This document discusses the life cycle impacts of different building materials. It notes that while most environmental impacts from materials occur during extraction and production, they continue to influence the building's footprint throughout its operational lifespan and beyond. It then provides an overview of the topics that will be covered, including the durability, energy usage, recycling potential, and code considerations of wood, concrete, and steel materials. The document outlines its learning objectives and includes a table of contents for the presentation.

1. When an architect specifies a building
material, that choice casts a long shadow.
While most of the environmental effects
from materials occur during the extraction
and production phases, they continue to
influence a structures environmental
footprint long afterwards, throughout the
operations phase and beyond.
Materials
in Action
Building Materials:
Construction,
Operational and End of
Life Impacts
(Part 2 of a 3-part series)
PhotobyNicLehoux,courtesyofBingThomArchitect

2. This presentation is part two in a three-part series, based on a CEU, Materials in Action, first published in Architectural
Record in 2011. Some of the statistics have been updated based on new information.
• Materials Matter (Part 1 of 3) documents the environmental footprint of wood, concrete and steel.
• Materials in Action (Part 2 of 3) covers their performance during construction, operation and end-of-life, reaffirming
that, in the quest for carbon-neutral buildings, materials do matter.
• A Natural Choice (Part 3 of 3) examines how these materials factor into green design and high-performance buildings
as well as how green design projects are currently defined.
This presentation covers the differences between wood, steel and concrete in terms of basic material properties, as well
as their performance during the building operations phase, and end-of-life impacts.
Materials Matter Series Overview
Materials Matter (Part 1) Materials in Action (Part 2)
A Natural Choice (Part 3)

3. Copyright Materials
This presentation is protected by U.S. and international copyright laws.
Reproduction, distribution, display and use of the presentation without
written permission of reThink Wood is prohibited.
© 2013, reThink Wood, www.rethinkwood.com

4. More specifically, topics covered will include durability and adaptability, the
difference between embodied and operational energy and their associated
impacts, opportunities for recycling and reuse, and the evolution of building
codes as related to wood construction.
Learning Objectives
 Evaluate the durability and versatility of wood, concrete and steel.
 Explain how current building codes permit the extended use of wood.
 Articulate the importance of embodied and operating energy.
 Discuss a building material’s end-of-life issues.
Photo Source (in order): naturallywood.com, dreamstime, dreamstime

5. Table of Contents
Section 1
Design
Considerations
Section 2
Materials in the
Construction
Phase
Section 3
Materials in the
Use Phase
Section 4
End of Use –
Closer Look at
Recycling & Reuse
Section 5
Evolving Building
Codes

6. DESIGN CONSIDERATIONS
SECTION 1

7. To understand a material’s true
impacts, it needs to be
considered over its life cycle.
How durable is it? Is the material
thermally efficient? Is it
susceptible to moisture damage?
Can it withstand seismic activity?
What are the code
considerations? Can it be
recycled or reused and, if yes, at
what cost to the environment?
These are the kinds of questions
that should be considered in the
earliest project phases. The
answers will determine, in part,
a structure’s sustainability
quotient.
Consider the Impacts of Materials
Sustainability
Quotient
• Life cycle impacts
• Durability
• Thermal efficiency
• Susceptibility to moisture
• Seismic performance
• Codes and regulations
• Recycling/reuse …
at what cost?

8. While durability is a common goal of green
building, adaptability is also important.
For this project in the Pacific Northwest,
protecting wood from moisture was a
priority. The yellow exterior sheathing is
mold-resistant drywall. It was used as an
exterior substrate, onto which the weather-
resistant barrier and cladding were
attached.
University of Washington West Campus Student
Housing
Washington
Architect: Mahlum
Durability & Adaptability
Photo: W.G. Clark Construction

9. Good design and quality
construction are key to
a building’s longevity, as
is maintenance. Any
building of wood,
concrete or steel could
last an indefinite period
of time, providing it is
properly maintained.
This all-wood pagoda—
which still exists
today—was built in
1056. It’s about as high
as an 18-story office
building.
Photo: wikipedia
Sakayamuni Pagoda
 Built in 1056, China’s oldest
all-wood pagoda
 About as tall as an 18-story
office tower (221 ft or 67.31 m)
 Has survived several major
earthquakes
 So famous it has the nickname
"Muta” (木塔)—literally, "Timber
Pagoda”
Wood Buildings Can
Last Centuries

10. Moisture control is critical for all buildings. Without it, concrete will spall, steel will rust and wood will decay.
The most effective and common way to prevent or slow these effects is to eliminate contact with water, either by coatings or protection within the building envelope.
In the case of lumber, grading rules and many building codes require that wood be dried to 19 percent moisture content. This is well below the fiber saturation point of 28 percent, the level at
which mold or decay can begin to thrive. Adverse effects are also prevented by avoiding direct contact between untreated wood and the ground or other moisture sources or, where this isn’t
possible, using preservative treated wood.
Bulk water, air infiltration and condensation can be a source of moisture in all types of buildings. However, while wood acts as a thermal break due to its inherent insulating properties, steel,
concrete and masonry are thermal bridges ... which can provide a cold surface on which warm, moist air can condensate. This increases the possibility for deterioration and mold.
A study by FPInnovations (then Forintek) showed that interior wood paneling can reduce peak moisture loads in a typical Canadian house by 10 to 25 percent—a scenario that leads to both
improved user comfort and reduced need for air conditioning.
Study reference: Potential for hydroscopic building materials to improve indoor comfort and air quality in the Canadian climate; C. Simonson, S. Olutimayin, M. Salonvaara, T. Ojanen, and J.
O’Connor, Performance of Exterior Envelopes of Whole Buildings IX, December 2004
Moisture is a Challenge for Most Materials
In all cases, proper maintenance and moisture control are CRITICAL.
Steel Concrete Wood
Rust, corrosion Spalling, cracking, rebar exposure Fungi and mold
Causes: constant wetting, high
humidity, dilute acids, salts, sea air
Causes: constant wetting, high
humidity, dilute acids, salts, sea air
Causes: constant wetting

