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®

Annual Review Rules and Form EPD

Wood structures, properly designed and properly treated, will last indefinitely. This section includes guidance on specific applications of structures that have constant exposure to the elements.

Mass timber exteriors

Modern Mass Timber Construction includes building systems otherwise known as post-and-beam, or heavy-timber, and cross laminated timber (CLT). Typical components include solid sawn timbers, glue-laminated timbers (glulam), parallel strand lumber (PSL) laminated veneer lumber (LVL) laminated strand (LSL), and CLT. Heavy-timber post and beam with infill walls of various materials is one of the oldest construction systems known to man. Historic examples still standing range from Europe through Asia to the long-houses of the Pacific Coastal first nations (Figure 1). Ancient temples in Japan and China dating back thousands of years are basically heavy timber construction with some components semi-exposed to the weather (Figure 2). Heavy-timber-frame warehouses with masonry walls dating back 100 years or more are still serviceable and sought-after as residences or office buildings in cities like Toronto, Montreal and Vancouver (Koo 2013). Besides their historic value, these old warehouses offer visually impressive wood structures, open plan floors and resultant flexibility of use and repurposing. Building on this legacy, modern mass timber construction is becoming increasingly popular in parts of Canada and the USA for non-residential construction, recreational properties and even multi-unit residential buildings. Owners and architects typically see a need to express these structural materials, particularly glulam, on the exterior of the building where they are at semi-exposed to the elements (Figure 3). In addition wood components are being increasingly used to soften the exterior look of non-wood buildings and make them more appealing (Figure 4). They are anticipated to remain structurally sound and visually appealing for the service life. However, putting wood outside creates a risk of deterioration that needs to be managed. Similar to wood used for landscaping, the major challenges to wood in these situations are decay, weathering and black-stain fungi. This document provides assistance to architects and specifiers in making the right decisions to maximize the durability and minimize maintenance requirements for glulam and other mass timber on the outside of residential and non-residential buildings. It focusses on general principles, rather than providing detailed recommendations. This is primarily focussed on a Canadian and secondarily on a North American audience.

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Disaster Relief Housing

Shelter needs after natural disasters come in three phases:

1. Immediate shelter: normally supplied by tarpaulins or light tents
2. Transition shelter: may be heavy-duty tents or more robust medium-term shelters.
3. Permanent buildings: Ultimately permanent shelters need to be constructed when the local economy recovers.

Immediate and transition shelters are typically supplied by aid agencies. Light wood frame is ideal for rapid provision of medium- to long-term shelter after natural disasters. However, there are challenges in certain climates for wood frame construction that must be addressed in order to sustainably and responsibly build them. For example, many of the regions which experience hurricanes, earthquakes and tsunamis also have severe decay and termite hazards including aggressive Coptotermes species and drywood termites. In extreme northern climates, high occupancy loads are common and when combined with the need for substantial thermal insulation to ensure comfortable indoor temperatures, can result in condensation and mould growth if wall and roof systems are not carefully designed.

The desire of aid organizations to maximize the number of shelters delivered tends to drive down the allowable cost dictating simplified designs with fewer moisture management features. It may also be difficult to control the quality of construction in some regions. Once built, “temporary” structures are commonly used for much longer than their design life. Occupier improvements over the longer term can potentially increase moisture and termite problems. All of these factors mean that the wood used needs to be durable.

One method of achieving more durable wood products is by treating the wood to prevent decay and insect/termite attack. However, commonly available preservative treated wood in Canada may not be suitable for use in other countries. Selection of the preservative and treatment process must take into account the regulations in both the exporting and receiving countries, including consideration of the potential for human contact with the preserved wood, where the product will be within the building design, the treatability of wood species, and the local decay and termite hazard. Simple design features, such as ensuring wood does not come into contact with the ground and is protected from rain, can reduce moisture and termite problems.

