ECO and GREEN

Wood for good. Way Wood?

Aesthetic appeal

The beauty of wood is that it engages all of our senses. Warm, rich and affecting, its surface has a tactile and sensuous strength, while the range of timber hues and the depth of individual grain delights the eye. Its appeal in design and construction is a natural one, as of course, all of these sensual elements are present when we build with wood. Wooden structures effortlessly combine aesthetics and strength, thermal protection and environmental benefits to create spaces of optimal look, feel and function. The unique properties of wood is the reason of the continually increased demand in residential, public and commercial buildings. Timber is one of the world’s top performing construction materials. Tried and tested over centuries, it’s inherent beauty, strength and durability has seen it remain one of the most popular building materials to this day. Developments and advancements in engineered wood products and in timber treatments mean that timber can now be used where once materials like steel or concrete were the only option. And in key areas of acoustics, thermal performance, strength and fire resistance – timber is not just capable of answering a wide range of specifications but also of performing strongly, each and every time.

Acoustic performance

Not only aesthetically pleasing, timber also provides excellent acoustic properties, with many high-end architectural projects featuring internal timber applications. Timber performs strongly in the acoustic arena - whether the objective is to enhance sound or reduce sound. Its network of small interlocking wood cells converts sound energy into heat energy by frictional resistance within these cells and by vibrations within their sub-structure.

Because of this internal friction, wood has a stronger sound dampening capacity than most structural materials. While a concrete wall will also reflect sound, it does so in a much harsher way, resulting in stronger echoes. The natural acoustic properties of timber control this excessive echo, or reverberation, by reducing the transmission of sound vibrations. These properties of timber are why many public buildings, clad walls and ceilings are lined with acoustic timber panels or spaced timber battens.

Fire performance

While timber is indeed a combustible material, in construction it has significant insulating properties and burns in a slow, predictable and measurable way. These factors see timber perform strongly against fire and give designers the ability to confidently create strong, durable, fire resistant timber constructions. When exposed to the heat of a fire, timber goes through a process of thermal breakdown into combustible gases. During this process, a layer of charcoal forms on the burning surface of the timber and it is this charred layer that is the key contributing factor in timber's fire resistance. The layer acts as an insulator protecting the inner core of the timber, making it resist heat penetration and thus burn more slowly; while the temperature of the inner, uncharred core remains low, enabling it to continue to carry its load. Initially the rate of charring is fast but as the char depth increases it provides a stronger protective layer to the timber, slowing the overall combustion rate. The self protecting nature of the charring layer increases the likelihood of a timber structure surviving fire as the uncharred inner core remains unaffected, maintaining its strength and with it the structure's stability.

Strength performance

As the knowledge and understanding of different timber species has grown, so too has the use of timber in applications where strength is a key performance criteria. Timber's superior strength qualities provide a versatile and reliable building material for a wide range of structural applications - from beams, walls and flooring through to formwork and large timber panels. Backed by Australian Standards for design and construction, timber framed construction is tough and reliable. When combined with good design and detailing, it can withstand some of the most extreme weather conditions Australia has to offer. Structurally graded solid timber, is a popular choice for framing material in Australia. Sawn timber, particularly in seasoned form, is highly valued in structural applications for its favourable strength-to-weight ratio, durability and dimensional stability. When used in large engineering construction, its strength performance is based on visual grading and the durability rating of the species. For domestic construction, mechanical grading is also utilised.

Density is the single biggest factor influencing the strength of a piece of timber and while solid timber hardwoods are indeed dense, timber density can be increased even further through the creation of engineered wood products. One of the latest engineered wood products on the market is CLT or cross-laminated timber. CLT has been described as 'giant plywood' and is made in much the same way - but on a larger scale. Large CLT panels offer the same strength as a concrete equivalent but are significantly lighter, creating obvious benefits. While there is a plethora of buildings, both residential and commercial, that have been constructed out of pre-fabricated concrete panels, the reality is that CLT panels can now do the same job, even more efficiently.