11. For wood buildings, there are four
key steps to designing for durability
...
1. Protect materials from moisture.
2. Prevent insect infestation.
3. Use durable materials.
4. Maintain quality through good
construction practices.
The building in this photo is the
Percy Norman Aquatic Centre in
British Columbia, which features a
solid wood roof supported on
Douglas-fir glulam beams that
span up to 130 feet (43 metres)
across the main pool area. The
facility was built for the 2010
Winter Olympic Games and
designed to achieve LEED Gold
certification. Because wood
tolerates high humidity and is
capable of absorbing and
releasing water vapour without
compromising its structural
integrity, it is well suited to the
demanding atmosphere found in
swimming pools and ice rinks.
1. Protect materials from moisture.
2. Prevent insect infestation with
soil/foundation barriers and bait
systems.
3. Use durable species or treated
wood in areas prone to constant
wetting.
4. Maintain quality assurance with
good construction practices,
frequent inspections and reporting.
Design for Durability
Percy Norman Aquatic Centre
British Columbia
Architect: Hughes Condon Marler
LEED Gold
Photo: naturallywood.com

12. At the same time, while durability is crucial to the design of any building, designers should be aware that most buildings are demolished long before the end of their
useful service lives—for reasons that have nothing to do with the structural material.
Historically, many building industry professionals believed that use of materials perceived as more ‘durable,’ such as steel and concrete, would result in buildings with
longer service lives than wood buildings. However, a survey of buildings demolished between 2000 and 2003 in the Minneapolis/St. Paul area demonstrated that there
is no significant relationship between the structural system used and the actual life of the building. Reasons for demolition were instead related to changing land values,
lack of suitability of the building for current needs, and lack of maintenance of various non-structural components.
Source: Survey on Actual Service Lives for North American Buildings, 2004, FPInnovations
Although it is often believed that ‘durable’
structural materials such as steel and concrete
will provide the longest service lives for their
buildings, our results suggest there is no
significant relationship between the structural
system and the actual useful life of the building.
-- Survey on Actual Service Lives for North American Buildings
FPInnovations
Durability vs. Service Life
“
“

13. Overall, wood buildings in the study had the longest life spans. Sixty-three percent were older than 50
years at demolition and the majority were older than 75 years. By comparison, over half of the
demolished concrete buildings fell into the 26-50 year category and only one third of the concrete
buildings lasted more than 50 years. Similarly, 80 percent of the steel buildings demolished fell below the
50-year mark, and half of those were no older than 25 years.
This data shows two things ...
1) Wood structural systems are fully capable of meeting a building’s longevity expectations.
2) When you consider the embodied energy and other impacts associated with demolished buildings, the
fact that wood is adaptable—either through renovation or deconstruction and reuse—is a significant
advantage.
Source of data: Survey on Actual Service Lives for North American Buildings, 2004, FPInnovations
Source of graphic: Tackle Climate Change: Use Wood (book)
Service Life of Actual Buildings
 The service lives of
most buildings are
likely far shorter than
their theoretical
maximum.
 The majority of
demolished steel and
concrete buildings in
the study were less
than 50 years old.

14. Because of the unpredictability of future building needs, many experts advise
that, instead of trying to design structures with infinite life spans, designing
buildings that lend themselves to renovation or adaptation is a good way to
extend their lives and reduce waste. Wood is particularly versatile and flexible,
which makes it an easy construction material for renovations. For example,
Ardencraig House in Vancouver, British Columbia, comprises four town homes
designed within the framework of an existing heritage home and garage. Over
90 percent of the wood in the original structure was retained in adapting the
house. Salvaged materials from deconstruction of the garage were also used to
construct a coach house behind the main building. Salvaged framing members
were used to strengthen roof trusses and increase the space available for
insulation.
Longer Life Through Adaptation:
90% of the original wood structure retained
Salvaged wood was used extensively in the adaptation
of four town homes in Vancouver.

15. The strength of a building material refers to its ability to withstand an applied load without failure. Several types of load can be applied—tension,
compression, torsion, bending and shearing.
Steel is one of the strongest materials for tensile strength, which is the amount of stretching it can take before breaking or failing. It is also one of the
few materials that is equally strong in tension and compression.
Concrete is one of the strongest materials for compressive strength; tremendous loads can be put on concrete without crushing it. However, concrete
doesn’t have the same advantage when it comes to tensile strength. In building construction, rebar (or reinforcing steel bars) provides the tensile
strength lacking in concrete. Concrete also has a very low coefficient of thermal expansion, which means that it shrinks as it matures. All concrete
structures will crack to some extent, due to shrinkage and tension.
Terminal 2 at the Raleigh-Durham International Airport features a stunning and innovative timber roof system. Designers envisioned a seamless rolling
roof line—which required a combination of large wood and steel members to achieve. A hybrid structural system was created featuring lenticular,
long-span king post trusses built from glulam members, steel sections, and locked coil cable tension chords. The major challenge was to
develop a connection design to handle significant forces at the steel wood joints, while maintaining a clean, craftsman-like appearance. The
result is a system in which the connection mechanisms are nearly invisible, fitting seamlessly into the wood.
Terminal 2, Raleigh-Durham International Airport
North Carolina
Architect: Fentress Architects
Strength
Photo: Nick Merrick @ Hedrich Blessing, courtesy Equilibrium