Building with concrete and steel does not eliminate termite problems. Termites will happily forage in a concrete or masonry block buildings looking for wood components, furniture, cupboards, and other cellulosic materials, such as the paper on drywall, cardboard boxes, books etc. Mud tubes running 10ft over concrete foundations to reach cellulosic building materials have been documented. Indeed, termites have caused major economic damage to cellulosic building materials even in concrete and steel high-rises in Florida and in southern China.

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Timber bridges

Timber bridges are an excellent way to showcase the strength and durability of wood structures, even under harsh conditions, when material selection, design, construction and maintenance are done well. They could also be critical infrastructure elements that span fast rivers or deep gorges. Consequences of failure of these structures can be severe in loss of life and loss of access to communities. Durability is as critical as engineering to ensure safe use of timber bridges for the design life, typically 75 years in North America.

There are numerous examples of old wood bridges still in service in North America (Figure 1). The oldest are traditional covered bridges (Figure 2), three of which are around 190 years old. In Southeast China, Fujian and Zhejiang provinces have numerous covered bridges that are almost 1000 years old (Figure 3). The fact that these bridges are still standing is a testament to the craftsmen that selected the materials, designed the structures, built them, monitored their condition and kept them maintained and repaired. They would have selected the most durable wood species available, likely Chestnut or cedars in North America, china fir (china cedar) in southeast China. They would have adzed off the thin perishable sapwood exposing only the naturally durable heartwood. The fact the covered bridges around today all look similar is because those were the tried and tested designs that worked. They clearly designed those bridges to shed water with a wood shingle roof, vertical siding projecting below the deck and structural elements sheltered from all but the worst wind-driven rain. Any rain that did not drip off the bottom of the vertical siding and wicked up the end grain would also dry out reasonably rapidly. Slow decay that did occur at the bottom of these boards was inconsequential because it was remote from connections to structural elements. Construction must have been meticulously performed by experienced craftsmen. Those craftsmen may well have been locals that would continue to monitor the bridge over its life and make any repairs necessary. Of course, not every component in those ancient bridges is original, particularly shingle roofs that typically last 20-30 years depending on climate. These bridges have all been repaired due to decay and in some cases dismantled and re-built over the years for various reasons (e.g., due to changes in traffic loads, arson, flooding, fire, hurricanes, etc.). The Wan’an Bridge in Fujian is known to have been built in 1090, refaced in 1708 and rebuilt in 1845, 1932 and 1953. The apparently increasing frequency of rebuilding may suggest a loss of knowledge and skills, but all repairs and reconstruction prior to 1845 may not have been recorded.

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Permanent Wood Foundations

A permanent wood foundation (PWF) is a strong, durable and proven construction method that has a number of unique advantages over other foundation systems for both the builder and the homeowner. The first Canadian examples were built as early as 1950 and are still being used today. PWFs can also be designed for projects such as crawl spaces, room additions and knee-wall foundations for garages and mobile homes. Concrete slab-on-grade, wood sleeper floors and suspended wood floors can all be used with PWFs.

A permanent wood foundation is an in-ground engineered construction system designed to turn a home’s foundation into useable living space. A below-grade stud wall constructed of preservative treated plywood and lumber supports the structure and encloses the living space. PWFs are suitable for all types of light-frame construction covered under Part 9 (Housing and Small Buildings) of the National Building Code of Canada, under clauses 9.15.2.4.(1) and 9.16.5.1.(1). This includes single-family detached houses, townhouses, low-rise apartments, and institutional and commercial buildings. In addition, the recently revised CSA S406 standard, Specification of permanent wood foundations for housing and small buildings, allows for three-storey construction supported by PWF.

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Choosing a coating depends on what appearance is desired and what level of maintenance would be tolerable.  For many people, the basic choice is paint versus stain. The trade-off is often between maintenance frequency and appearance.

For many people, additional criteria include VOC emissions, ease of clean up, and cost.  See our Links page for web sites and books with detailed information on choosing and applying wood finishes.  Read our About exterior wood coatings page for an understanding of the differences between paints and stains, pigmented versus clear coatings, and so forth.

