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Why Wood (FAQ)

Discover why wood is the sustainable and versatile choice for your projects.

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Wood is biodegradable – that’s a characteristic we normally consider to be one of the benefits of choosing natural materials. Organisms exist that can break down wood into its basic chemicals so that fallen logs in the forest can contribute to the growth of the next generation of life. This process – essential in the forest – must be prevented when we use wood in buildings.

A variety of fungi, insects, and marine borers have the capability to break down the complex polymers which make up the wood structure. In Canada, fungi are a more serious problem than insects. The wood-inhabiting fungi can be separated into moulds, stainers, soft-rot fungi and wood-rotting basidiomycetes. The moulds and stainers can discolour the wood however they do not significantly damage the wood structurally. Soft-rot fungi and wood-rotting basidiomycetes can cause strength loss in wood, with the basidiomycetes the ones responsible for decay problems in buildings. With regard to insects, carpenter ants only cause problems in decayed wood, and significant subterranean termite activity is confined to a few southern areas of Canada. However, other parts of the world have a serious problem with termites.

A decaying log Decayed wood is the result of a series of events including a sequence of fungal colonization. The spores of these fungi are ubiquitous in the air for much of the year. Wood-rotting fungi require wood as their food source, an equable temperature, oxygen and water. Water is normally the only one of these factors that we can easily manage. This may be made more difficult by some fungi, which can transport water to otherwise dry wood. It can also be difficult to control moisture once decay has started, since the fungi produce water as a result of the decay process.

The outer portion of this log is being attacked by a decay fungus. Note that the damage is held back at the line between heartwood and sapwood. To understand why, click here to read about natural durability.

 

More Information

Click Here for a 26-page paper on biodeterioration, including illustrations and bibliography.

For answers to common questions on decay, visit the FAQ page

Termites, sometimes called “white ants” are a social insect, more closely related to cockroaches than ants. They can be distinguished from ants by the absence of a narrow waist on the body and their typically white colour. Under a hand lens, termite antennae are straight whereas those of ants have an elbow. Flying reproductive termites (alates) can be distinguished from flying ants by the equal size of all four termite wings. Three types of termites can be distinguished on the basis of their moisture requirements:

  • Damp-wood termites
  • Dry-wood termites
  • Subterranean termites

Termites

Damp-wood termites are particularly prevalent in coastal British Columbia and the Pacific Northwest of the USA. They only attack and help physically break down decaying trees in forest ecosystems and can be controlled by eliminating the moisture source which has led to decay. They are rarely a problem in buildings.

Termites2

Dry-wood termites on the other hand pose significant hazards to exposed, accessible wooden infrastructure, since they need no significant moisture source, and mated pairs can fly into buildings and start up a nest in dry wood. Consequently, control measures designed to separate wood from soil or moisture are ineffective. On the North American Continent, dry-wood termites are found only from the extreme south of the USA into Mexico.

Subterranean termites do need a reliable source of moisture, normally the soil, but they have the capability to carry their required moisture needs into dry wood in buildings. Although satellite nests can occur in buildings, their main nests are normally in soil or wood in contact with soil. Subterranean termites build characteristic shelter-tubes (tunnels) of mud, wood fragments and bodily secretions, which allow them to pass from the soil to wood above ground without being exposed to drying air or predators. These shelter tubes can extend for several metres over inert substrates, such as concrete foundation walls. Termites can also pass through cracks in concrete as narrow as 1.5 mm. Within the subterranean group, one particular species: the Formosan termite (Coptotermes formosanus Shiraki), is the most problematic for wooden infrastructure. Although individuals are smaller than the species mentioned above, because of sheer numbers Formosan termite colonies can be nine times more aggressive in terms of wood consumption. This species is particularly problematic in parts of Southeastern USA, particularly Florida, where it was introduced after WWII. It is unlikely to spread north into Canada although Canada does have other, less-aggressive species of subterranean termites. Subterranean termites are the most economically important group worldwide.

More Information

Click here for a termite map of Canada.

Click here for a termite map of SW Ontario.

Click here for a termite map of British Columbia. 