16. Wood’s strength is dependent on loading
direction. It is strongest in tension along the
fibers and weakest in radial and tangential
directions. When loaded longitudinally along
the grain, wood can have a strength-to-weight
ratio advantage relative to steel of 2:1.
However, when wood is loaded in other
directions, including radial and tangential to
the grain, this advantage disappears.
Wood’s strength also varies significantly by
species.
The photo in this slide is the Branson
Convention Center, which shares
amenities with the Branson Hilton hotel.
The salient feature of the building is a
sweeping concourse of heavy timber
construction that recalls the natural context
of the Ozarks.
Timber posts provide lateral support for
the 25-foot tall curtain wall. Exposed heavy
timber decking forms the roof and finished
ceiling of the structure. The decking is
supported on glulam roof beams, and
sloping V-braces—made from 15-inch
diameter circular timber columns—support
the glulam beams, which span up to 80
feet.
Sources for 2:1 stat:
Ho Chi Min University:
http://www4.hcmut.edu.vn/~dantn/Matter/W
ood.html
Roy Mech engineering website:
http://www.roymech.co.uk/Useful_Tables/Ma
tter/Wood.html
Wood: The Designer’s Choice
 Strength depends on load direction.
 Every species has its own strength
characteristics and applications.
Branson Convention Center
Missouri
Architect: tvsdesign
Photos: Brian Gassel, tvsdesign

17. Wood is also an excellent choice for use with other
materials—as illustrated by the photos shown here. The
200,000-square-foot Arena Stage at the Mead Center
for American Theater has 18 Douglas-fir parallel
strand lumber columns that go as high as 56 feet to
support the roof’s steel trusses, girders and rafters.
The Pocono Environmental Education Center makes use of
wood and concrete. Note that wood has been used in both
cases to add architectural drama and visual warmth.
Wood complements other
materials while expanding
design options.
Pocono Environmental Education Center
Pennsylvania
Architect: Bohlin Cywinski Jackson
Leveraging Structural
Properties
Steel
+
Wood
Concrete
+
Wood
Photo: naturallywood.com
Photo: Nic Lehoux
Arena Stage: Mead Center for American Theater
District of Columbia
Architect: Bing Thom Architects

18. For decades, the wood industry has been evolving high-strength products in the form of engineered
wood—including plywood, oriented strand board, glulam beams, I-joists and laminated veneer lumber, to
name just a few examples. In addition to strength, engineered wood is also highly consistent and can be
manufactured to precise specifications. Adding to its sustainability advantages, it is often made from
(among other things) chips, particles, fibre's and wood from small-diameter trees not suitable for
lumber—which is part of the reason the wood industry now utilizes more than 99 percent of every
tree harvested and brought to a mill.
This photo shows the speed skating rink in the Richmond Olympic Oval, which was built for the
2010 Winter Olympic Games. It includes a 6-acre (2.4-hectare) free-spanning wood roof roughly
the size of four and a half football fields. For the Games, the Oval housed a speed skating track
with temporary capacity for about 8,000 guests. Afterwards, the facility was converted to multi-
purpose sports use.
Richmond Olympic Oval
British Columbia
Architect: Cannon Design
Limitless Structural Possibilities
Photo: naturallywood.com

19. One innovative engineered wood product is cross
laminated timber, or CLT, a material widely used in
Europe that is significantly increasing the possibilities
for North American wood buildings. CLT is comprised of
boards stacked together at right angles and glued over
their entire surface, creating a product that retains its
static strength and shape, and allows the transfer of
loads on all sides. Besides being dimensionally stable, it
is highly versatile, able to span long distances and
appropriate for use in all types of assemblies.
Internationally, CLT has propelled wood
construction to new heights, the most recent
example of which is the Forté, a 10-story
apartment building in Australia. It offers the
structural simplicity needed for cost-effective
projects, as well as benefits such as rapid
installation, reduced waste, energy efficiency and
exceptional design versatility.
In North America, CLT is relatively new but quickly
gaining momentum. In 2012, the American
National Standards Association approved
ANSI/APA PRG 320-2012 Standard for
Performance-Rated Cross-Laminated Timber, a
product standard that details manufacturing and
performance requirements for qualification and
quality assurance. Due to recently approved code
changes, CLT is scheduled to be included in the
2015 International Building Code. In the meantime,
a handful of innovative designers have already built
CLT structures in the U.S. and Canada, having had
them approved under the relevant code through an
alternative or innovative solutions path.
Photo: Lend Lease
Cross Laminated Timber
 Prefabricated, high-strength wood
solution that can substitute for
concrete, masonry and steel in
many applications
 Multiple layers, each oriented
crosswise to adjacent layers
 Versatile (floors, walls, roofs);
able to achieve long spans
 Can be prefinished
 Complements existing light and
heavy-frame options
Photo: Lend Lease
Forté – 10 stories
Australia
Developer: Lend Lease

20. The Crossroads, a 52,000-square-foot
client and staff reception area, is part of
the Promega Feynman Center, a 300,000-
square-foot Good Manufacturing Practices
(GMP) facility in Wisconsin. To contrast the
GMP with a warmer aesthetic while
meeting sustainability objectives, the
design team chose a combination of glued
laminated timber beams and a cross
laminated timber roof.
The structure has a complex footprint,
forming a sinuous S-curve that wraps
around one corner of the rectangular GMP
facility. The team was challenged to use a
material that would perform well for the
long-span deck needed to cover the
curved roof—and CLT provided the
solution. However, with virtually no square
angles in the structure, beam-to-column
connections were a challenge. To avoid
more than 100 different configurations, the
engineer designed a steel pin connector
that allows as much as 10 degrees rotation
in either direction, providing the required
swivel to fit nearly all of the connections.
Cross Laminated Timber
in the U.S.
Promega Feynman Center “The Crossroads”
Wisconsin
Architect and images: Uihlein-Wilson Architects, Inc.
View from Southwest

