Council (FSC) of urban wood. At press time, FSC had announced there will be a motion offered at its General Assembly to be held in Seville, Spain, in the fall to ‘capture’ urban wood as part of the supply stream. Many issues will have to be resolved to establish the type of recognition, but this is a positive event that was not expected by many in the urban wood community for at least another three years.

The designer’s role through this process is that of educator and facilitator. They need to ensure the contractor (and the related subcontractors) is aware of this special product and that additional care may be required during bidding and fabrication. They also need to make certain owners are aware this unique, sustainable resource is available and can be an asset to the completed project. As mentioned, the designer needs to be much more hands-on to facilitate the proper use of the urban lumber. It is akin to working with a fine marble slab—the goal is to capture as much of the intrinsic drama and beauty possible from a natural and non-uniform material.

Specifications
Specifiers have a key role in ensuring urban lumber is correctly specified and incorporated in the project. Typical sections that would be used are MasterFormat 06 20 00–Finish Carpentry, 06 41 00–Architectural Casework, and 09 64 00–Wood Flooring. A small but important addition to a standard master specification should be a brief definition such as:

Urban Lumber: Wood that is obtained from trees located in cities, towns or suburbs not harvested for their timber value, but removed because of insect, disease or circumstance.

This will help clarify the material, distinguishing it from salvaged lumber, which may be collected from an existing building, or from rivers and lakes.

This an example of urban ash stair treads.

This an example of urban ash stair treads.

Other key areas should be inserted into a specification section depending on the level of desired aesthetic control. They include:

  • samples of adequate size and length to show the range of acceptable color, grain, and acceptable flaws;
  • pre-fabrication meeting, where the designer, owner, contractor, and millworker meet to establish the quality of the finish work;
  • mockup approval of casework, paneling, or flooring to verify the desired quality level;
  • list of approved mills or suppliers that deal with urban wood near the project; and
  • clarification of the grade (or lack thereof) provided by the mill or supplier for the urban wood—NHLA grades are probably the best source for these, but there is no recognized grade for log-run material (it should be listed to give the cabinet shop an idea of what to expect).

Another important provision, especially for casework or stairs, is to use (AWI/AWMAC/WI) standards to define the expected quality standard of the completed work. These standards control the amount of grain and color-matching between members to ensure a uniform appearance is achieved (or not achieved, depending on the designer’s intent). This is especially the case when using wood such as ash that can have a broad variety of color and grain pattern within the same board.

When the designer is aware of the possibilities, a truly remarkable piece of casework or paneling can be achieved. By utilizing urban lumber, owners can attach a great story and add a unique component to any building.

Conclusion
From the disaster of emerald ash borer infestation emerges new opportunities to enrich urban spaces and provide new memories from city trees. Architects, contractors, and owners have the ability to use and promote this unique resource, but as with any ‘new product,’ the various parameters must be understood for its correct use to achieve the best results for all involved.

Provided design/construction professionals and urban forestry workers know the ideal criteria for board length, importance of identifying special cuts early, and the need to sort or grade material prior to delivery to fabricators to minimize waste results, urban lumber has great opportunity for richer character in the wood, making for a unique finish with a great back story.

Notes
1 This comes from Therese Poland and Deborah Therese’s April/May 2006 article in Journal of Forestry, “Emerald Ash Borer: Invasion of the Urban Forest and the Threat to North America’s Ash Resource.” (back to top)
2 See Marianne Rzepka’s August 22, 2010 article in the Ann Arbor Chronicle, “Seeds and Stems.” (back to top)
3 For more information, visit www.semircd.org. (back to top)
4 The project was profiled in Bradford McKee’s October 6, 2009 article, “Traverwood Branch Library,” which appeared in Architect. (back to top)

J. Gerard Capell, FCSI, AIA, CCS, is principal of Capell Design Associates in Milwaukee, Wisconsin, providing architectural design and specification writing services. His experience has broadly evolved from his work in California, Wisconsin, and Florence, Italy; this includes work as a rough and finish carpenter, architect, and specification writer on healthcare, education, civic, residential, senior living, retail, and industrial projects. Capell has served on CSI’s Certification Committee and Board, along with positions at the region and chapter level over his 28 years as a member. He can be reached at jgcapell@wi.rr.com.

