Plastic Bags and Preservation

Our city has just made a new year's resolution – As of January 1 we are all now bringing our own bags to the store.  This step forward in our increased awareness of what we are throwing away reminds me of a talk given by my favorite preservation economist (what, you don’t have a favorite?).  In HSI's 2015 “Mightier Than a Wrecking Ball” conference Donovan Rypkema stated the following:

“Every time a little 2200 sf house…would have been rehabilitated instead of raized…that would have more environmental impact…then all of the plastic bags that 440 people would have used in their lifetime.”

With the new plastic bag ban, does this mean much to us here in Salem?  It is certainly clear that demolishing a house means that the bulk of the building material will end up in the landfill (with some recycled, hopefully).  To put it in perspective, a demolished 2,200 sf house (with cellar and attic space) will become 297 cubic feet, or 7.4 construction dumpsters of landfill. (source)   That is the same as me generating household trash for 354 years.  (calculator)  

What goes into the dumpster, in addition to volume of debris, is the energy once used to make those materials (called embodied energy).*  Fuel once used to mine, harvest, manufacture, ship and install are all wasted when a building is demolished.  Then, there is the intensive energy needed to build a new house.  Rypkema also highlighted a study that showed:

To build a new home on a clear site uses 182 tons of material energy (this includes energy used to extract, create, ship and discard the materials).  To demo an old house, haul it to a landfill and rebuild with LEED gold architecture standards used twice as much material energy - 351 tons.  However to rehab a historic house uses only 47 tons of material energy.  Seven times less than demo-ing and rebuilding “energy-efficiently".
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For a community like ours, which is making important efforts towards sustainability and resiliency, it makes a lot of sense to celebrate the tradition of re-using our historic buildings.  Certainly, a vibrant city will always be changing - some buildings will be replaced over time.  When evaluating the need for demolition by weighing the social, historical or cultural value of a building against the financial goals and community need delivered by the developer it will serve our community well to also include the quantifiable environmental impacts of “recycling” (reusing) old buildings in the equation. 
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Now that Salem has implemented a plastic bag ordinance, mandatory recycling, and solar rooftop programs, among other programs, the city can continue to advance environmental concerns by insisting that new buildings are built to last (with quality design and construction); that we continue to repurpose existing buildings; and that we maintain the buildings we have, extending their lives into the next century.

​*If we are going to be fair many homes in Salem were built before fossil fuels began to be used in earnest.  While some materials in my 1850s house were shipped or processed using coal power much of the mining, harvesting, manufacturing and site delivery was done with hydro, livestock or man power.  Historic houses were LEED certifiable before it was cool!  That said, throwing away dumpsters full of heavy-labored and hand-crafted building materials that came from virgin forests shouldn’t make anyone feel warm and fuzzy.