21. In Canada, British Columbia has been a leader in the development of CLT projects. One example is the
21,000-ft2 (2,000-m2) University of British Columbia Bioresearch & Demonstration Project in Vancouver,
which is designed to achieve LEED Gold certification. The first biomass-fueled heat-and-power generation
system of its kind in the world, the building will convert mountain pine beetle-killed wood pellets into
synthetic natural gas to offset 12 percent of the campus’ electricity. The facility was the first approved CLT
public building in Canada and incorporates 34,000-ft2 (3,100-m2) of CLT panels. Architecture firm
McFarland Marceau chose CLT as the structural material for several reasons. Most important, the size of
the equipment within the structure dictated installation prior to frame construction and a structural
material that could accommodate long spans without supports. Other keys to selection included wood’s
inherent environmental properties, particularly carbon sequestration, CLT’s ability to contain noise from
the biomass equipment, and speed of construction.
University of British Columbia Bioresearch
& Demonstration Project
British Columbia
Architect : McFarland Marceau Architects
Cross Laminated Timber
in Canada
Photo: naturallywood.comRendering: McFarland Marceau Architects

22. According to the National Fire Protection Association, property loss from fire was valued at
approximately $11.7 billion in 2011. While no building is completely fireproof, construction
materials and systems can improve a building’s fire safety.
• Concrete, and especially Insulating Concrete Form (ICF), is a good fire-resistant material.
Concrete can’t burn and, unlike steel, it won’t soften or bend. Concrete’s thermal mass
properties—slow absorption and release of heat—help to mitigate fire risk, and it is able to
achieve fire-resistance ratings without additional fireproofing.
• Structural steel requires fireproofing to prevent the steel from weakening in the event of a
fire. When heated, steel expands and softens, eventually losing its structural integrity and,
under extreme conditions, melting. According to the National Institute of Standards and
Technology, when exposed to fire, steel loses its strength and stiffness much faster than high-
strength concrete.
• Although seemingly counter-intuitive, wood can be an excellent performer under fire
conditions. According to the Southern Forest Products Association, wood outperforms non-
combustible materials in direct comparison fire tests. A 2x4 timber tie maintained more of its
original strength under higher temperatures and for a longer period than did aluminum alloy
or mild steel. This is because of wood’s unique charring properties. When wood burns, a layer
of char is created which helps to maintain the strength and structural integrity of the wood
beneath—a scenario that enables an exposed heavy timber system to achieve a fire-resistance
rating of up to 90 minutes. Properly designed wood-frame walls, floors and roofs using
conventional wood framing, wood trusses and wood I-joists can also provide fire resistance
ratings of up to two hours.
Sources:
Property loss estimate – http://www.nfpa.org/research/fire-statistics/the-us-fire-problem;
concrete facts – Concrete Alliance Inc.
http://www.theconcretealliance.com/CastinplaceReinforcedConcrete/tabid/56/Default.aspx;
wood performance fact – Southern Pine Use Guide, Southern Forest Products Association,
http:southernpine.com/pdf/200_Use_GuideL.pdf
Photo credit: FPInnovations – CLT tire testing
Fire Resistance
 Property losses from fire
were $11.7 billion in 2011.
 No building is completely
fire proof.
 Wood has outperformed
non-combustible materials
in direct comparison fire
tests.
Photo: FPInnovations
Advances in building science and fire
suppression systems have expanded
the scope and role for wood structural
and finish materials.

23. While seismic design is complex, there are certain general principles. To withstand earthquakes, buildings are designed to be flexible and move without breaking. This ability to
yield and deform without fracturing is called ductility.
According to Timber Engineering Europe, the type of construction that causes the most fatal injuries in earthquakes is unreinforced brick, stone or concrete buildings that tend
not to be flexible and to collapse when shaken. Metal can be formed to flex and bend without breaking, allowing the building to sway and reducing the stress on the building.
However, both the elastic limit and ultimate strength of wood are very high under short load durations, which makes it perform well in seismic events.
The many nailed joints in wood-frame structures make them inherently more ductile, which enables them to dissipate energy from the sudden shock of an earthquake.
Numerous load paths, such as those found in wood buildings, help avoid collapse in the event that some connections fail. Also, since forces in an earthquake are proportional to
the weight of a structure, wood’s relative light weight adds to its performance.
In California’s 1994 Northridge earthquake, where peak ground accelerations nearly broke records and were considerably higher than code requirements, many large structures
collapsed. At a hearing before the U.S. House of Representatives, a reason given for relatively limited death and damage toll was ... “The earthquake occurred at 4:31 a.m., when
the majority of people were sleeping in their wood-frame, single-family dwellings, generally considered to be the safest type of building in an earthquake.”
Source: The January 17, 1994 Northridge Earthquake, an EQE Summary Report, http://www.lafire.com/famous_fires/1994-
0117_NorthridgeEarthquake/quake/00_EQE_contents.htm
Seismic Performance
 Low mass and high flexibility make wood-frame buildings more
resistant to earthquake damage than concrete or steel-frame
buildings.
 High strength-to-weight ratio makes wood a good structural material
in terms of seismic performance.
Three undamaged wood-
frame buildings
(background) next to an
older building (foreground)
whose ground floor has
collapsed completely;
Nishinomiya, Japan,
Hyogo-ken Nanbu
Earthquake, 1995.
Photo courtesy European Wood China

24. This photo is from a ‘shake table’ test
conducted in Japan, during which a full-size
prototype of a six-story wood-frame building
withstood forces greater than those of the
1995 Kobe earthquake. The structure suffered
no visible damage.
Click on image to go to video of the shake
table test (note – on YouTube).
Shake Table Test – Six
Story Wood Building
In 2009, a full size prototype of
a six-story wood-frame building
successfully passed a seismic
‘shake table’ test conducted in
front of 400 international
observers in Japan. Subjected
to seismic forces greater than
those of the 1995 Kobe
earthquake, the structure
suffered no visible damage.
Photo: John van de Lindt, University of Alabama

