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Recycle Construction and Demolition (C&D) Debris
Construction Waste Handbook
Worksheet Economics
C&D Resources
Education Program
Overview
The plan from the onset for House Two was built around the concept of trying to dramatically reduce the amount of waste going to the landfill. The house was going to be of similar size as the House One Audit house (7,789 versus 7,929 square feet) and was going to be constructed by the same builder and sub contractors. In the intervening time from the onset of the audit of House One, HARC had investigated many alternatives including on-site separation, off-site separation, on-site grinding, transfer and a mixed approach. HARC floated the notion of evaluating one of the recycling methodologies we had found in the literature search, on-site grinding. HARC approached first the builder and secondly the H-GAC staff. Mr. Cox clearly stated his desire to try and find an alternative method to what he had always done with hauled waste.
HARC itself had become fully convinced that one of the early options considered, on-site grinding, was in fact a methodology that made perfect sense in the instance of this large custom home. We made Mr. Cox aware of the option, provided literature and set up a meeting with representatives from Belleau Wood Environmental, LTD., a Houston area business and its owner Mr. Joe Collett. HARC asked Mr. Collett to make a presentation to Mr. Cox on the on-site grinding methodology. As it turned out, this was a little more difficult to coordinate than we all thought.
Mr. Collett is a distributor for Packer Industries and a service provider for on-site grindings. Ultimately, Mr. Cox granted his consent to investigate and apply the methodologies of on-site grinding to the second site he had provided. He made his construction superintendent the prime contact and we had an agreement July 26, 2004 to begin the process. We then secured the permission of H-GAC to conduct this limited test of the methodology for evaluation. Mr. Collett graciously donated his time, his firm's labor, technical resources, and his knowledge to this project and the objective of testing on-site grinding in the H-GAC area.
During the months of July and August the site preparation and foundation work was taking place with sand, rebar, post tension cable and the forming lumber showing up on the site. The second house was located at 234 Angel Leaf, The Woodlands, Texas, Montgomery County. The house was a 7,789 square foot two-story house with a swimming pool. The slab was poured on August 3, 2004. According to the agreement the builder would conduct a version of on-site segregation of the materials jointly identified to be ground on-site: these were wood, cardboard, shingles, bricks and drywall.
It was also the case that on-site grinding would not and can not address every need in the new construction waste stream thus, there would be a requirement for the project to have a 30 yard roll off container in place to handle the material that could not be ground and applied (recycled) on-site. HARC contacted the waste contractor BFI. Inc. and ordered another container to be delivered. The roll off was set in place September 21, 2004.
 Figure 46. Roll off container arriving at House Two Click image above for a hi-res version |
On-site Grinding - Grind One
The first day for experimenting with on-site grinding machinery was September 8, 2004. The H-GAC staff was invited to attend and witness the process in action. In accordance with the plan, the builder had segregated the wood waste stream on-site with the intention of expediting the grinding process on the grinding day. Mr. Tom Cox and Builder Bob, the construction superintendent, had done a great job assembling the foundation forming wood and the frame package wood wastes as well as some of the roof decking. Mr. Joe Collett, the President of Belleau Wood Environmental, LTD. arrived on-site with his crew and his grinding machinery. The device used in the test was a Packer Industries Inc. Model 750 grinder. Packer Industries is located in Mabelton, Georgia.
The site was holding about all of the solid sawn wood that it was capable of handling when the day began. In the figures below, the materials can be viewed quite easily. The builder had implemented his program of isolating the wood wastes on-site in anticipation of the grinding process. The builder was very creative in terms of where and how they stored the solid sawn wood waste. On this large lot this plan worked very well.
 Figure 47. Solid sawn wood storage on-site anticipating the grinder Click image above for a hi-res version |
 Figure 48. Solid sawn wood storage on-site anticipating the grinder Click image above for a hi-res version |
The materials were transported from their locations on-site to the grinder via a bobcat with a one cubic yard bucket. The size of the bucket is important because the intake throat on the grinder feeds a grinding hopper that has a one cubic yard capacity. The segregation of the wood makes the process move very quickly for the team and the entire process was observed with close scrutiny.