 

Additional Sources of Information on Termites

Louisiana State University Agricultural Center

City of Guelph

Municipality of Kincardine

 

Please refer to the pdf documents below for Frequently Asked Questions pertaining to durability:

General

Wood Decay and repair

Discoloration

Finishing

Mould

Treated Wood

Fortunately for Canada, most of this country lies north of the limit for termites on the North American continent. However, because termites and people both prefer the warmer parts of this country, 20% of Canada’s population live in areas where termites are present. Long winters limit termite activity in the wild, but the warmth provided by our buildings seems to encourage more serious problems in urban environments. Damage caused by the Eastern subterranean termite, (Reticulitermes flavipes Kollar), has reached economically important levels in areas of Toronto and other cities in Southern Ontario. There are some suggestions that the Western subterranean termite, (Reticulitermes hesperus Banks), may be causing significant damage in the Okanagan region of British Columbia.

Termites are a much more serious threat in many of our export markets such as the Southeastern USA, Japan and Southeast Asia. While termite control measures appropriate to each region are specified in local and regional building codes, an overview of such measures may be of use to Canadian marketers of wood products and manufactured homes. Termite control measures can be broadly grouped into six categories:

  1. Suppression
  2. Site Management
  3. Soil Barrier
  4. Slab/foundation details
  5. Structural durability
  6. Surveillance and Remediation

Click Here for more details on the 6 strategies

More Information

 

Termite Control and Wood-Frame Buildings– 11-page illustrated bulletin from CWC, further covering the 6-point integrated strategy discussed. Includes photos of termite control products.

Integrated Control of Subterranean Termites: The 6S Approach. This 20-page Forintek paper introduces and thoroughly discusses the 6-point integrated strategy. Includes very specific design and maintenance advice.
Termite Map of North America

 

Combatting Termites – very short and simple summary fact sheet from Forintek.

Holes drilled to apply depot, supplementary or remedial treatments should be on vertical surfaces or undersides, where possible, to avoid creating additional routes for moisture entry. In the case of supplementary treatment, cut ends should be placed so they are not in ground contact where possible.

Holes for treatment should not be drilled below ground level if it can possibly be avoided. All holes should be closed with a tight-fitting plug. Ideally this should be removable to allow re-treatment. Holes for water-soluble treatments should be placed in the right locations to intercept moisture close to its points of entry. Look carefully at the structure and think about moisture sources, water traps, moisture entry points, moisture flow and signs of moisture entry.

Moisture sources include direct rainfall, diverted rainfall (via windows, cladding, balcony and walkway surfaces, roof overhangs, flashing, parapets, eavestroughs and downspouts), rain penetration of moisture barriers via nail holes, splits, failure of joints or deterioration of caulking, rain splash, blowing snow, ice dams, condensation, concrete foundations, soil contact, irrigation systems, drain and plumbing leaks.

Water traps include metal “shoes”, V joints, checks, appressed boards, cupped horizontal surfaces and anywhere a rim is created at the edge of a horizontal surface. Accumulation of dirt and debris often indicates a water trap. Growth of algae also indicates locations where moisture hangs around longer after rain.

Moisture entry points include all locations with end grain, around nails, screws and bolts plus any other holes or penetrations, checks and delaminations.

Moisture flow in wood may be 100 to 1000 times faster along than across the grain. Patterns of moisture distribution in wood are therefore commonly elongated cones or lens shapes centred on the point of entry.

Signs of moisture entry include swelling, darker colouration, fungal stain, iron stain around fasteners, nail popping and flaking of film-forming surface finishes. Confirmation of moisture contents conducive to decay can be made using electrical-resistance type moisture meters. Capacitance-type moisture meters may also be useful, but these can give erroneous results in the area of metal fittings.

Click Here for more information of field treatment

Of all the energy used in North America, it is estimated that 30 to 40 percent is consumed by buildings. In Canada, the majority of operational energy in residential buildings is provided by natural gas, fuel oil, or electricity, and is consumed for space heating. Given the fact that buildings are a significant source of energy consumption and greenhouse gas emissions in Canada, energy efficiency in the buildings sector is essential to address climate change mitigation targets.