Because exterior wood shrinks and swells with moisture changes, the coating needs to be flexible. Flexibility varies by product – some products may be clearly identified as suitably flexible for wood’s dimensional changes.  Water-borne coatings are generally more flexible than alkyds. Coatings containing urethanes tend to be more flexible than coatings containing acrylics.

For factory finishing with transparent coatings, with special considerations for UV and mildew control, please see our fact sheet Factory Finishing with Transparent Coatings: Requirements for Maximizing Longevity.

Special Considerations

If a coating is desired for a wear surface such as a deck or stairs, consult carefully with the coating manufacturer to choose the right product for this demanding application.  All coatings will be challenged by foot traffic and increased exposure to weather in a horizontal application.  High traffic routes will show wear faster than other areas. Paints and other thick film-formers may fail quickly in this situation, and a time-consuming refinishing process will be necessary each time the coating fails.  Hence many people will find a stain the more convenient choice for decks and stairs.

Knots may require a bit of extra care as some wood extractives or resin may leach out or bleed. Extractive bleeding can cause discolouration, but this can usually be prevented by applying special stain-blocking primers. In some species, especially the pines and Douglas-fir, knots and pitch pockets contain resin. The resin can bleed and may discolour the finish, leave hard beads of resin on the surface, or may otherwise interfere with the coating bond. The best way to prevent this is to purchase kiln-dried wood where the resin should be set (hardened and fixed in place). If painting is desired, choose higher grades of lumber as these will have fewer knots, and choose kiln-dried lumber if using a resinous species.

If siding or sidewall shingles are to be painted, the US Forest Products Laboratory (USFPL) recommends they be backprimed.  This application of a coating to the back side will plug the wood pores, preventing extractive bleed without blocking water vapour transmission and also preventing liquid water uptake.

If possible, round out any sharp corners for best coating adhesion on these edges – for example, a square-edged stair tread will show coating degradation quickly, but bullnosed stair tread edges will retain a coating much longer.  This is because a coating applied to a corner tends to pull away from the corner, leaving a much thinner layer there than elsewhere.

For new wood, remember:

• The wood must be dry.  Drying time depends on a few factors.
  • Ideally the wood should be kiln-dried (stamped “S-DRY”, “KD” or “KDAT”, see glossary of “dry lumber”). If the wood is surface wet from rain or washing, let dry 1 to 2 days.
  • If the wood is wet through (green lumber, pressure-treated lumber not stamped “KDAT”), 2 days of drying is acceptable if using a “damp-friendly” coating.  Otherwise:
  • The wood must be allowed to thoroughly dry to a stable outdoor moisture content; about 15% in most climates. The characteristics of the wood and the climatic characteristics of its environment are so variable that drying time is hard to predict.  The common way to determine wood moisture content is with a moisture meter. (Note: specific correction factors should be applied if a moisture meter is used on preservative-treated wood.)
• Weather conditions during coating application can affect the coating’s drying, appearance and performance. Follow the coating manufacturer’s recommendation.
• Coat as soon as possible after the wood has been planed or sanded.  Apply finishes within two weeks of exposure, or sooner if possible (Surface Preparation for Fresh Wood).  Otherwise, follow the instructions for aged (weathered) wood below.
• If the wood is very smooth, lightly sand it to roughen the surface with 100-120 grit sand paper.  This greatly improves the coating bond.  Brush free of dirt and sawdust.
• If painting the wood, apply a primer coat. Use an extractive-blocking primer, if needed (for example, with western red cedar or redwood) over the entire piece, or a knot sealing primer if needed (Special Considerations).  When dry, apply two coats of top quality paint. For stains and water repellents, follow the  instructions on the can regarding number of coats.
• Carefully follow the instructions on the can regarding best environmental conditions for coating, application recommendations, safety precautions and clean-up.

For aged (weathered) wood, remember:

• For wood that has been previously coated, please read about refinishing.
• Clean the wood and remove discolourations such as iron stain, if desired.  Expose fresh wood because coatings perform best when applied to freshly exposed wood surfaces.  Allow to dry. See Surface Preparation for Aged Wood.
• Brush free of dirt and sawdust, and proceed with application of the coating.

