Real Life LEED is back! Hope the withdrawal wasn't too harsh. I'm looking forward to relieving some of what I'm calling 'killer post constipation' (AKA my post ideas backlog... sorry for the mental image), so be sure to come back soon!
A colleague of mine is working on a LEED project where an existing building on site has been determined not worthy of renovation and is slated to be demolished. Being the good environmental stewards we are (and having a desire not to ruin chances of earning MRc2, Construction Waste Management later on), I was tasked with searching for information about the relative costs and considerations between conventional demolition and the more sustainable deconstruction process.
Not a deconstruction fan
As reported in a Northeastern study discussed further below, the three primary drivers of the costs and returns on a deconstruction project are (1) labor costs, (2) disposal costs, and (3) the resale or donation value of the salvaged materials. An excellent article out of Remodeling magazine unfortunately determined that "there is no rule of thumb or average square footage cost", as there are too many variables to really make this useful. From articles I've seen across the interwebs, deconstruction premiums can range from a first cost savings to a 200% increase (see the case study on the last page of the Remodeling article), but these premiums are frequently offset by material values. I've seen enough figures citing a 15-30% premium (before salvaged material sales) over conventional demolition costs to feel comfortable giving that figure to a client, with huge non-committal caveats of course.
Commercial Cost Examples
The only commercial cost info I could find was a case study by a Canadian company called Pacific Labour Demolition. On a 6,800 sf office/warehouse building, deconstruction costs showed a 20.9% ($2,128) premium over standard demolition, but that was more than offset by the retail value of the salvaged material at $3,046.
Residential Cost Examples
A recent study out of Northeastern University determined that, at least for residential projects in Massachusetts, "deconstruction costs could be 17-25% higher than demolition costs." For those of you living in Massachusetts and focusing on residential construction, it may be worth shelling out the $31.50 for the full report as it goes on to "identif[y] and rank the parameters affecting these costs."
A study out of the EPA in 1997 (cited here) "estimated the total cost of deconstruction for a 2,000-square foot residence at between $4.50 and $5.40 per square foot, compared to a cost of $3.50 to $5.00 for standard demolition."
In the project my colleague asked about, there is plenty of time to tear down the building before the new one goes up, but it's important to note that it can take substantially more time to deconstruct a building carefully than demolish it with a bulldozer. My friends at the Sustainable Warehouse indicate that "a full [residential] deconstruction project can range from 10-21 days on average, and involves a crew of 2-4 persons." A typical demolition of this scale could be handled in a day or two.
The Non-Profit Model
Everything I knew about deconstruction prior to today's research came from Rebecca O'Brien of The Sustainable Warehouse in Charleston, SC. Since her company is a 501(c)3 non-profit, increased labor costs are offset by tax deductions based on the value of the materials donated to her company. From what I can tell, the non-profit model is common across the nation, though not everywhere. This makes a lot of sense for private owners, as it doesn't require actually selling or reusing materials to recoup costs. Estimated values of products tend to be higher than actual sales prices, meaning a higher tax deduction. This model falls apart if your client is a public entity or someone without any tax liabilities however.
Waste Management Databases
- Building Materials Reuse Association Directory
- National index that lists both contractors and retailers of reused materials. Most of the entries appear to be retailers, though presumably they would purchase materials as well.
- Whole Building Design Guide Construction Waste Management Database
- This nationwide database is designed specifically for typical C&D products, but does not seem to have nearly as many listings as the state indices cited above.
- South Carolina's Center for Waste Minimization Index
- A frequently updated database organized by SC DHEC that allows you to freely search for companies that accept and process a variety of materials. Though not specifically designed for C&D waste, multiple product categories related to such materials are listed.
- North Carolina's Recycling Markets Directory
- Similar to the SC index above, this directory profiles North Carolina based companies and is operated by NC DENR.
Though I haven't looked, there is probably a similar local index for your state... I suggest googling 'YOUR.STATE waste management database' and seeing what pops up. The SC database is far more inclusive than the national ones above.
Did I miss anything? Let everyone know by leaving a comment!