As outlined in the Pan-Canadian Framework on Clean Growth and Climate Change, the federal, provincial and territorial governments are committed to investment in initiatives to support energy efficient homes and buildings as well as energy benchmarking and labelling programs.

Despite the expanding number of choices for consumers, the most cost-effective way to increase building energy performance has remained unchanged over the decades:

• maximize the thermal performance of the building envelope by adding more insulation and reducing thermal bridging; and

• increase the airtightness of the building envelope.

The building envelope is commonly defined as the collection of components that separate conditioned space from unconditioned space (exterior air or ground). The thermal performance and airtightness of the building envelope (also known as the building enclosure) effects the whole-building energy efficiency and significantly affects the amount of heat losses and gains. Building and energy codes and standards within Canada have undergone or are currently undergoing revisions, and the minimum thermal performance requirements for wood-frame building enclosure assemblies are now more stringent. The most energy efficient buildings are made with materials that resist heat flow and are constructed with accuracy to make the best use of insulation and air barriers.

To maximize energy efficiency, exterior wall and roof assemblies must be designed using framing materials that resist heat flow, and must include continuous air barriers, insulation materials, and weather barriers to prevent air leakage through the building envelope.

The resistance to heat flow of building envelope assemblies depends on the characteristics of the materials used. Insulated assemblies are not usually homogeneous throughout the building envelope. In light-frame walls or roofs, the framing members occur at regular intervals, and, at these locations, there is a different rate of heat transfer than in the spaces between the framing members. The framing members reduce the thermal resistance of the overall wall or ceiling assembly. The rate of heat transfer at the location of framing elements depends on the thermal or insulating properties of the structural framing material. The higher rate of heat transfer at the location of framing members is called thermal bridging. The framing members of a wall or roof can account for 20 percent or more of the surface area of an exterior wall or roof and since the thermal performance of the overall assembly depends on the combined effect of the framing and insulation, the thermal properties of the framing materials can have a significant effect on the overall (effective) thermal resistance of the assembly.

Wood is a natural thermal insulator due to the millions of tiny air pockets within its cellular structure. Since thermal conductivity increases with relative density, wood is a better insulator than dense construction materials. With respect to thermal performance, wood-frame building enclosures are inherently more efficient than other common construction materials, largely because of reduced thermal bridging through the wood structural elements, including the wood studs, columns, beams, and floors. Wood loses less heat through conduction than other building materials and wood-frame construction techniques support a wide range of insulation options, including stud cavity insulation and exterior rigid insulation.

Research and monitoring of buildings is increasingly demonstrating the importance of reducing thermal bridging in new construction and reducing thermal bridges in existing buildings. The impact of thermal bridges can be a significant contributor to whole building energy use, the risk of condensation on cold surfaces, and occupant comfort.

Focusing on the building envelope and ventilation at the time of construction makes sense, as it is difficult to make changes to these systems in the future. High performance buildings typically cost more to build than conventional construction, but the higher purchase price is offset, at least in part, by lower energy consumption costs over the life cycle. What’s more, high performance buildings are often of higher quality and more comfortable to live and work in. Making buildings more energy efficient has also been shown to be one of the lowest cost opportunities to contribute to energy reduction and climate change mitigation goals.

Several certification and labeling programs are available to builders and consumers address reductions in energy consumption within buildings.

Natural Resources Canada (NRCan) administers the R-2000 program, which aims to reduce home energy requirements by 50 percent compared to a code-built home. Another program administered by NRCan, ENERGY STAR®, aims to be 20 to 25 percent more energy efficient than code. The EnerGuide Rating System estimates the energy performance of a house and can be used for both existing homes and in the planning phase for new construction.

Other certification programs and labelling systems have fixed performance targets. Passive House is a rigorous standard for energy efficiency in buildings to reduce the energy use and enhance overall performance. The space heating load must be less than 15 kWh/m2 and the airtightness must be less than 0.6 air changes per hour at 50 Pa, resulting in ultra-low energy buildings that require up to 90 percent less heating and cooling energy than conventional buildings.