When maintaining or refinishing, remember:

• Avoid the need to refinish by keeping an eye on the coating and adding a fresh coat before the previous coat wears away, cracks or peels.  This may be as frequent as every six months with water repellents, every year or two with stains, and every few years with paint (See Maintenance).
• Spot-treat worn areas to extend the period between full applications of a fresh coat.  Sand away any failed coating and any weathered wood, and re-apply the coating (See Maintenance).
• If the coating has failed on a large scale, or the coating is getting too thick for refinishing, or if a change in type of coating is desired, completely strip away the old coating – please read about refinishing.

The treated wood you buy at your local building supplies store will have an end tag to help you choose the right product. The tag identifies the type of preservative used, the amount retained, the appropriate use for this piece of wood, and the treatment plant name and location. The most important information to look for is the use class. If the piece is going in the ground (e.g. a fence post), you need the piece to be treated for “ground contact.” All other uses (such as fence boards, deck boards and shingles) can be labeled “above ground.” The piece may also be tagged with consumer safety information. You might also find this information in the store, either posted or as a technical brochure.

The National Building Code of Canada (NBC) contains requirements regarding the use of treated wood in buildings and the CSA O80 Series of standards is referenced in the NBC and in provincial building codes for the specification of preservative treatment of a broad range of wood products used in different applications. The first edition of CSA O80 was published in 1954, with eleven subsequent revisions and updates to the standard, with the most recent edition published in 2015.

The manufacture and application of wood preservatives are governed by the CSA O80 Series of standards. These consensus-based standards indicate the wood species that may be treated, the allowable preservatives and the retention and penetration of preservative in the wood that must be achieved for the use category or application. The CSA O80 Series of standards also specifies requirements related to the fire retardance of wood through chemical treatment using both pressure and thermal impregnation of wood. The overarching subjects covered in the CSA O80 Series of standards also include materials and their analysis, pressure and thermal impregnation procedures, and fabrication and installation.

Canadian standards for wood preservation are based on the American Wood Protection Association (AWPA) standards, modified for Canadian conditions. Only wood preservatives registered by the Canadian Pest Management Regulatory Agency are listed.

The required preservative penetrations and loadings (retentions) vary according to the exposure conditions a product is likely to encounter during its service life. Each type of preservative has distinct advantages and the preservative used should be determined by the end use of the material.

Processing and treating requirements in the CSA O80 Series are designed to assess the exposure conditions which pressure treated wood will be subjected to during the service life of a product. The level of protection required is determined by hazard exposure (e.g., climatic conditions, direct ground contact or exposure to salt water), the expectations of the installed product (e.g., level of structural integrity throughout the service life) and the potential costs of repair or replacement over the life cycle.

The technical requirements of CSA O80 are organized in the Use Category System (UCS). The UCS is designed to facilitate selection of the appropriate wood species, preservative, penetration, and retention (loading) by the specifier and user of treated wood by more accurately matching the species, preservative, penetration, and retention for typical moisture conditions and wood biodeterioration agents to the intended end use.

The CSA O80.1 Standard specifies the following Use Categories (UC) for treated wood used in construction:

• UC1 covers treated wood used in dry interior construction;
• UC2 covers treated wood and wood-based materials used in dry interior construction that are not in contact with the ground but can be exposed to dampness;
• UC3 covers treated wood used in exterior construction that is not in ground contact;
  • UC3.1 covers exterior, above ground construction with coated wood products and rapid run off of water;
  • UC3.2 covers exterior, above ground construction with uncoated wood products or poor run off of water;
• UC4 covers treated wood used in exterior construction that is in ground or freshwater contact;
  • UC4.1 covers non-critical components;
  • UC4.2 covers critical structural components or components that are difficult to replace;
• UC5A covers treated wood used in Coastal waters including; brackish water, salt water and adjacent mud zone.