25. MATERIALS IN THE CONSTRUCTION PHASE
SECTION 2

26. This section of the presentation will consider
materials during the construction phase,
including the trend toward prefabrication and
panelization, and advantages of wood use such
as adaptability and light carbon footprint.
The project in this slide is The Quarter,
which includes three separate four-story
wood buildings. Two of the structures rest
on a 50,000-square-foot post-tensioned
concrete podium deck, which separates
ground level parking from 150 high-end
residential apartment units.
The Quarter
Maryland
Architect: Poole & Poole Architecture
Materials in the Construction Phase
Photo: Davis & Church, LLC

27. Panelizing, the process of assembling roof or wall sections on the ground and then
lifting them into place, allows contractors to reduce labor and material costs while
offering faster construction.
Panelized wood roofs are a particularly good choice for low-slope roof structures
such as big box stores and warehouses. There are two basic types of panelized wood
roof systems:
• All-wood systems consisting of glulam beam girders with wood purlins, wood sub-
purlins and a wood structural panel deck, are commonly seen in buildings with spans
of less than 40 feet. They’re particularly well suited for applications where conveyor
equipment is hung from the roof structure or in food-processing facilities that need
to minimize dust from overhead joists. This is also a good choice for designers who
want to take advantage of wood’s aesthetic benefits for an exposed roof structure,
for example in retail or school applications.
• Hybrid systems consist of steel purlin and girder trusses together with wood sub-
purlins and a wood structural panel deck. The long span capability of steel framing
makes this system particularly economical when spans are more than 32 feet. Wood
decking allows better economy than steel, both in terms of material and installation
costs. This is usually the system of choice for large warehouse and industrial
structures requiring long spans.
CLT is another panelized system that is increasing the opportunities for wood design.
Trends
 Prefabrication
and penalization:
 Pre-cast concrete
 Pre-fabricated
steel
 Panelized wood
products
Hybrid steel/wood panelized roof

28. Wood’s advantages on the job site include
adaptability—which allows contractors to
make modifications during construction, even
to a building’s floor plan, the number of
rooms, interior design or overall appearance.
This same adaptability means wood structures
are well suited to renovations if the needs of
the occupants change.
Timber’s thermal efficiency also means walls
can be slimmer, creating more usable floor
space.
For those who want to verify that the products
they use come from sustainable sources, wood
is also the only material that can be purchased
with chain of custody documentation that
provides product tracking throughout the
entire supply chain from harvesting, processing
and transportation to the end consumer.
 Adaptability, allows
modifications during
construction and later
renovations
 Thermal efficiency,
maximizes useable floor
area
 Product stewardship:
Chain of Custody
certification
Photo: Arch Wood Protection
Wood’s Advantages On-Site

29. Another pressing issue during construction concerns the environmental
impacts of getting materials to the job site. This slide shows the results of a
study examining the carbon footprint implications of transporting four wood
products from British Columbia, Canada to the UK—namely softwood
lumber, softwood plywood, western red cedar lumber and western red cedar
siding.
The study—which was undertaken in accordance with a strict UK protocol
known as PAS 2050—took into account the greenhouse gases emitted during
the harvest, manufacture and transport of the products. It also considered
the fact that wood products continue to store carbon absorbed during the
tree’s growing cycle, keeping it out of the atmosphere indefinitely.
The results showed that, despite being transported more than 16,000 km
(9,900 mi), all four wood products in the study represent a net carbon sink
upon delivery ... that is, each product stores more carbon than is emitted
during its respective harvest, manufacture and transport. Unlike wood, steel
has no such carbon storage capacity to offset the environmental costs of
transportation.
Carbon Footprint Study
 UK was first to have a
Publicly Available
Specification—PAS
2050 —for assessing
the carbon footprint of
individual products
 Study assessed four
BC wood products
marketed in the UK
Source: A Carbon Footprint of Four Canadian
Wood Products Delivered to the UK as per PAS
2050 Methodology, prepared by the Athena
Institute and FPInnovations, 2010,
www.naturallywood.com
Despite being transported more than 16,000 km
(9,000 mi), all four Canadian products represent a
net carbon sink upon delivery in the UK.
Results shown are per cubic meter (m3) of product

30. MATERIALS IN THE USE PHASE
SECTION 3

31. This section of the presentation will focus on
the environmental impacts associated with
materials in the use phase.
The building in the photo is the basketball
arena of the 320,000-square-foot El Dorado
High School. Glulam bowstring roof trusses
span 160 ft over the basketball arena.
Designers used exposed wood and natural
light to create an environment that would
motivate students to stay in school.
Eldorado High School
Arkansas
Architect: CADM Architecture
Materials in the Use Phase
Photo: Dennis Ivy, courtesy WoodWorks

32. According to the U.S. Department of Energy, buildings account for 38 percent of total U.S. energy
consumption. However, there are certain terms that should be understood as it relates to energy.
There are two forms of embodied energy in buildings: initial embodied energy and recurring embodied
energy. For building materials, initial embodied energy is the non-renewable energy consumed in raw
material acquisition, processing, manufacturing, transportation to site, and construction.
Recurring embodied energy is the non-renewable energy consumed to maintain, repair, restore, refurbish
or replace materials, components or systems during the life of the building. It’s related to the durability of
the building materials, the building’s components and systems, how well these are maintained, and the
life of the building.
Operating energy refers to the energy buildings consume for heating, cooling, ventilation, lighting,
equipment and appliances. Increased insulation in foundations, walls, doors, and windows may improve
the operating efficiency of a structure, but the insulation products themselves may increase the
structure’s embodied energy. Appreciating—and balancing—the need to reduce operating energy in
buildings and its effect on embodied energy is critical to true sustainability.
Terms and Definitions
 Initial Embodied Energy
 Non-renewable energy consumed in raw
material acquisition, processing,
manufacturing, transportation and installation
 “Cradle to Gate”
 Recurring Embodied Energy
 Non-renewable energy used to maintain,
repair, restore, refurbish or replace materials
and components during a building’s service life
 Related to building durability
 Operating Energy
 Energy consumed by buildings to maintain the
internal environment and ensure system
functionality
Trade-offs and
synergies