The NetZero Energy Building Certification, a program operated by the International Living Future Institute, is a performance-based program and requires that the building have net-zero energy consumption for twelve consecutive months.

Green Globes and Leadership in Energy and Environmental Design (LEED) are additional building rating systems that are prevalent in the building design and construction marketplace.

 

For further information, refer to the following resources:

Thermal Performance of Light-Frame Assemblies – IBS No.5 (Canadian Wood Council)

National Energy Code of Canada for Buildings

Natural Resources Canada

BC Housing

Passive House Canada

Green Globes

Canadian Green Building Council

North American Insulation Manufacturers Association (NAIMA)

International Living Future Institute

Concerns about climate change are encouraging decarbonization of the building sector, including the use of construction materials responsible for fewer greenhouse gas (GHG) emissions and improvements in operational performance over the life cycle of buildings. Accounting for over 10 percent of total GHG emissions in Canada, the building sector plays an important role in climate change mitigation and adaptation. Decreasing the climate change impacts of buildings offers high environmental returns for relatively low economic investment.

The Government of Canada, as a signatory to the Paris Agreement, has committed to reducing Canada’s GHG emissions by 30 percent below 2005 levels by 2030. In addition, the Pan-Canadian Framework on Clean Growth and Climate Change acknowledges that forest and wood products have the ability to contribute to the national emissions reductions strategy through:

  • enhancing carbon storage in forests;
  • increasing the use of wood for construction;
  • generating fuel from bioenergy and bioproducts; and
  • advancing innovation in bio-based product development and forest management practices.

The importance of the forestry and wood products sector as a critical component toward mitigating the effects of climate change is also echoed by the Intergovernmental Panel on Climate Change (IPCC); stating that a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks while producing timber, fibre, or energy, generates the largest sustained benefit to mitigate climate change. In addition, the IPCC proclaims that “mitigating options by the forest sector include extending carbon retention in HWP [harvested wood products], product substitution, and producing biomass for bioenergy.”

The Canadian forest industry is pledging to remove 30 megatons of carbon dioxide (CO2) a year by 2030, equivalent to 13 percent of Canada’s national commitments under the Paris Agreement. Several mechanisms will be employed to meet this challenge, including:

  • product displacement, using bio-based products in place of fossil fuel-derived products and energy sources;
  • forest management practices, including increased utilization, improved residue use and land use planning, and better growth and yields;
  • accounting for long-lived bio-based product carbon pools; and
  • higher efficiencies in wood product manufacturing processes

Canada is home to 9 percent of the world’s forests, which have the ability to act as enormous carbon sinks by absorbing and storing carbon. Annually, Canada harvests less than one-half of one percent of its forest land, allowing for the forest cover in Canada to remain constant for last century. Sustainable forest management and legal requirements for reforestation continue to maintain this vast carbon reservoir. A forest is a natural system that is considered carbon neutral as long as it is managed sustainably, which means it must be reforested after harvest and not converted to other land uses. Canada has some of the strictest forest management regulations in the world, requiring successful regeneration after public forests are harvested. When managed with stewardship, forests are a renewable resource that will be available for future generations.

Canada is also a world leader in voluntary third-party forest certification, adding further assurance of sustainable forest management. Sustainable forest management programs and certification schemes strive to preserve the quantity and quality of forests for future generations, respect the biological diversity of the forests and the ecology of the species living within it, and respect the communities affected by the forests. Canadian companies have achieved third-party certification on over 150 million hectares (370 million acres) of forests, the largest area of certified forests in the world.

The forest represents one carbon pool, storing biogenic carbon in soils and trees. The carbon remains stored until the trees die and decay or burn. When a tree is cut, 40 to 60 percent of the biogenic carbon remains in the forest; the rest is removed as logs and much of it is transferred to the wood products carbon pool within the built environment. Wood products continue to store this biogenic carbon, often for decades in the case of wood buildings, delaying or preventing the release of CO2 emissions.