Energy Efficiency and Building with Wood: Six Building Lifecycle Steps

Buildings have an impact on people and the environment throughout their entire lifecycle, starting with extracting resources from the earth to putting them back in the earth, or burning them, at the end of their lives. To evaluate the effect of buildings in this regard, everything from the energy they consume, the waste they generate, and the carbon dioxide (CO₂) they emit must be considered throughout the six major cycles below.

The combination of wood and the Passive House standard is a common-sense approach that can have a very positive lifecycle impact on the environment. In fact, according to a report from the U.S. Forest Service, wood in building products yields fewer greenhouse gases (GHG) than other common materials.*

1. Resource extraction
Everything in buildings comes from natural resources, some of which grow relatively quickly above the ground (e.g. wood), while others take millions of years to form below the ground (e.g. materials derived from fossil fuels). Taking a look at wood, the amount of heat, water, and pollution generated compared to extracting iron to produce steel, or extracting limestone to produce cement is significantly lower.**

The lifecycle of wood has a smaller impact. For example, the sun hits the tree, and the tree grows. It can be cut down with light machinery and a new tree is planted. It absorbs carbon, provides oxygen, and can be used in the future. In this context, it means a more sustainable production, compared to making concrete or steel, where digging for oil, coal, or natural gas and then burning it is a prerequisite to extracting the raw materials from the earth.

2. Manufacturing
The real ‘weight’ of a material—including resources, water, and energy used at the entry point of a manufacturing facility—compared to the material that comes out at the other end is referred to as the ‘ecological backpack.’ This measures the environmental impact of manufacturing products. Common sense suggests it requires less resources and energy to manufacture wood products compared to concrete and steel. Heavy timber and mass timber products can meet the same structural and fire requirements that also govern concrete and steel.

3. Off-site and onsite production
In many cases, the process of constructing buildings is antiquated, relying on manual and labor-intensive onsite processes. Other fields, such as manufacturing automobiles, have advanced considerably using automation and an industrialized system approach to designing and building, where the energy efficiency, in miles per gallon, can be guaranteed and the assembly occurs in a modern factory. Modern wood prefabrication processes can offer new opportunities and better working conditions. In this respect, building with wood can offer fast and efficient options for construction.

4. Operation
The natural resources needed to produce and deliver the energy consumed to heat and cool buildings for lighting, appliances, and water is the highest of all six lifecycle steps. While more efficient lighting and appliances can be specified, the only way to reduce long-term heating and cooling loads is to improve the building envelope. Airtightness is the most important element that has made the Passive House standard succeed. It can easily be achieved using modern wood carpentry, as discussed in this article.

5. Demolition
At the end of a building’s lifecycle, products are usually disposed of in landfills. Using a system approach to construction, buildings can be designed so they can be disassembled and separated for recycling. Design optimization, use of recovered wood, and specifying jobsite waste to be separated and taken to a local recovery center are all ways to reduce, reuse, and recycle.

6. Recycling
Wood from buildings can be recovered for use in other buildings or be employed to create furniture or other products. Even at the end of their second or third ‘life,’ wood products can be burned to generate energy or decompose naturally in the earth.

*See USDA Forest Service’s “Science Supporting the Economic and Environmental Benefits of Using Wood and Wood products in Green Building Construction.”
** For more, see the International Journal of Life Cycle Assessment article, “Wooden Building Products in Comparative LCA: A Literature Review,” by Frank Werner and Klaus Richter. Visit www.vhn.org/pdf/LCA-Wood-algemeen.pdf.

To read the full article, click here.