 Figure 49. Bobcat and grinder with H-GAC staff Click image above for a hi-res version |
 Figure 50. Bobcat and grinder with H-GAC staff Click image above for a hi-res version |
The table documenting Grind One shows two critical points. First, the volume reduction from bulk waste to ground waste is a little more than a 3 to 1 ratio and secondly, the grinder virtually eats the material quicker than one would imagine. The typical grind time for a three quarter yard load of wood was 4 minutes. It is the case that this particular machine makes use of a magnetized belt in the feeding process so that the post-grind wood is not contaminated with any metal wastes, whether it is nails or joist hangers. The metal is simply segregated out into a bucket for recycling with the appropriate metals recycler.
Due to the grinding, 53.75 yards of solid sawn wood primarily from the forms and frame packages was reduced to 17.67 yards (30% of original dimensions). This was accomplished in a total of 308 minutes of grinding time on the machine. Note that this is different than total elapsed time for the day of grinding. Additionally 8.5 yards of TechShield, a foil fronted radiant barrier manufactured by Louisiana Pacific, and cornice were reduced to 1.5 yards (18% of original) in 40 minutes of machine grind time.
 Figure 51. Pre-grind wood Click image above for a hi-res version |
 Figure 52. Post-grind wood Click image above for a hi-res version |
 Figure 53. Pre-grind wood Click image above for a hi-res version |
 Figure 54. Nails separated during the grind Click image above for a hi-res version |
Alternative to Crushed Concrete for Site Stabilization
HARC and Mr. Cox had previously decided that the wood waste would be ground and applied directly on-site as a silt fence application, soil improvement, or as a general site improvement material. This was a conscious choice consistent with the manufacturer's recommendation and that of Mr. Collett. It is the case that some builders do harvest the ground wood and transfer it to another site or apply it to the site at a later stage. The philosophy behind the chosen and preferred tactic is that residential construction sites are notoriously known as mud pits where everyone struggles with the mud. The result of this struggle is that many days of work are lost as a result of the site conditions. In another study, researchers found that up to 16 days of time in schedule could be recovered when a wood chip mat was widely employed to create a working and lay-down area. Recall that in House One, that builder had to purchase nine (9) loads of crushed concrete to gain and maintain access to the site at a cost of more than 500 dollars. This was mainly for access and did nothing to provide working space for the workmen.
The ground solid-sawn wood made a superb mat upon which crafts of all kinds can work in the worst of weather. In light of this fact, this idea was always a part of the plan at this site. While HARC and the builder deployed this strategy at some level the plan but it was not as widely employed as HARC would have preferred. Thus, the actual cost benefit analysis from this approach can not be maximized in this investigation. Although HARC we can fully substantiate the value, the cost savings calculations do not yield the type of results we felt were possible when the mat is fully deployed for all trades on-site.
 Figure 55. Post-grind wood applied as a mud controlling mat Click image above for a hi-res version |
 Figure 56. Post-grind wood applied as a mud controlling mat Click image above for a hi-res version |
The primary reason this underutilization took place was due to a miscommunication between some of the parties. In an attempt to be responsive, the builder asked that the decking, better known as TechShield, be ground so that the amount of material going to the landfill would be greatly reduced. He had seen the 3 to 1 reduction in the solid sawn wood and was favorably impressed. All present tried to discourage this particular request fearing that the material could become commingled with the clean ground wood. Nonetheless, it was done with the result being a partially compromised pile of ground materials and tiny pieces of tin foil in the most inconvenient places. Due to this commingling of material and concerns for the consequences, the amount of mat was reduced. This problem of tiny little pieces of TechShield would confound the project until the very end.
 Figure 57. The mat being created Click image above for a hi-res version |
 Figure 58. Post-grind TechShield Click image above for a hi-res version |
The data for the first grind is incredibly straight forward. The ground material is not a fine grind in the wood version but is more appropriately defined as a fine chip approximately 2 inches long and three quarters of an inch wide. The grind consisted of the foundation packages, frame packages, and the TechShield. 14,418 pounds of sawn dimensional lumber was ground in a total grinding time of 308 minutes. 2,403 pounds of TechShield was also ground. In House Two HARC employed the EPA calculator values for all weights used in the report and actual volumes from a log which was maintained by Belleau Wood Environmental, Ltd.
