Many Milford residents and area preservationists strongly object to the proposed demolition of the Sanford-Bristol House (c. 1790) by owners Gwendolyn and William Farrell (Mr. Farrell is Planning and Zoning Board District 5 candidate, and Milford Historical Society 1st Vice President), primarily on the grounds of the historical-cultural value of this unique, 18th century home. However, I'd like to express my own objection to this home's demolition, here in terms of purely environmental considerations – a viewpoint that has not yet been surfaced in this debate.
Most of us realize intuitively that rehabilitating and reusing an existing building likely results in a lesser negative environmental impact than replacing it, but seldom do we see these two scenarios compared quantitatively. Yet, the U.S. Advisory Council on Historic Preservation (U.S. ACHP) has a well-established set of standard calculations for doing such comparisons, and their formulas have been incorporated into several "green building" calculators, published by the TheGreenestBuilding.org.
If we apply these calculators to specifications of the Sanford-Bristol House and its proposed replacement home, they reveal that tearing the original house down and building the new one will incur a net energy expenditure of approximately 3,009 MMBTU (millions of British Thermal Units), which carries a carbon debt equivalent to about 218,257 pounds of carbon dioxide. That's the quantity of carbon dioxide produced by an average, U.S. single family home over the course of about 83 years, a time span that most likely exceeds the expected, useful life of the Farrell's new, replacement home. The tear down will also generate on the order of about 137 tons of solid waste, most of it being the remains of the Sanford-Bristol House itself.
By comparison, were the Farrells to rehabilitate the Sanford Bristol House instead, these standard calculations show that, even for an extreme, hypothetical estimate of 90% of the Sanford-Bristol House needing to be rehabilitated, no more than about half the above carbon debt would be incurred, and the resulting construction waste would only amount to about 5 tons. These values illustrate that rehabilitation of the Sanford-Bristol House is an environmentally friendlier ("greener") alternative to demolishing and replacing it with new construction.
Many of us in the broader preservation trades community have studied this situation quite closely, and almost none of us are convinced that demolition of the Sanford-Bristol House is strictly necessary. Furthermore, in its demolition, not only would Milford lose an irreplaceable historic and cultural landmark, but our environment would also be required to absorb yet another unnecessary burden. Here in the United States, where the building industry currently consumes about 40% of our fossil-fuel-based energy production (half of which is wasted), and likewise generates about 40% of our solid waste, we really need to think seriously about conserving our built heritage, rather than perpetuating this cycle of endless tear down and new development.
[ A detailed account of my investigation using the U.S. ACHP models and green building calculators, complete with source references, can be found at: http://birminghampoint.co/blog/2013/09/03/sustainability/environmental-impact-of-demo-replace/ ]
John Poole
Preservationist/Architectural Historian
Derby-Ansonia, Connecticut
