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CALCULATE YOUR CONSTRUCTION WASTE REDUCTION POTENTIAL

Conversion Factors
Computing Waste Amounts
Potential Savings Calculation
Additional Resources
Evaluating volumes and recycling potential for construction waste recycling is an imperfect science. However, there are ways to estimate how much waste you have, and how much disposal is costing you, so you can evaluate its potential for reduction, reuse or recycling.

Conversion Factors

One of the trickiest parts of evaluating your construction waste stream is in the various ways it can be measured - weight or volume. Both are acceptable methods, however, the numbers could be deceiving. Take for example, cardboard and drywall. A cubic yard of cardboard will only weigh about 30 pounds while a cubic yard of drywall will weigh about 400 pounds. Therefore, a full 30 yard dumpster of cardboard will only weigh about 900 pounds. A 30-yard dumpster full of drywall will weigh about 12,000 pounds. The important thing is to use consistent units. The following table, adapted from National Association of Homebuilders will help with conversions from one unit of measure to the other:
 

Material

Pounds per Cubic Yard

Cubic Yards per Pound

Solid Sawn Wood

267

0.004

Engineered Wood

280

0.004

Drywall

400

0.003

Cardboard

30

0.033

Metals

150

0.007

Vinyl (PVC)

150

0.007

Masonry

1000

0.001

Paints, Caulks, etc.

167

0.006

Mixed Wastes

95

0.010

* Source: NAHB Research Study - "Residential Construction Waste: From Disposal to Management (April, 1995)

Computing Waste Amounts

In 1998, a project was tracked in Park City, Utah. The construction was of a 4,300 square foot single family home with a three car garage. For the duration of the project, a total of 7 dumpsters, 15-yards each, were hauled to the landfill for a total of approximately 108 cubic yards. Using the conversion chart above, total pounds were calculated based on the observed material percentages (estimated on-site). The following table shows the results:
 

Material

Percentages 

Cubic Yards

Solid Sawn Wood

25

27

Engineered Wood 

20

22

Drywall 15

16

Cardboard

12

13

Metals

3

3

Vinyl (PVC) 

1

1

Masonry

1

1

Paints, caulks, etc. 

1

1

Other

22

24

Total

7 Loads
15 cu yards each

108


Landfill fees are often charged per ton (1 ton = 2000 pounds), so the Park City project converted the waste composition data into pounds for ease in calculating potential from avoided disposal costs. Converting cubic yards to pounds isn't difficult, using the conversion factors:

Material

Cubic Yards

 = Pounds

Solid Sawn Wood

27

267

7209

Engineered Wood

22

280

6160

Drywall

16

400

6400

Cardboard

13

30

390

Metals

3

150

450

Vinyl (PVC)

1

150

150

Masonry

1

1000

1000

Paints, caulks, etc.

1

167

167

Other

24

95

2284

TOTAL    

24210


Potential Savings Calculation

The following example shows the estimated landfill savings derived from C&D recycling and/or reuse:

Item

%

Waste Tons

Diverted Tons

  No Recycling/Reuse  
Tons of C&D Waste 100
100
0
Landfill cost per ton ($50)  
$5000
$0 cost savings
   
  With Recycling/Reuse  
Tons of C&D Waste 100
Wood  45
0
45
Drywall 15
0
15
Cardboard 2
0
2
Metals 3
0
3
Other - mixed waste 35
35
0
Landfill cost per ton ($50)  
$1750
$3250 cost savings

This estimate is a direct financial calculation of savings due to reduced landfill costs associated with reduced disposal needs. It provides a good rough estimate of potential savings and is the first step to preparing a C&D waste management plan. This estimate does not include the savings in landfill space (community/tax savings), nor does it include the money that could be derived from reselling items such as cardboard or wood.  It also does not include costs associated with employee/subcontractor training, material hauling, or time spent finding markets for recyclable materials. All of these factors will be weighed as a C&D waste management plan is developed. The calculation of this estimate for a particular company will likely indicate that a plan should in fact be developed to reduce material waste and reuse or recycle what can not be avoided.


Additional Resources:
 
The Construction Waste Management Handbook provides a step-by-step discussion of a construction waste management plan developed and applied by The Homestead Habitat for Humanity (HHFH) at their Jordan Commons development. The handbook includes details on the calculation of disposal costs (potential savings), waste composition, identification and selection of recycling and reuse outlets, on-site training, material sorting procedures, and more. A must-read for anyone interested in developing a construction waste management plan. National Association of Home Builders Research Center
        - http://www.smartgrowth.org/library/constwastemgmt_hndbk.html
Calculating the Cost-Effectiveness of Jobsite Recycling - Are there dollars in your dumpster? This site provides a series of worksheets to help determine how much of what materials are produced at the job-site, and the cost of recycling versus disposal. King County Department of Natural Resources
- http://dnr.metrokc.gov/swd/bizprog/sus_build/analyze.htm

 

(Fact Sheet 4 of 10)

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