| House Two Grind One |
| Type of Material | No. of grinds | Grind time (Minutes) | Average time per grind (Minutes) | Approximate Volume Pre-Grind (Yards) | Approximate Volume Post-Grind (Yards) | Volume Reduction (Yards) |
| Frame Lumber | 72 | 308 | 4.27 | 53.75 | 17.67 | 3:1 ratio (36.08) |
| TechShield and Cornice | 11 | 40 | 3.5 | 8.50 | 1.50 | 3:1 ratio (7) |
 Figure 59. Post-grind separated waste materials Click image above for a hi-res version |
 Figure 60. Post-grind separated waste materials Click image above for a hi-res version |
Haul One
The container for House Two was set in place September 21, 2004. Haul One for House Two was completed on October 4, 2004; after the first on-site grinding took place. Haul one consisted of mixed wastes estimated at 2,166 lbs (22.8 cubic yards * 95 lbs/cu yd). The actual container was scaled at 2,120 pounds. The contents of this haul were of the most undesirable material and least likely to be recycled, possibly due to the grinding of the more desirable and recyclable materials. The haul consisted of wet cardboard, plastics, vinyls and painted wooden material.
| House Two Landfill Waste |
| Date | Haul | Weight (lbs) | Details |
| 10/4/2004 | 1 | 2,120 | TechShield, packaging, sheathing |
 Figure 61. Commingled mixed waste contents of Haul One Click image above for a hi-res version |
 Figure 62. Commingled mixed waste contents of Haul One Click image above for a hi-res version |
On-site Grinding - Grind Two
The second grinding day was established as November 5, 2004. The H-GAC staff was again invited to the grind. The plan for the day was to grind the remaining solid sawn wood that been generated in the time since the first grind and the drywall pile. Belleau-Wood Environmental, Ltd., arrived at 234 Angel Leaf at 12:30 pm, and began grinding the leftover wood. Due to a recent rain, the site was extremely muddy and there was an enormous puddle near the drywall pile. To solve this problem, the mulch produced from the wood grind and several scoops of the mulch pile from the earlier grind was used as a mat or pad for the bobcat. The mulch mat allowed easy access for the bobcat to the drywall pile and the grinder and generally made the site much neater.
The brick-laying crew, which was mixing mortar behind the house and carrying it into the house in a wheelbarrow, was greatly aided by the mulch mat walkway. After the pad for the bobcat was constructed, the drywall grind began. The grinder rapidly reduced the drywall pile to about one third of its original volume, and the post-grind material was moved to a pile in the backyard. The grind was really rather easy, even more so than the first grind. 11,600 pounds of drywall was ground and an additional 6,608 pounds of post-grind wood was made available for the site.
| House Two Grind Two |
| Type of Material | No. of grinds | Grind time (Minutes) | Average time per grind (Minutes) | Approximate Volume Pre-Grind (Yards) | Approximate Volume Post-Grind (Yards) | Volume Reduction (Yards) |
| Wood | 40 | 156.5 | 4 | 24.75 | 8.14 | 3:1 ratio (16.61) |
| Dry Wall | 39 | 13.87 | 3.5 | 28.75 | 7.13 | 3:1 ratio (21.62) |
 Figure 63. Solid sawn wood waste for Grind Two Click image above for a hi-res version |
 Figure 64. Solid sawn wood waste for Grind Two Click image above for a hi-res version |
 Figure 65. Mr. Collett on the grinder Click image above for a hi-res version |
 Figure 66. Mat being created Click image above for a hi-res version |
The second grind of wood was accomplished in 157 minutes which is a little more than half of the time that was spent in Grind One. In this grind, 6, 608 pounds or 24.75 cubic yards of material was reduced to a little more than 8 cubic yards of useful material which could be immediately deployed on-site as demonstrated by what had taken place in the set up for the grind. In grind one, 14, 351 pounds of solid sawn wood was ground in machine grinding time of 308 minutes.
From the observations made of the grinding process, the following conclusions can be drawn. First, the grind time for a hopper of solid sawn wood is less than 5 minutes. Second, the volumetric reduction that the grinder provides is greater than 3:1 creating a resource of the material instead of a liability.