Thermal performance

When considering thermal performance issues, timber, a naturally insulating material, makes for an excellent choice. Air pockets within timber's cellular structure create a natural barrier to heat and cold.

Of all the timber options in construction, lightweight timber is the best insulator overall as thermal conductivity increases with density. Construction design with a focus on energy efficiency through lightweight timber can greatly contribute to maximising comfort and minimising non renewable energy use. In addition, timber framed buildings can allow for extra insulation materials to be placed in spaces between framing members without increasing wall, ceiling, roof or floor thickness. The natural thermal properties of timber also maximise the efficiency of insulation materials as wood will not become cold or dissipate heat, therefore requiring less energy to maintain warmth throughout a building.

Recycling and wood waste

It is increasingly common practice to recycle and reuse what would otherwise be timber residue into new products and applications. The versatility of timber is no better demonstrated than in the variety of second life products it makes its way into. Particleboard manufacture is increasingly utilising recycled wood packaging and off cuts in the production of new particleboards. Animal bedding, mulch and composts continue to make excellent use of the natural moisture retaining properties of timber and more and more timber salvaged in the demolition of large buildings is finding new life as features in contemporary designer buildings. The environmental benefits of such reuse are obvious - not only is the service life of the timber extended (and with it the need for a new product eliminated) but in addition, the carbon contained within the recycled timber is stored for the life of the new product. When wood residue from timber processing cannot be recycled it can still be used to produce biomass energy. Biomass energy is a renewable energy, sourced from natural materials like wood, which is then generated into heat or electricity. Wood residue used in energy production provides two fold environmental benefits. Firstly, its use reduces industry reliance on environmentally damaging fossil fuels, in turn preventing the release of long-term carbon store from sources that cannot be replenished. Secondly, the energy itself omits far fewer greenhouse gas emissions than typical alternatives.

Manufacturing efficiency and flexibility

Timber is strong, lightweight and flexible, making timber construction simple and safer than common alternatives. Choosing timber means there isn't the need to contend with heavy lifting and large cranes to secure materials onsite, making building sites safer work places. In addition, when working with timber, the range of timber products can be shaped and machined onsite, offering a significant benefit for project management and turnaround times. Advances in modern technology enable fast and accurate installation of engineered wood products like LVL members. Specialist manufacturers use high tech prefabrication that guarantees accuracy and ensures rapid construction. Pre-fabricated LVL building systems can be used for multi-storey commercial and long span industrial portal framed buildings. In contrast many alternate construction materials like steel must be fabricated and finished in a factory and then bought to the site for assembly. In most cases onsite welding and grinding is required, thus creating additional site safety issues to contend with, like fire danger. Whereas LVL can usually be assembled with standard fittings such as nails and bolts, steel will require a specialist contractor onsite, adding costs and time to any project. In short timber offers an efficiency and flexibility that common alternatives like steel just can't match. Materials like steel will generally require more equipment, more contractors and offsite fabrication and finishing, which ultimately equal increased labour costs and time.

More about "Way wood?"

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Eco-friendly materials

In general, one could say that insulation is environmentally friendly when it is made from natural materials. The most commonly used materials are: cotton cellulose (paper from recycled newspaper), hemp, wood fiber or straw. They are generally used in the form of panels or rolls. However cotton cellulose can be applied by spraying or insufflating into the walls. These materials have a performance comparable to synthetic materials that are commonly used in construction. However their implementation requires real skills, especially for straw or insufflation of cellulose.

Energy independency trough
the latest building technologies

The construction industry is a large contributor to CO2 emissions, with buildings responsible for 40% of the total European energy consumption and a third of CO2 emissions. To help address climate change, the European Commission has set specific targets to be achieved by 2020, known as the 20/20 targets. These targets are to reduce energy consumption by 20%, reduce CO2 emissions by 20% and provide 20% of the total energy share with renewable energy. In order to help the construction industry reach the 20/20 targets and achieve energy neutral buildings and districts by 2050 the European Construction Technology Platform has set up the Energy Efficient Building European Initiative, steered by the Energy Efficient Buildings Association founded in November 2008. This is a Europe wide industry driven research and demonstration programme for energy efficient buildings and districts, with the ambitious vision that all European buildings will be designed, built or renovated to high energy efficiency standards by 2050.

