MAKING A SUSTAINABLE EFFICIENT WALL
The construction industry is one of the largest in terms of employing manpower and volume of materials produced (cement, brick, steel and other materials). Demand and supply gap for residential buildings is increasing every year. Minimizing the consumption of the conventional materials by using alternative materials, methods and techniques can result in scope for considerable energy savings as well as reduction of CO2 emission. The modern tendency is to use energy-intensive material in buildings such as aluminum, steel, and glass. Hence, the consumption of these metals should be kept to a minimum, in order to keep the energy in a building low. It is important to look for alternative materials with low embodied energy.
Buildings must be designed according to the bioclimatic architecture for the minimization of the energy needs and the environmental impact of them, using new heat-insulating materials and special glasses (e.g. smart windows), which reduce effectively thermal losses during the winter and energy consumption for cooling during the summer. Under these aspects, the prospective energy savings in the buildings (especially in the new buildings) can be more than 50% of the energy consumption of standard buildings and become a regular procedure for the built environment construction. When we walk into a building, we often overlook the basic premise of what that building is actually doing. A building, by its simplest definition, is an environmental separator that maintains a barrier between the interior and exterior climates of a space. The second law of thermodynamics explains how a building can maintain climate control through its wall insulation; differences in temperature, pressure, and density tend to even out after a while.
Where’s the wall part come in?
According to the aforementioned law, energy is transferred to areas that have less energy. In the realm of building insulation – if you’re air conditioning your building, moisture will go from the outside of the insulated space to the inside and if you’re heating your building, moisture will go from the inside to the outside. Temperatures try to even out, simple as that. This concept becomes valuable when designing a building that can exist in all types of climates. A so-called ‘perfect’ energy-efficient wall should work, in fact, in all types of climates. This ‘perfect’ wall consists of different layers that handle the results of the climate. A water control layer, an air control layer, a vapor control layer and a thermal control layer must exist within this wall to optimize the efficiency of its insulation. The order in which these layers exist is extremely important. Water must be considered over all else because it is difficult to control followed by air, vapor and then thermal transfer protection in the best place…the outside. The moisture control layer of an energy-efficient wall (usually a breathable house wrap-type material) is, therefore, the first layer outside of a wall. An energy-efficient approach today is to place the thermal control layer outside that, outside the framing. The cladding of the wall would rest on the outside of these control layers, with the structure (framing) of the wall being on the innermost side. Outboard, continuous insulation is key to a sustainable wall that can be optimized in all types of environments.