This CSA O80 Series of standards consists of the following standards, as follows:

1. CSA O80.0 General requirements for wood preservation; specifies requirements and provides information applicable to the entire series of standards.
2. CSA O80.1 Specification of treated wood; is intended to help specifiers and users of treated wood products identify appropriate requirements for preservatives for various wood products and end use environments.
3. CSA O80.2 Processing and treatment; specifies minimum requirements and process limitations for treating wood products.
4. CSA O80.3 Preservative formulations; specifies requirements for preservatives not referenced elsewhere.
5. CSA O80.4 has been withdrawn.
6. CSA O80.5 CCA Additives — Utility Poles; specifies requirements for preparation and use of CCA preservative/additive combinations for utility poles permitted by CSA O80.1 and CSA O80.2.

For further information, refer to the following resources:

www.durable-wood.com

CSA O80 Wood preservation

Wood Preservation Canada

National Building Code of Canada

Pest Management Regulatory Agency

American Wood Protection Association

ISO 21887 Durability of wood and wood-based products — Use classes

Click here for more information on performance tests done with treated wood.

Canada has had a wood preservation industry for about 100 years.  Canada is tied with the UK as the world’s second largest producer of treated wood (the USA is first, by a large margin).  In 1999, the most recent year for which we have data, Canada produced 3.5 million cubic metres of treated wood.  There are about 65 treating plants in Canada.

As with most other industrialized countries, Canada developed a wood preservation industry using creosote, initially to service railroads (the ties holding the rails) and then utilities (power poles).  Creosote production began declining by the 1950s, and by the 1970s was being somewhat replaced for these traditional uses by pentachlorophenol.  Today, these oil-borne preservatives only constitute 17% of Canadian treated wood production.

The remaining 83% of production uses water-borne preservatives such as CCA, ACQ and CA.  The industry began its substantial shift to the water-borne products in the 1970s, as consumer interest in decks and other residential outdoor structures dramatically increased.  For many years, CCA was by far the dominant preservative for both residential and industrial applications.

In 2004, CCA regulations were changed such that CCA is no longer available for many residential applications.  Subsequently, Canadian treaters have shifted about 80% of their previous CCA production to ACQ or CA.

Most of Canada’s treated wood is used domestically; Canada exports only 10% of its production.

Canada has its own wood preservation standards, supports several technical and marketing organizations, and maintains a lead position in certain areas of wood preservation research.  A major focus of the industry has been in response to increasing levels of health and environmental protection regulations.

FPInnovations has been field testing the performance of treated wood products for years. Click one of these categories for performance data from our field tests.

Borate-treated Wood vs. Termites

Naturally Durable Species

The heartwood of species reported to have some natural durability was evaluated in ground contact (stakes) and above-ground (decking) tests. 

Commodity: 2×4 and 2×6 lumber from naturally durable species: Western redcedar, yellow cypress, eastern white cedar, larch, tamarack, Douglas-fir

Control species: Ponderosa pine sapwood

Test method: Stake test (AWPA E7) and Decking test (AWPA E25)

Test sites: FPInnovations – Maple Ridge, BC; Petawawa, ON

Michigan Technological University – Gainesville, Florida; Kipuka, Hawaii 

Date of installation: 2004-2005

Estimated service life: In the ground-contact stake test, after 5 years moderate to high levels of decay were found in all species at all sites. Yellow cypress and western redcedar were the most durable at all site. Eastern white cedar had similar durability at the Canadian and Florida sites, but was less durable in Hawaii. There were no major performance differences observed between old-growth and second-growth materials used in this study. Untreated naturally durable heartwood is not recommended for long-term performance in ground contact.

In the above ground decking test, at the Canadian test sites after 10 years only small amounts of decay were observed in any of the naturally durable heartwoods tested. In contrast, the ponderosa pine controls had moderate to advanced decay. Decay was more rapid at the Florida and Hawaii test sites, with moderate to advanced decay present in all material types after 7 years. Untreated naturally durable heartwood is not recommended for long-term performance in exposed above ground applications in high decay hazard areas such as Florida and Hawaii. However, in temperate climates these naturally durable heartwoods can provide service lives greater than 10 years.