Wood products and building systems have ability to store large amounts of carbon; 1 m3 of S-P-F lumber stores approximately 1 tonne of CO2 equivalent. The amount of carbon stored within a wood product is directly proportional the density of the wood. The average single-family home in Canada stores almost 30 tonnes of CO2 equivalent within the wood products used for its construction. Most bio-based construction products actually store more carbon in the wood fibre than is released during the harvesting, manufacturing and transportation stages of their life cycle.

In general, bio-based products like wood that are naturally grown with help from the sun have lower embodied emissions. The embodied emissions arise through the production processes of building materials, starting with resource extraction or harvesting through manufacturing, transportation, construction, and end-of-life. Bioenergy produced from bio-based residuals, such as tree bark and sawdust, is primarily used to generate energy for the manufacture of wood products in North America. Wood construction products have low embodied GHG emissions because they are grown using renewable solar energy, use little fossil fuel energy during manufacturing, and have many end-of-life options (reuse, recycle, energy recovery).

Wood products have the ability to substitute for other more carbon-intensive building materials and energy sources. GHG emissions are thereby avoided by using wood products instead of other more GHG-intensive building products. Displacement factors (kg CO2 avoided per kg wood used) have been estimated to calculate the amount of carbon avoided through the use of wood products in building construction.

 

For further information, refer to the following resources:

Addressing Climate Change in the Building Sector – Carbon Emissions Reductions (Canadian Wood Council)

Resilient and Adaptive Design Using Wood (Canadian Wood Council)

CWC Carbon Calculator

Canada’s Forest Products Industry “30 by 30” Climate Change Challenge (Forest Products Association of Canada)

www.naturallywood.com

www.thinkwood.com

Building with wood = Proactive climate protection (Binational Softwood Lumber Council and State University of New York)

Natural Resources Canada

Pan-Canadian Framework on Clean Growth and Climate Change (Government of Canada)

Intergovernmental Panel on Climate Change

Environmental product declarations (EPDs)

Stakeholders within the building design and construction community are increasingly being asked to include information in their decision-making processes that take into consideration potential environmental impacts. These stakeholders and interested parties expect unbiased product information that is consistent with current best practices and based on objective scientific analysis. In the future, building product purchasing decisions will likely require the type of environmental information provided by environmental product declarations (EPDs). In addition, green building rating systems, including LEED®, Green Globes™ and BREEAM®, recognize the value of EPDs for the assessment of potential environmental impacts of building products.

EPDs are concise, standardized, and third-party verified reports that describe the environmental performance of a product or a service. EPDs are able to identify and quantify the potential environmental impacts of a product or service throughout the various stages of its life cycle (resource extraction or harvest, processing, manufacturing, transportation, use, and end-of-life). EPDs, also known as Type III environmental product declarations, provide quantified environmental data using predetermined parameters that are based on internationally standardized approaches. EPDs for building products can help architects, designers, specifiers, and other purchasers better understand a product’s potential environmental impacts and sustainability attributes.

An EPD is a disclosure by a company or industry to make public the environmental data related to one or more of its products. EPDs are intended to help purchasers better understand a product’s environmental attributes in order for specifiers to make more informed decisions selecting products. The function of EPDs are somewhat analogous to nutrition labels on food packaging; their purpose is to clearly communicate, to the user, environmental data about products in a standardized format.

EPDs are information carriers that are intended to be a simple and user-friendly mechanism to disclose potential environmental impact information about a product within the marketplace. EPDs do not rank products or compare products to baselines or benchmarks. An EPD does not indicate whether or not certain environmental performance criteria have been met and does not address social and economic impacts of construction products.

Data reported in an EPD is collected using life cycle assessment (LCA), an internationally standardized scientific methodology. LCAs involve compiling an inventory of relevant energy and material inputs and environmental releases, and evaluating their potential impacts. It is also possible for EPDs to convey additional environmental information about a product that is outside the scope of LCA.

EPDs are primarily intended for business-to-business communication, although they can also be used for business-to-consumer communication. EPDs are developed based on the results of a life cycle assessment (LCA) study and must be compliant with the relevant product category rules (PCR), which are developed by a registered program operator. The PCR establishes the specific rules, requirements and guidelines for conducting an LCA and developing an EPD for one or more product categories.

