How Does Your Building’s Envelope Affect Sustainability
Sustainability is more than a buzzword. It’s part of our future. As an architect or contractor, you are hopefully working to make all projects more sustainable, but it’s hard to keep track of all the things you can do.
One of the things to consider is the building’s envelope, the physical interface between it and the world.
What Is Building Sustainability?
Building sustainability, also called green building or sustainable building, means creating structures that are designed to be more sustainable and efficient throughout their entire life, from initial build, through operation, and to eventual demolition. This might include using reused or recycled materials, improving insulation to reduce energy use, landscaping to collect stormwater runoff, etc.
What Factors Affect the Overall Sustainability of a Building?
A variety of factors affect a building’s sustainability, but there are three major areas builders typically consider:
- Efficient use of resources. This starts with material selection and moves through design. A sustainable building uses less energy, water, and nonrenewable resources.
- Protecting occupant health. This includes natural lighting and good ventilation.
- Reducing waste and pollution.
Another thing to consider is economic sustainability, which includes worker safety and paying a good wage. Incorporating renewable energy from the start, such as solar systems, can be cheaper than retrofitting it later. For some buildings, geothermal heating can make a huge difference. You should also consider how far building materials have to be shipped. There is a reason buildings in the English Midlands are brick (good clay) and in the West Country stone.
How Does The Envelope (Curtain Wall) Affect the Overall Sustainability of the Building?
The envelope affects the overall sustainability of the building in two ways: Materials used and design.
For example, wooden buildings, in some climates, have exceptional thermal inertia. This means the interior tends to stay closer to the same temperature, reducing heating and cooling costs. This both uses less energy, which also reduces pollution, and improves occupant health by supporting comfort for those living and/or working in the building. Metal roofs are generally considered the most sustainable because of their extreme durability and storm resistance. A good metal roof can last fifty to sixty years.
Locating windows to capture natural light can reduce the amount of power used and also improve the mood and mental health of occupants.
What Is a Sustainable Envelope?
A sustainable envelope is one which:
- Contains reused or recycled materials when appropriate
- Uses local materials as much as possible to save on transportation costs
- Uses durable materials that will not have to be replaced as often
- Incorporates passive solar design to provide heating and/or open ventilating to provide cooling
- Incorporates insulation to reduce heating and cooling needs, as well as an air barrier such as sheathing
- Locates windows and skylights to provide maximum natural light
- Reduces moisture transfer through the building, reducing mold growth
- Controls outside air, preventing drafts and moisture, and protecting occupants from outdoor pollutants
- Includes modern HVAC systems to improve indoor air quality and control germs
- Incorporates high-performance window features such as triple glazing, low-emissivity coatings, and dynamic glazing.
- Includes an effective drainage system.
Including these features in new builds increases the value of the building, extends its life, and supports the environment and health. Some features can also be retrofitted during renovation. New windows can incorporate high-performance features, with even double glazing alone providing substantial benefits.