The most common materials used in low-rise (6 storey) structures in China are brick (supporting walls) and concrete (foundations, posts, loops beams, floors and roofs). Brick structures with concrete foundations are built at an extremely low cost due to the abundance of low cost labor and cheap bricks. Although the system is cheap, it is surprisingly very time consuming to build! A recent study completed by Chreod for FII entitled Opportunities for hybrid WFC solutions in China's urban housing market revealed that it takes between 7-9 days to construct each reinforced concrete floor which includes building the formwork, laying out the steel grid, and casting the concrete.
Four species, White Spruce (Picea glauca), Engelmann Spruce (Pice aengelmannii), Lodgepole Pine (Pinus contorta), and Alpine Fir (Abies lasiocarpa) comprise the spruce-pine-fir species group. All yield high grade timber with relatively small, sound tight knots. Lumber produced from spruce-pine-fir Species is marketed together as SPF.
SPF is ideal for residential and commercial construction due to it's low cost and high strength to weight ratio. Western SPF lumber tend to be available in larger sizes than eastern SPF due to the climate and size of logs. The combination of the species and growth conditions in western Canada result in tall straight trees which produces strong straight lumber that when dried correctly is stable and ideal for construction.
SPF has been used extensively in North America for structural applications in wood-frame construction – the construction method of choice for almost all single-family homes. And now, countries in Europe and Asia seeking economical and durable construction to replace aging or damaged housing or to house growing populations are looking to wood-frame construction and SPF for practical solutions.
Wood-frame construction most often takes place on site, but there are many cost and quality advantages to using premanufactured components such as trusses and walls. A number of Canadian manufacturers make prefabricated buildings and building components and SPF lumber is the primary building material of choice. Buildings and building components such as wall and roof panels can be compactly packed in containers and shipped economically.
Whether constructed on site of from premanufactured components, wood-frame construction is a fast, light, proven way of building houses, apartments and even commercial buildings. It is supported by a vast amount of research and testing to meet the most difficult climatic conditions. Wood-frame construction offers the following benefits:
Increased thermal performance: Wood-frame construction is easy to insulate to RSI 2.62 or higher, meaning increased resident comfort and much lower heating and cooling costs over the life of a building.
Architectural flexibility: It is economically feasible to add offset walls, balconies, alcoves and other features that add interest and appeal, especially for roofs.
Space economy: Wood-framing is compact – structure, insulation, air and moisture barriers and exterior and interior finishes are contained in a small, light-weight space.
Durability: There are many examples of wood buildings that have lasted hundreds of years, and modern wood-frame construction is better equipped than ever to last at least as long as a building is still meeting the user's needs.
Ease of installing electrical and mechanical services: Interior wall and floor cavities are used to route vertical and horizontal services, including electrical wiring, plumbing, and heating ducts.
Affordability: The major reason why wood-frame construction has been so successful in North America, and is being considered by many countries to solve housing challenges, is its affordability.
Construction speed: Wood-frame construction is fast – it is normal for an experienced crew of three to frame one floor per day per unit. In countries where wood-frame construction is new, an adaptation period is required before the speed of wood construction can be realized. In these countries, wood-frame construction can still offer initial savings in time and costs, and greater savings as familiarity builds.
Meeting building codes: Based on research and testing, wood-frame construction meets or exceeds building code requirements for strength, sound transmission and fire safety.