References:

Morris, P. I., Ingram, J., Larkin, G., & Laks, P. (2011). Field tests of naturally durable species. Forest Products Journal, 61(5), 344-351.

Morris, P. I., Laks, P., Larkin, G., Ingram, J. K., & Stirling, R. (2016). Aboveground decay resistance of selected Canadian softwoods at four test sites after 10 years of exposure. Forest products journal, 66(5), 268-273.

There’s no reason a wood structure can’t last virtually forever – or, at least hundreds of years, far longer than we may actually need the building. With a good understanding of how to protect wood from decay and fire, we can expect today’s wood buildings to be around for as long as we wish.

While wood does not have the historical longevity of stone, there nonetheless remain standing some very old wood buildings. In Europe, wood was long a dominant building material dating back to the beginning of civilisation. Most of these ancient buildings are long gone, lost to fire, decay, or deconstruction for another purpose. In the early days of wood construction, the primary structural components were placed directly in the ground, which eventually leads to decay. It was not until sometime in the 1100s that builders began to use stone footings – thus our still-standing examples of wood buildings generally date from no earlier than that time.

Perhaps the most famous ancient European wood buildings still in evidence today are the Norwegian stave churches, hundreds of which were built in the 12th and 13th centuries and of which 25-30 still remain today. Their exterior claddings have typically been replaced, but the structural wood is original.

In North America, the abundance of wood and the existing timber skills of early settlers led to widespread use of wood – wood has always been and still is the primary structural material for small buildings here. The oldest surviving wood homes in the US date to the early 1600s. Nearly 80 homes remain from this era in the New England states.

Many other North American wood buildings survive from the 18th century. Even in the demanding climate of Louisiana, where hot and humid conditions present a challenge for wood durability, one can still find some of the original French settlements dating to the first half of the 1700s. And of course, there are countless standing wood buildings from the 1800s and early 1900s, most of which are probably still occupied.

Japan has a well-known history of wood use and is the home of the oldest surviving wood structure in the world, a Buddhist temple near the ancient capital city of Nara. The Horyu-ji temple is believed to have been built at the beginning of the eighth century (c. 711) and possibly even earlier, as one of the hinoki (Japanese cypress) posts appears to have been felled in the year 594. This temple’s longevity is largely helped by careful maintenance and repair. This entire region of Japan has many other ancient wood buildings still standing.

For modern buildings, we don’t normally require such exceptional longevity. The life of a typical North American house is no more than 100 years (the average is lower), and our non-residential buildings are usually demolished in 50 years or less. Wood is perfectly suitable for these lifetime expectations. Click here for survey data showing that wood buildings last as long, or longer than buildings made of other materials.

Irving House is a large, one and one-half storey plus basement wood-frame residence, designed in the Gothic Revival style, located on its original site at the corner of Royal Avenue and Merivale Street in the New Westminster neighbourhood of Albert Crescent. Irving House is remarkable for the extent to which its original exterior and interior elements have been maintained. Operated as an historic house museum, it also includes a collection of many original furnishings from the Irving family.

By courtesy of New Westminster Museum and Archives, New Westminster, British Columbia

Other link: http://www.flickr.com/photos/bobkh/297751638/in/set-72157594340707368/

1912 House, Vancouver BC

This classic turn-of-the-century home was slated for demolition in 1990. It was already stripped back to the bare framing when it was purchased by a new owner who wished to convert it into apartments. At the new owner’s request, the building was inspected by Dr. Paul Morris of Forintek in 1991 for signs of deterioration. After 80 years in service there were no signs of decay on any of the framing members nor the window frames, most of which were original.

Temple at Nara, Japan

The Horyuji Buddhist temple at Nara is probably the oldest wooden structure in the world. Nara became the first permanent capital of Japan in 710.