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Michael Green

Posted: 
November 12, 2013

 

by Bernie Desjardins

In the past, most Canadians made their homes in rural areas, but today, the opposite is true. The percentage of Canadians living in cities continues to increase, and the trend in urban planning is towards greater densification. This means more tall buildings, and Michael Green intends to build them from wood—he envisions wood-structured buildings of 30 storeys.

Is he not afraid that the wind will blow them down? Is he willing to risk a “towering inferno” the likes of which this world has not yet seen? What about earthquakes? In reality, the “Big Bad Wolf” is not a serious threat, and very safe, tall buildings can be made using wood as the primary structural material.

Michael says that the large members used in modern wood construction form an insulating, protective “char” layer in the event of combustion, resulting in an excellent fire-resistance rating. Also, non-combustible material can be affixed to the undersides of wooden floor panels, further reducing susceptibility to combustion. As for the ratio of weight to strength, engineered wood products are comparable, and sometimes superior to reinforced concrete. When the typically erroneous perceptions of tall wood construction are dispelled, people will surely welcome the trend towards the increasing use of structural wood in large buildings.

Finding the Forest Through the Trees (FFTT) is a method of construction developed by Michael Green Architecture (MGA). Presented in The Case for Tall Wood Buildings: How Mass Timber Offers a Safe, Economical, and Environmentally Friendly Alternative for Tall Building Structures, a report authored by Michael Green and J. Eric Karsh, the FFTT system uses wood as an alternative to the structural components that are normally found in multi-storey buildings.

The idea behind the FFTT name is that rather than focusing on the small stuff (although it too is important to remember), we need to look at the big picture. We need to make big changes—comprehensive, systemic changes—to tackle the huge challenges we face in terms of exploding global housing demand and a changing climate.

For more than a century, tall buildings have been made from steel and concrete, and little has been done to change this, which is why Michael’s innovative construction system can be seen as revolutionary.

The notion of building wooden skyscrapers raises a number of questions in addition to those concerning safety. Don’t trees sequester (store) CO2 that they extract from the atmosphere? How can it be good to cut down more of them for use in construction? It is true that old-growth trees are irreplaceable within our lifetime, if ever, and that we have already cut down too many of them. However, the wood material used in the FFTT system is taken from fast-growth species such as birch and aspen. Michael explains that his approach is based on sustainable forestry rather than deforestation, this being a crucial distinction that must be made by those wishing to understand how the increased use of wood in construction can be justified. Michael says wood is really the only “green” building material out there because CO2 is sequestered while the trees grow; any trees cut in Canada must, by law, be replanted.

Besides potentially reducing energy consumption and greenhouse gas emissions, FFTT has another important benefit: in terms of economic diversification, it will increase value-added production in our forest industry—something that is good for all Canadians. In the past, the size of traditional dimension lumber used for massive columns and beams in large buildings was only attainable from very large trees, but for such applications, dimension lumber has given way to mass timber products. The manufacture of these materials is increasing in Canada and offers promising export potential. Whereas the size of wooden building components was once limited by the size of the trees used, incredibly large structural composite lumber products can now be made. Very strong, massive structural members can be produced in diverse shapes and sizes by gluing together pieces of precisely planed dimension lumber arranged in layers. This product is called glulam. In addition to its size and strength, glulam has a very appealing, natural wood look that can be used to enhance the appearance of both the interior and exterior of a building. Another structural composite lumber product is cross-laminated timber (CLT). CLT panels can be 40 ft. long, 10 ft. wide, and up to 2 ft. thick and are currently being used for floors, walls, and roofs in mid-rise construction projects.

As big as they are, the size of such panels will likely increase in the future. Like glulam, they can be left exposed within buildings to provide astounding aesthetics and eliminate the need for and expense of other types of finishing work—people almost invariably love the feel and look of real wood. Whereas the use of steel and concrete in highrises has been perfected over the past century, the use of mass timber products for tall buildings is still in its technological infancy. Michael Green believes that with refinement of methods and other improvements leading to cost reduction, wood-based highrise construction will ultimately out-compete steel and concrete in terms of cost—it already is, in some instances. Labour and process costs are much lower using mass timber products because factory-based prefabrication significantly reduces construction time.

Michael’s work has spurred interest in the potential application of CLT and other structural composite lumber products to low-rise construction, and to modular construction. Prefabricated panels, beams, and columns have the potential to increase the efficiency of modular building processes even further—processes that already offer the most efficient method of construction, according to researchers at the University of Alberta and other institutions.

Step into one of Michael Green’s buildings and you too will see the forest through the beauty and warmth of the wood displayed in these technologically progressive structures. You won’t forget the trees.