1. Structural heat insulation

Our Structural Insulated Panel (SIP) walls have been designed to maximise energy efficiency. The wall thickness is adjusted according to the climatic region. The wall materials have been optimised to achieve maximum thermal insulation. (SIPs) are one of the most airtight and well insulated building systems available, making them an inherently green product. An airtight SIP building will use less energy to heat and cool, allow for better control over indoor environmental conditions, and reduce construction waste.

• SIPs Save Energy

Building with SIPs creates a superior building envelope with high thermal resistance and minimal air infiltration.

• ORNL blower door tests reveal that a SIP test room is 15 times more airtight than its stick framed counterpart with fiberglass insulation.
• Up to 40% of a home’s heat loss is due to air leakage.
• SIPs have demonstrated amazingly low blower door test results when properly sealed. Based on the reliable performance of SIPs, ENERGY STAR chose to eliminate the required blower door test for SIP homes to meet ENERGY STAR standards.

• SIPs Save Resources

The major components of SIPs, foam and oriented strand board (OSB), take less energy and raw materials to produce than other structural building systems. SIPs are also fabricated in a controlled environment, allowing for greater efficiency than site-built framing. The NAHB estimates that the construction of a 2000 sq. ft. home produces 7,000 lbs. of waste. SIPs have the ability to drastically reduce the waste generated during construction by using advanced optimization software and automated fabrication technology to ensure the most efficient use of material.

• OSB is manufactured from fast growing, underutilized, and often less expensive wood species grown in carefully managed forests. The OSB production process uses small wood chips and highly automated machinery, making OSB a very efficient use of raw materials.
• About 85-90 percent of a log can be used to make high quality structural panels, and the remainder – bark, saw trim, and sawdust – can be converted into energy, pulp chips or bark dust.

2. The airtight building envelope

Convection is a form of heat transportation: Warm air rises due to the thermal lift, "presses" against the building envelope and escapes uncontrolled through leakages. To prevent heat loss in this way an air and windtight building envelope is essential. Low energy and passive buildings must be constructed permanently airtight. The blower-door test serves to proof this. To create the airtight building envelope in most cases vapour control layers are applied to the warm side of the insulation; overlaps and penetrations are sealed without gaps and the joint to the masonry is made. The airtight building envelope has, however, another important function: Large amounts of water vapour are produced in households by exhaled air, cooking, bathing. A family of four produces about 15 l of water per day in this way. Professionally sealed vapour control layers ensure that this moisture does not get unimpeded into the insulation, impairs its function and causes dangerous mold formation in the construction. Moreover, these layers prevent heat loss by convection due to which up to 40% of the heating energy go lost.

3. The windtight building envelope

The windtight building envelope is created by the breathable membrane and permanently sealed facade membranes. Unlike airtight sealing, windtight finish of the building envelope is not required by law. When the envelope is not windtight, cold outside air can easily cool down the insulation. Furthermore snow, rain, insects and wood pests can enter the construction unhindered and damage it. For this reason, the building owner is well advised to ensure sealing of the windtight layer without gaps. Consistent planning and professional creation of the air and windtight building envelope when building a house or renovating pays off. The finish of the outside wall will be determined by what is appropriated with regard to the local surroundings and council regulations. On the inside there is a service void for all the services such as electric cables and water pipes. These voids can also be further filled with an insulation material in order to get an even higher insulation value. This void is covered with OSB plus plasterboard or a panel made with cob which gives a pleasant living climate in the room. Cob is hydroscopic meaning that when there is a high humidity in the air it stores the extra humidity and when there is low humidity it gives the stored humidity back to the air.