33. Energy performance of buildings depends more on insulation, air sealing and other factors
than the choice of structural material. All buildings are typically insulated well, so they tend to
have essentially comparable energy performance. The embodied energy of a building,
however, is very much affected by structural material. This chart is based on life cycle
assessment (LCA) calculations for identical 2,400-square-foot homes designed according to
standard local practice. The wood house had less embodied energy than the concrete or steel-
framed structures. Concrete structures had the highest embodied energy.
According to the NAHB Research Center, insulated concrete forms (ICF), rigid plastic foam
forms that hold concrete during curing and remain afterwards to serve as thermal insulation
for concrete walls, are superior insulators to standard concrete. But materials with a heavy
carbon footprint like concrete can skew the balance between embodied and operating
energy.
About the graphic:
• Data comes from an LCA study of different house framing, by the Athena Sustainable
Materials Institute for the Canadian Wood Council in 2004. The graphic shown here was
generated from the dataset but was not reported in the original study.
• The LCA calculation was done by Athena using its software and databases.
• The operating energy was calculated by Morrison Hershfield engineers, using Natural
Resources Canada’s HOT2000 software, and using a Toronto climate. A 60-year period was
used.
• The homes are identical 2400-square foot typical homes designed according to standard
local practice. The concrete house features insulated concrete forms.
Embodied Plus Operating
Energy Over 60 Years
Sources: Athena Sustainable Materials Institute, Canadian Wood Council, Morrison Hershfield Engineers, 2004

34. As this graphic illustrates, a typical concrete house has
nearly as much energy embodied in the materials as it takes
to run the house for 20 years. If the embodied energy is
increased by adding much more insulation, it is important to
make sure that the savings in heating energy will be greater
than the embodied energy in the insulation.
This is from the same research as the previous slide.
Reducing Operating and
Embodied Energy
Sources: Athena Sustainable Materials Institute, Canadian Wood Council, Morrison Hershfield Engineers, 2004

35. The thermal conductivity of building materials has direct bearing on their performance as insulators. Low thermal conductivity indicates that a
material is a poor conductor of heat and therefore a good insulator. Any material with open pockets of air will insulate better than a material
that’s solid. Wood is made up of thousands of tiny open cells that limit its ability to conduct heat. The thermal properties of wood are 400
times better than steel and 10 times better than concrete.1 Their higher conductivity means steel and concrete must overcome lower R-values
associated with thermal bridging; as a result, they require more insulation to provide the same level of energy efficiency.
This graph illustrates energy performance in two similar houses near Chicago. The steel house has significantly more insulation than the wood
house and still can’t perform as well. In addition, the steel house has a lot more embodied energy, which is not reflected inthe graph.
The two identical houses, unoccupied but with heating and cooling systems operating, were built to standard practice for wood-frame and
steel-frame. Data was measured for one year and also simulated with software in order to normalize and validate results. Both houses have
fiberglass insulation between the studs. The steel house has more insulation volume, because its studs are spaced at 24 inches vs. 16 inches
for the wood house. In addition, the steel house has a 3/4-inch layer of rigid polystyrene board mounted to the outside of the framing
sheathing—standard practice for steel framing—to reduce conduction of heat at the studs. Yet even with these benefits, the steel house still
cannot perform as well as the wood house. Steel framing requires a layer of exterior polystyrene foam, which adds cost and embodied
environmental effects. If the wood studs were spaced at 24 inches, like the steel (which is sometimes the case), the wood performance would
be even better.
Source: The homes were the subject of a 2002 study prepared for the U.S. Department of Housing and Urban Development, the
North American Steel Framing Alliance and the National Association of Home Builders by the NAHB Research Center.
http://www.huduser.org/portal/publications/destech/steelval.html
1Thermal Performance of Light-Frame Assemblies, Canadian Wood Council,
http://cwc.ca/documents/IBS/IBS5_Thermal_SMC_v2.pdf
Thermal Performance:
Wood vs. Steel Homes
Sources: NAHB Research Center for US Department of Housing and Urban Development, the North American Steel Framing
Alliance and National Association of Home Builders, 2002.

36. END OF USE – A CLOSER LOOK AT
RECYCLING AND REUSE
SECTION 4

37. We’ve already talked about the
importance of considering a material’s
environmental impacts during
construction as well as a building’s
operational phase, but what about it’s
end-of-life impacts?
The U.S. EPA estimates that the U.S.
generated more than 160 million tons of
building-related construction and
demolition (C&D) waste materials in
2003—nearly 53 percent of which was the
result of demolition activities, 38 percent
from renovations, and nine percent from
new construction. Only 40 percent of this
waste was estimated to be reused,
recycled or sent to waste-to-energy
facilities, leaving 60 percent going to
landfills.
Source: US Environmental Protection
Agency,
http://www.epa.gov/wastes/conserve/i
mr/cdm/index.htm
The U.S. generates more than
160 million tons of construction
waste per year.
Only 40% is estimated to be
reused, recycled or sent to
waste-to-energy facilities,
leaving 60% going to landfills.
Source: U.S. EPA, 2003
End of Life: Reduce,
Reuse, Recycle
Photo: courtesy Metro Vancouver