The North American wood products industry has developed several industry wide EPDs, applicable to all the wood product manufacturers located across North America. These industry wide EPDs have obtained third-party verification from the Underwriters Laboratories Environment (ULE), an independent certification body. North American wood product EPDs provide industry average data for the following environmental metrics:

  • Global warming potential;
  • Acidification potential;
  • Eutrophication potential;
  • Ozone depletion potential;
  • Smog potential;
  • Primary energy consumption;
  • Material resources consumption; and
  • Non-hazardous waste generation.

Industry wide EPDs for wood products are business-to-business EPDs, covering a cradle-to-gate scope; from raw material harvest until the finished product is ready to leave the manufacturing facility. Due to the multitude of uses for wood products, the potential environmental impacts related to the delivery of the product to the customer, the use of the product, and the eventual end-of-life processes are excluded from the analysis.  

For further information, refer to the following resources:

ISO 21930 Sustainability in buildings and civil engineering works – Core rules for environmental product declarations of construction products and services

ISO 14025 Environmental labels and declarations – Type III environmental declarations – Principles and procedures

ISO/TS 14027 Environmental labels and declarations – Development of product category rules

ISO 14040 Environmental management – Life cycle assessment – Principles and framework

ISO 14044 Environmental management – Life cycle assessment – Requirements and guidelines

American Wood Council

Canada Green Building Council

Green Globes

BREEAM®

Construction products and the building sector as a whole have significant impacts on the environment. Policy instruments and market forces are increasingly pushing governments and businesses to document and report environmental impacts and track improvements. One tool that is available to help understand the environmental aspects related to new construction, renovation, and retrofits of buildings and civil engineering works is life cycle assessment (LCA). LCA is a decision-making tool that can help to identify design and construction approaches that yield improved environmental performance.

Several European jurisdictions, including Germany, Zurich and Brussels, have made LCA a mandatory requirement prior to issuing a building permit. In addition, the application of LCA to building design and materials selection is a component of green building rating systems. LCA can benefit manufacturers, architects, builders, and government agencies by providing quantitative information about potential environmental impacts and providing data to identify areas for improvement.

LCA is a performance-based approach to assessing the environmental aspects related to building design and construction. LCA can be used to understand the potential environmental impacts of a product or structure at every stage of its life; from resource extraction or raw material acquisition, transportation, processing and manufacturing, construction, operation, maintenance and renovation to the end-of-life.

LCA is an internationally accepted, science-based methodology which has existed in alternative forms since the 1960s. The requirements and guidance for conducting LCA has been established through international consensus standards; ISO 14040 and ISO 14044. LCA considers all input and output flows (materials, energy, resources) associated with a given product system and is an iterative procedure that includes goal and scope definition, inventory analysis, impact assessment, and interpretation.

The inventory analysis, also known as the life cycle inventory (LCI), consists of data collection and the tracking of all input and output flows within a product system. Publicly available LCI databases, such as the U.S. Life Cycle Inventory Database, are accessible free of charge in order to source this LCI data. During the impact assessment phase of the LCA, the LCI flows are translated into potential environmental impact categories using theoretical and empirical environmental modelling techniques. LCA is able to quantify potential environmental impacts and aspects of a product, such as:

  • Global warming potential;
  • Acidification potential;
  • Eutrophication potential;
  • Ozone depletion potential;
  • Smog potential;
  • Primary energy consumption;
  • Material resources consumption; and
  • Hazardous and non-hazardous waste generation.

LCA tools are available to building designers that are publicly accessible and user friendly. These tools allow designers to rapidly obtain potential environmental impact information for an extensive range of generic building assemblies or develop full building life cycle assessments on their own. LCA software offers building professionals powerful tools for calculating the potential life cycle impacts of building products or assemblies and performing environmental comparisons.

