2. Materials and finishes
Rigorous planning makes it possible to use materials and finishes that have a lesser impact on the environment, especially in terms of carbon emissions.
It is important to take into account the entire life cycle of materials. The Athena Institute (http://www.athenasmi.org/about/lcaModel.html) offers a good model for this approach.
Built by students at the University of California, the Green Design Wiki offers good information and examples of materials and finish choices:
Wood offers many environmental advantages:
- Lower environmental footprint than other building materials such as steel or concrete, in terms of embodied energy, air and water pollution, and greenhouse gas emissions
- Better insulating value than steel or concrete, which reduces the need for heating and cooling
- Recyclable and biodegradable: it is the only major building material that is renewable and carbon-neutral
- Structurally sound: in adverse natural conditions such earthquakes and high winds, wood structures are proven to be among the safest building systems
When using wood, it is recommended to seek a certified wood product, without formaldehyde or with a minimal or null degassing, and requiring a minimum of transport during its life cycle. Both the Canadian Wood Council (http://www.cwc.ca/) and the Centre for Expertise in Commercial Wood Construction (French only: http://www.cecobois. com/) offer good information.
Engineered wood products include glulam (glued-laminated timber), parallel strand lumber (PSL), laminated veneer lumber (LVL), plywood, and oriented strandboard (OSB), waferboard, prefabricated wood trusses and wood joists.
Engineered wood products usually are considered sustainable. Entire trees, regardless of species, shape, and age can be used to make engineered wood products.
Some wood products, for example, make use of smaller trees, species not commonly used for lumber, or use chips and particles generated as by-products from other production processes. A key advantage of engineered wood products is that they are very stable and offer greater structural strength than typical wood building materials. This means that wood joists and beams can be used instead of steel ones in many building projects. Increasingly, builders are using engineered wood products for joists, beams, studs, window and door frames.
Specialty engineered wood products offer unique characteristics suitable for building diverse end-use products such as boats, truck bodies and even upholstered furniture. Engineered wood products can be designed and ordered to specification, thereby reducing construction waste. This helps to balance demand for the larger trees and more desirable wood species.
For example, buildings meeting the requirements of Canada’s C-2000 program can use structural members of engineered wood products that can potentially reduce construction waste by up to 75%.
Rapid regrowth wood
There are different products made from rapid regrowth wood species such as laminated strand lumber (LSL), manufactured from indigenous Canadian wood with fast rejuvenation which were not traditionally used commercially. There are also several products made from rapid regrowth tropical wood, such Durapalm (http://www.durapalm. com) and Plyboo (http://www.plyboo.com).
Perdure, or high temperature wood treatment, is an ecological substitute for chemically treated wood, which extends the service life of wood and can applied to all species. The wood is treated at a high temperature without chemicals, sterilizing the wood and offering protection against insects and micro-organisms. With several advantages on the environmental view, wood products issued from Perdure technology use less expensive species, allowing production of less expensive exotic wood substitutes. Environment Canada offers good information on this technology:
Lauan is a veneer wood. See the following sites for more information:
Medium-density fibreboard (http://en.wikipedia.org/wiki/Medium-density_fibreboard) is an engineered wood which has multiple advantages:
- Almost isotropic, that is it shows homogeneous physical properties in the three dimensions
- Its fine texture is attractive
- Cheaper than solid wood
- Available in various thicknesses
- Uses first thinning wood (small diameter trees that can’t be used as solid wood)
- Can be flame resistant, arched, lacquered or melamine-faced (UB)
- Can be to a certain extent waterproof (for indoor use and temporary exposure to humidity)
Cardboard is also often used in exhibit design since it has the same durability as wood. It is generally made from recycled materials, and its malleability allows for the reproduction of ancient furniture and ancient objects that do not have the conventional geometrical forms we see nowadays.
Note that these objects and furniture are usually light, affordable and can be protected with “green” coating such as silk paper and recycled water-based paint. Vitrification treatment can also make them water and stain repellent.
C. Green fabrics
The raw materials of green fabrics come from plants or animals. The manufacturing process respects well-defined specifications and minimizes environmental risk.
D. Formaldehyde-free materials
According to both Health Canada and Environment Canada, low-molecular weight aldehydes, such as formaldehyde, are highly flammable reactive compounds. At room temperature formaldehyde is a reactive gas.
Various exhibition materials can be sources of gas emissions, such as pressed wood panels or any other product made with adhesives that contain formaldehyde, as well as varnishes, paints, carpets, dyes and curtains.
Public Works and Government Services offers a good publication The Environmentally Responsible Construction and Renovation Handbook:
E. Low or no-VOC adhesives
Use low-toxic or water-based adhesives for carpeting. Conventional glues are very high in VOCs and off-gas for long periods of time. Choose water-based glues or natural, plant-based glues. Pure silicone is efficient with windows and bathrooms: when dry, the silicone becomes non-toxic. Latex or other water-based sealers can be used anywhere indoors. Be careful with bathroom and kitchen sealers as some contain fungicides which trigger allergies in some people.
F. Low or no-VOC paints, stains and sealants
When designing an exhibit, choosing your paints, stains, and sealants is an important part of the sustainable development approach. VOCs are made of carbon and hydrogen that can turn into gas in the air. Paints often contain VOCs. Oil and latex-based paints contain toxic chemicals that cannot be subsequently processed. These organic chemicals, such as cyanide, evaporate easily into the atmosphere, and contribute to global warming. Instead of traditional paints, look for no-VOC paints, made with talc powder, clay or chalk, as they have a lesser environmental impact.
G. Recycled plastics and glass
Not only does recycling reduce waste volume, and in turn any resulting pollution (some materials take decades, if not centuries, to break down); it also saves natural resources as it reduces the need to extract new raw materials.
Lexan (http://en.wikipedia.org/wiki/Lexan) is a good alternative to Plexiglas as it is highly durable, malleable and resistant to sunlight.
H. Plastics with a natural compound base
Bioplastics (http://www.greendesignwiki.com/index.php?title=Bio-based_ plastics_%28alternatives_to_acrylic%29) are a form of plastics derived from vegetable oils, wood fibres and starches. They contain no petroleum and have less impact on the environment.
I. Carpets and floor coverings
When choosing your floor covering, you need to consider not only the product materials themselves, but also the sustainability of those materials, the products that will be used for their maintenance and whether the product is recyclable at the end of its life cycle. Many so-called sustainable floor coverings emit high levels of VOCs and cannot be recycled nor reused. There are many alternatives, such as flooring made of bamboo or cork, modular carpeting, concrete, linoleum and other coverings made from recycled and recyclable materials.