38. In the context of reducing end-of-life impacts, it’s important to highlight the need to
minimize waste from the outset by making the most of our resources.
The forest industry is organized to maximize resource efficiency and derived value by
making the most out of every tree harvested. For example, high value saw logs are
utilized for lumber, while lower value logs are used for pulp, and residual biomass
and byproducts from pulping are used for bio-energy, bio-chemicals and bio-
materials.
The industry also has a number of interconnected sub-sectors that collectively
maximize resource efficiency and derived value. It’s common for companies to have
cogeneration facilities, also known as combined heat and power, which convert
sawdust, bark and other residual fiber to electrical and thermal energy.
In this way, the North American wood industry now utilizes nearly 99 percent of
every tree harvested and brought to a mill.
Source: The Current State of Wood Reuse and Recycling in North America,
Dovetail Partners Inc.,
http://www.dovetailinc.org/reportsview/2013/responsible-materials/pjeff-
howep/current-state-wood-reuse-and-recycling-north-amer
Reduce: Minimizing Waste
from the Outset
 Zero waste –harvested trees are almost entirely converted into usable
product.
 Plywood is a panel product made from wood fiber unsuitable for
lumber.
Photo: naturallywood.com

39. Reusing wood also has obvious benefits when you consider the impacts of waste disposal, but it also has an impact on their carbon footprint.
As discussed earlier, wood products store carbon absorbed by trees during their growing cycle. Reusing wood extends the amount of time the
carbon is stored—keeping it out of the atmosphere even longer.
Salvaged wood is valued for its beauty and requires very little energy to process, so the impacts are largely related to transportation. But its
use is not without obstacles, since some areas have more established salvaged wood markets than others.
The photos on this slide illustrate two interesting examples of wood’s reuse potential.
Through a novel collaboration between the client and the city, the team developing the Greater Texas Foundation building on the
left—led by Dunnam Tita Architecture + Interiors—was able to salvage a large quantity of antique long-leaf pine from the structure
of a recently demolished warehouse. This “very local” reclaimed material is prominently featured throughout the new building, in
applications that range from structural blocking inside walls to finished wood floors, exposed roof decking, wood ceilings, the front
door and several custom furniture pieces.
The Freight & Salvage Coffeehouse, designed by Marcy Wong Donn Logan Architects, exemplifies the use of wood where
acoustics, reclaiming history and ideals all come together. Much of the new building’s structural system (in the form of salvaged
wood trusses) and all of the paneling in the theater (re-milled roof decking) came from the site’s previous building. The weathered
wood used in the theater auditorium—combined with state-of-the-art acoustic backing—created a striking, vintage feel that would
have been difficult to recreate with another material. It also helped the design team meet its sustainability objectives.
Photos: (left) Casey Dunn, courtesy of Dunnam Tita Architecture + Interiors; (right) Sharon Risedorph Photography, courtesy of
Marcy Wong Donn Logan Architects, Inc.
Wood ‘’Waste’’ is Valuable
Freight & Salvage Coffeehouse
California
Architect: Marcy Wong Donn Logan Architects
Photo: Casey Dunn Photo: Sharon Risedorph
Greater Texas Foundation
Texas
Architect: Dunnam Tita Architecture + Interiors

40. As part of the green building movement,
there’s a trend toward designing buildings for
deconstruction, which requires less use of
resources—in other words, design to facilitate
salvaging components during demolition for
reuse in their original high value format. Most
green building rating systems award points for
the use of salvaged materials.
The Lynn Creek branch of the Vancity bank
shown in the photo used wood salvaged from
a railway trestle in Quesnel, British Columbia.
The bridge was disassembled and the wood
then graded for structural use.
Design for Reuse
 This heavy timber
structure was sourced
from a railway trestle
bridge in Quesnel, B.C.
 The bridge was
disassembled and the
wood then graded for
structural use.
Vancity Lynn Creek Branch
British Columbia
Architect: Toby Russell Buckwell Partnership
Photo: Green Building Brain

41. The concrete and steel industries have made great strides in recycling their materials. Recycled concrete
aggregate has found ready markets as road base, asphalt pavement, soil stabilization, pipe bedding and
landscape materials; occasionally it is used as aggregate for new concrete. Steel is widely recycled as well. In a
year, the American Iron and Steel Institute says the North American steel industry saves the equivalent energy,
from recycling alone, to power about 18 million households for a year.
However, while recycling extends the life of our resources, a closer look is warranted. Although reusing
concrete aggregate is referred to as recycling, some maintain it’s actually down-cycling, as the greatest
economic value is in the cement, which can’t be reused. “Design for Deconstruction,” a report prepared for
California’s Chartwell School partially funded by the EPA, says, “Crushed aggregate even tends to require higher
cement mix designs, offsetting some of the benefit and reducing virgin aggregate use.” While recycling saves
energy, it also expends energy and sometimes in large amounts, particularly in the case of steel. The Chartwell
School study says that recycling steel takes 50 percent of the energy required to refine steel from ore.
Sources:
Steel fact – American Iron and Steel Institue,
http://www.steel.org/~/media/Files/AISI/Fact%20Sheets/50_Fun_Facts_About_Steel.ashx
Chartwell study – Design for Deconstruction, http://www.lifecyclebuilding.org/files/DFD.pdf
Revisiting Recycling
 Difference between recycling and down-cycling
 Material value should not be depleted in the recycling process.
 Recycling metals requires large amounts of fossil fuel energy.
Steel mill with two electric arc furnaces.
Recycling scrap steel requires about 50% of the
energy need to smelt virgin steel from iron ore.
Photo: wikipedia

42. In some instances, a material with no recycled content can actually be a more
sustainable choice than a recycled material. This chart shows the results of a life
cycle assessment comparing the environmental profile of two standard
structural post-and-beam systems, one with wood and one with steel, and a
third option using a theoretical steel with 100 percent recycled content. The
wood system is glulam beams on wood columns with no recycled content. The
steel system is standard wide flange beam on hollow structural section columns;
recycled content is 25 percent, typical for the industry. The wood performance is
set as the benchmark at 100 percent, and the other sets of bars are shown by
percentage better or worse than the wood.
Figures were calculated by FPInnovations using the ATHENA Impact Estimator for
Buildings.
A Closer Look at Recycled Content
Source: FPInnovations, calculated using the Athena Impact Estimator for Buildings, 2008