It is also possible to use LCA to perform objective comparisons between alternate materials, assemblies and whole buildings, measured over the respective life cycles and based on quantifiable environmental indicators. LCA enables comparison of the environmental trade-offs associated with choosing one material or design solution over another and, as a result, provides an effective basis for comparing relative environmental implications of alternative building design scenarios.

An LCA that examines alternative design options must ensure functional equivalence. Each design scenario considered, including the whole building, must meet building code requirements and offer a minimum level of technical performance or functional equivalence. For something as complex as a building, this means tracking and tallying the environmental inputs and outputs for the multitude of assemblies, subassemblies and components in each design option. The longevity of a building system also impacts the environmental performance. Wood buildings can remain in service for long periods of time if they are designed, built and maintained properly.

Numerous LCA studies worldwide have demonstrated that wood building products and systems can yield environmental advantages over other building materials and methods of construction. FPInnovations conducted a LCA of a four-storey building in Quebec constructed using cross-laminated timber (CLT). The study assessed how the CLT design would compare with a functionally equivalent concrete and steel building of the same floor area, and found improved environmental performance in two of six impact categories, and equivalent performance in the rest. In addition, at the end-of-life, bio-based products have the ability to become part of a subsequent product system when reused, recycled or recovered for energy; potentially reducing environmental impacts and contributing to the circular economy.

Life cycle of wood construction products


Photo source: CEI-Bois

For further information, refer to the following resources:

www.naturallywood.com

Athena Sustainable Materials Institute

Building for Environmental and Economic Sustainability (BEES)

FPInnovations. A Comparative Life Cycle Assessment of Two Multistory Residential Buildings: Cross-Laminated Timber vs. Concrete Slab and Column with Light Gauge Steel Walls, 2013.

American Wood Council

U.S. Life Cycle Inventory Database

ISO 14040 Environmental management – Life cycle assessment – Principles and framework

ISO 14044 Environmental management – Life cycle assessment – Requirements and guidelines

BUILDING CODES & STANDARDS (THE REGULATORY SYSTEM)

The construction industry is regulated through building codes which are informed by:

  • Design standards that provide information on “how to” build with wood,
  • Product standards that define the characteristics of the wood products that can be used in design standards, and
  • Test standards that set out the methodology for establishing a wood product’s characteristics

CWC is active in a technical capacity in all areas of the Regulatory System. This includes:

BUILDING CODES – CWC participates extensively in the development process of the Building Codes in Canada. CWC is a member of both National and Provincial Building Code Committees. These Committees are balanced and representation is limited to about 25 members on each Committee. Competing interests (i.e. steel and concrete) sit on the same Committees. This is an arena where CWC can win or lose ground for members’ products.

DESIGN STANDARDS – Each producer of structural materials develops engineering design standards that provide information on how to use their products in buildings. CWC holds the Secretariat for Canada’s wood design standard (CSA O86 “Engineering Design in Wood”), providing both technical expertise and administrative support for its development. CWC is also a member of the American Wood Council (AWC) committee that is responsible for the U.S. National Design Specification for wood design.

PRODUCT STANDARDS – CWC is involved in the development of Canadian, U.S. and international standards for its wood building product producers.

TEST STANDARDS – CWC is involved in developing Canadian, U.S. and international test standards in areas that affect wood products, such as fire performance.

Detailed building codes & standards pages:

With advanced construction technologies and modern mass timber products such as glued-laminated timber, cross-laminated timber and structural composite lumber, building tall with wood is not only achievable but already underway – with completed contemporary buildings in Australia, Austria, Switzerland, Germany, Norway and the United Kingdom at 9 storeys and taller. Increasingly recognized by the construction sector as an important, new, and safe construction choice, the reduced carbon footprint and embodied / operational energy performance of these buildings is appealing to communities that are committed to sustainable development and climate change mitigation.

Tall wood buildings, built with renewable wood products from sustainably managed forests, have the potential to revolutionize a construction industry increasingly focused on being part of the solution when it comes to urban intensification and environmental impact reduction. The Canadian wood product industry is committed to building on its natural advantage, through the development and demonstration of continuously improving wood-based building products and building systems.

