Recycling Buildings: Preservation & Energy Conservation
Green buildings boast lower annual operating energies- the energy required to maintain and operate a building over its life cycle. Regardless, we must recognize that new construction, no matter how green, requires tremendous outlays of energy. At the most fundament level,
Historic buildings are green because they already exist.
The concept of embodied energy helps to better focus this idea. Developed during the energy crisis in the 1970's, the embodied energy concept describes the amount of energy 'invested' or 'embodied' within an existing building.
For example, think of an existing building– Now imagine the amount of present-day energy it would take to build a replacement building of the same size and of the same materials.
It takes energy to:
All of this energy makes up the 'Theory of Embodied Energy.'
"The most responsible way to buy clothes is to shop at Goodwill. And the most responsible way to build is to recycle an old building."
Sustainability by the Numbers
An existing 50,000 square foot building, typical size on an average Main St...
Represents 80 million BTUs embodied energy, equivalent to 640,000 gallons of gasoline
Demolition of such a building would result in 4,000 tons of waste
If only 40% of materials are retained, it would take 65 years for a new green, energy efficient building to recover the embodied energy lost. Many new buildings have a life cycle of far less than 65 years.
The construction of a new 50,000 sq ft commercial building would release about the same amount of carbon into the atmosphere as driving a car 2.8 million miles, or around the globe 112 times.
The greatest threat to older and historic buildings proves to be demolition.
Demolition by the Numbers
Globally our current building stock consists of around 300 billion square feet. A 2004 Brookings Institution report projects that
82 billion square feet of building material in our landfills is the equivalent of 2600 football stadiums full of debris.
The energy needed to demolish and rebuild that estimated 82 billion square feet . .would power the state of California (the 9th largest economy in the world) for 10 years.
Today approximately 25% of the material being added to the landfills is demolition and construction waste. With the excessive amount of waste our country produces each year, we cannot afford to simply bulldoze and build anew.
Donovan Rypkema on Unsustainable Demolition