43. EVOLVING BUILDING CODES
SECTION 5

44. options for wood use in construction. Earlier in this article, reference was made to the fact that CLT will be included in the 2015
IBC. This particular code change is getting a lot of attention because of the ground breaking nature of CLT; nine- and ten-story
CLT buildings exist and exciting concepts have been developed for going higher still. However, the possibilities for wood use
have actually been expanding since the IBC was introduced in 2000.
The IBC consolidated three regional model building codes into one uniform code that has since been adopted by most
jurisdictions. It created more opportunities for wood use by (among other things) recognizing additional fire protection techniques,
and combining the maximum allowable heights and areas from the three legacy codes into one (thus increasing what's allowable
in some jurisdictions).
So – how high can a building be under the IBC?
IBC – Expanding
Opportunities for Wood
 Recognized
additional fire
protection
techniques
 Combined three
model codes,
thus increasing
maximum
allowable
heights and
areas in some
jurisdictions
Photo: Matt Todd courtesy WoodWorks
Marselle Condominium
Washington
Architect: PB Architects

45. Most midrise wood buildings are Type V Construction and four stories or less. However, Type
III offers far greater opportunities for achieving high density at a relatively low cost ... while of
course meeting all requirements for safety and performance.
Like all construction types, Type III has base limitations with regard to height, number of stories
and square footage. However, the IBC allows increases to these tabular amounts per other
code sections.
Source for slides 38-42: Tim Smith, Architect, Togawa Smith Martin, presentation at the 2013 American
Institute of Architects Conference
Base Code Height
1989 – UBC
Base code height – Table 5B
Type IIIA / 2009 – IBC
Base code height – Table 503

46. For example, when a building has an NFPA 13-compliant automatic sprinkler system, the
floor area can be increased by 300% for a one-story building and 200% for a multi-story
building. In addition to the area increase, IBC Section 504.2 allows a 20-foot increase to the
tabular building height and an additional story above the grade plane. The exception to his
is Group I-2 occupancies, which include hospitals and nursing homes and are not allowed
the extra story.
Adding an automatic sprinkler system not only means that a five-story wood building is
allowed, it means a maximum height of 85 feet instead of 65 feet. So how do we maximize
the vertical envelope to take advantage of the extra height when a typical five-story building
is only about 55 fee
Sprinkler System
1989 – UBC
Sprinkler increase – Section 506
Type IIIA / 2009 – IBC
Sprinkler increase – Section 504
Add 1 floor
Increase height 20 feet

47. First we add another level. Under the 2009 IBC, you can
add a wood-frame mezzanine on top of a multi-story
wood building. The area of the mezzanine can’t be more
than 1/3 of the floor below and isn’t defined as a ‘floor’ or
‘story.’
Starting with the base height and then adding a sprinkler
system and now a mezzanine gets us to six levels of
wood-frame construction and about 65 feet in height.
Mezzanine
1989 – UBC
1989 – UBC
Mezzanine – Section 507
Type IIIA / 2009 – IBC
Mezzanine – Section 505
Add level 1/3 of floor below
& not defined as a floor

48. Podium
1989 – UBC
Podium – Section 311.2.2.1
2009 – IBC
Type IIIA / 2009 – IBC
Type I Podium – Section 509.2
Separate buildings for area and stories
3-hour separation between Type I and III

49. … We use a sloping site to our advantage.
The IBC recognizes that the world isn’t flat. It allows semi-basements
or daylight basements providing they don’t extend from grade more
than 12 feet at any one point and don’t extend more than 6 feet from
the average grade. As with mezzanines, this ‘basement’ level is not
considered a ‘floor’ or ‘story’ … but it gives us an eight-level building
that’s in the range of 85 feet high.
Using a combination of Type III and Type I, we’ve now maximized the
vertical envelope.
Semi - Basement
1989 – UBC
Height definition – Section 208
Type IIIA / 2009 – IBC
Grade plane definition – Section 502
Add another level with
daylight basement

50. In the U.S., it is becoming increasingly
common for designers to include five
stories of wood over a concrete podium.
Here’s another image of the Marselle,
along with two other five-story
buildings—Americana at Brand and the
University of Washington West Campus
Student Housing Project, Phase One.
Podium Buildings
Marselle Condominium
5 ½ stories of wood
Washington
Architect: PB Architects
Photo: Matt Todd
Photo: Togawa Smith Martin
Photo: Benjamin Benschneider
University of Washington
5 stories of wood
Washington
Architect: Mahlum
Americana at Brand
5 stories of wood
California
Architect: Togawa Smith Martin

51. The trend toward taller wood buildings
is also apparent in Canada. In 2009, for
example, British Columbia increased
the allowable height of residential
wood buildings from four stories to six.
Library Square, shown here, was one of
the first buildings built under the new
code. It includes five stories of wood
over one story of concrete.
Six Stories in British Columbia
 Effective starting
April 2009
 Concrete-wood
hybrids also allowed
(maximum height
60 ft)
Photo: naturallywood.com
Library Square
6 stories
British Columbia
Architect: JM Architects

52. As this presentation has shown, wood
offers significant advantages during
construction, operation and end-of-life,
and reaffirms that in the quest for
carbon-neutral buildings, materials
matter.
The building in this photo is the
Kwantlen University College Trades &
Technology Centre. Large glulam beams
are featured predominantly, and locally
produced materials were used
throughout the project. The beams
were produced within a 500 mile radius
of the campus.
 From harvest to end-of-life,
wood proves its value as a
sustainable building material.
 Unique features of wood:
 Strong and durable, performs
effectively in fires and earthquakes
 Less embodied energy than steel
or concrete, and is a natural
insulator
 Has a light carbon footprint
 Lends itself to recycling and reuse
without significant energy input
Photo: naturallywood.com
Kwantlen University College
British Columbia
Architect: Bunting Coady Architects
Materials in Action Matter

53. For more information on building with wood, visit
rethinkwood.com
THANK YOU!