A tall wood building is a building over six-storeys in height (top floor is higher than 18 m above grade) that utilizes mass timber elements as a functional component of its structural support system. With advanced construction technologies and modern mass timber products such as glued-laminated timber (glulam), cross-laminated timber (CLT) and structural composite lumber (SCL), building tall with wood is not only achievable but already underway – with completed contemporary buildings in Canada, US, Australia, Austria, Switzerland, Germany, Norway, Sweden, Italy and the United Kingdom at seven-storeys and taller.

Tall wood buildings incorporate modern fire suppression and protection systems, along with new technologies for acoustic and thermal performance. Tall wood buildings are commonly employed for residential, commercial and institutional occupancies.

Mass timber offers advantages such as improved dimensional stability and better fire performance during construction and occupancy. These new products are also prefabricated and offer tremendous opportunities to improve the speed of erection and quality of construction.

Some significant advantages of tall wood buildings include:

  • the ability to build higher in areas of poor soils, as the super structure and foundations are lighter compared to other building materials;
  • quieter to build on site, which means neighbours are less likely to complain and workers are not exposed to high levels of noise;
  • worker safety during construction can be improved with the ability to work off large mass timber floor plates;
  • prefabricated components manufactured to tight tolerances can reduce the duration of construction;
  • tight tolerances in the building structure and building envelope coupled with energy modelling can produce buildings with high operational energy performance, increased air tightness, better indoor air quality and improved human comfort

Design criteria for tall wood buildings that should be considered include: an integrated design, approvals and construction strategy, differential shrinkage between dissimilar materials, acoustic performance, behaviour under wind and seismic loads, fire performance (e.g., encapsulating the mass timber elements using gypsum), durability, and construction sequencing to reduce the exposure of wood to the elements.

It is important to ensure early involvement by a mass timber supplier that can provide design assistance services that can further reduce manufacturing costs through the optimization of the entire building system and not just individual elements. Even small contributions, in connection designs for example, can make a difference to the speed of erection and overall cost. In addition, mechanical and electrical trades should be invited in a design-assist role at the outset of the project. This allows for a more complete virtual model, additional prefabrication opportunities and quicker installation.

Recent case studies of modern tall wood buildings in Canada and around the world showcase the fact that wood is a viable solution for attaining a safe, cost-effective and high-performance tall building.

For more information, refer to the following case studies and references:

Brock Commons Tall Wood House (Canadian Wood Council)

Origine Point-aux-Lievres Ecocondos,Quebec City (Cecobois)

Wood Innovation and Design Centre (Canadian Wood Council)

Technical Guide for the Design and Construction of Tall Wood Buildings in Canada (FPInnovations)

Ontario’s Tall Wood Building Reference (Ministry of Natural Resources and Forestry & Ministry of Municipal Affairs)

Summary Report: Survey of International Tall Wood Buildings (Forestry Innovation Investment & Binational Softwood Lumber Council)

www.thinkwood.com/building-better/taller-buildings

When it comes to wood construction, many people think of basic 2×4 framing, panels or flooring for single-family homes. However, advances in wood science and building technology have resulted in stronger, more sophisticated and robust products that are expanding the options for wood construction, and providing more choices for builders and architects.

The Canadian Wood Council’s support for mid-rise construction is not unique In Ontario, Home Builders, through organizations such as RESCON, BILD and the Ontario Home Builders Association are also highlighting this opportunity.

  • Mid-rise buildings made of wood are a new construction option for builders. That’s good news for main-street Canada, where land is so expensive. The net benefit of reduced construction costs is increased affordability for home buyers.
  • In terms of new economic opportunity, the ability to move forward “now” creates new construction jobs in cities and supports employment in forestry communities. This also offers increased export opportunities for current and innovative wood products, where adoption in Canada provides the example for other countries.
  • This also reflects a new standard of engineering in that structural, fire and seismic concerns have all been addressed by the expert committees of the Canadian Commission on Building and Fire Codes.

In the end, when occupied, mid-rise buildings fully meet the same requirements of the Building Code as any other type of construction from the perspective of health, safety and accessibility.

 

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