The second phase of grind two was to address the drywall on the site. Again, the builder did a great job of storing the waste on-site in preparation for the grind. Approximately twenty-nine (28.75) cubic yards of drywall was on the site that day. The grinder performed beautifully grinding the material into a combination of fine and chipped pieces. To minimize the drywall dust that is created when the material is ground, the machine is fitted with a drape that contains the material in the immediate area of the machine. The grinding time for the 29 yards was under 14 minutes of machine time.
 Figure 67. Stored pre-grind drywall Click image above for a hi-res version |
 Figure 68. The grind pile Click image above for a hi-res version |
 Figure 69. Post-grind drywall ready to be applied to soil Click image above for a hi-res version |
 Figure 70. Post-grind drywall ready to be applied to soil |
Haul Two
The Haul Two container left the site on November 29, 2004. The container consisted primarily of brush from site clearing, including understory/brush and small trees, mortar, TechShield, and wet cardboard packaging. The container load was a full 30 cubic yards. HARC applied the calculator and estimated a total weight of 4,170 pounds. The container was composed of: (1) mixed wastes (20 yards * 95lbs/yd), (2) engineered wood (4 yards * 280 lbs/yd), (3) mortar (1yard * 1000 lbs/cu yd) and (4) cardboard (5 yards * 30 lbs/cu yd). The container passed the scales at 4,000 pounds.
| House Two Landfill Waste |
| Date | Haul | Weight (lbs) | Details |
| 11/29/2004 | 2 | 4,000 | Brush, mortar, cardboard |
 Figure 71. TechShield with foil Click image above for a hi-res version |
 Figure 72. Mixed wastes Click image above for a hi-res version |
 Figure 73. Wet Cardboard Click image above for a hi-res version |
Haul Three
The third and final 30 yard roll off container haul for house two was transported to the landfill on January 5, 2005. The container was very full, consisting primarily of mixed wastes from the final lot clearing, the final understory clearing, and the final house cleaning that had taken place during the holidays. We did not attempt to estimate the weight of the container due to the nature of the site cleanup materials.
| House Two Landfill Waste |
| Date | Haul | Weight (lbs) | Details |
| 1/5/2005 | 3 | 7,100 | Understory clearing |
 Figure 74. Contents of Haul Three Click image above for a hi-res version |
 Figure 75. Contents of Haul Three Click image above for a hi-res version |
On-site Grinding - Grind Three
Grind Three took place after the holidays and after the final roll off container had been hauled. The builder had advised HARC that he was ready to finalize the grind and to get the buyer into the home. The grind was scheduled for January 11, 2005. The H-GAC staff was invited to attend but was unable to make this grind. There were some non-grinder mechanical problems that did not allow the grinder to arrive on-site until after twelve noon on the day of the grind. Thus, the grind actually took place over the course of two days. The builder again had done a terrific job of stacking and storing the material to be ground. This grind was dedicated to the reduction of the waste from shingles, bricks, final wood trim and site wood cleanup.
 Figure 76. Pre-grind brick & shingles Click image above for a hi-res version |
 Figure 77. Hopper loaded Click image above for a hi-res version |
 Figure 78. Loading shingles Click image above for a hi-res version |
There was a great deal of interest in the ability of the grinder to handle the shingles and the bricks using the one cubic yard hopper. These are two very unique materials with properties that might present challenges to a portable grinder. The grinder performed excellently throughout the grind turning bricks into a fine powder and shingles into small shards of asphalt.
 Figure 79. Palletized pre-grind brick Click image above for a hi-res version |
 Figure 80. Stored pre-grind brick Click image above for a hi-res version |
 Figure 81. Stored brick Click image above for a hi-res version |
 Figure 82. Taking bricks to the grinder Click image above for a hi-res version |
The ease with which the site was cleared was a testament to well trained craft persons and a desire to have a job well done. The employees of Mr. Collett worked effectively and efficiently and the bricks were reduced in very little time into a perfect base material for the concrete flatwork that was to follow the grinding day. The functioning of the tractor versus the bobcat was entirely more flexible and was more effortless in loading the hopper. This was an observation shared with the crew and there was tacit agreement that the height of the tractor did aid in speeding along the feeding of the hopper with material to be ground.
There was a remaining feedstock of wood, primarily trim, and some forming material that had to be ground. Having already observed this process and knowing what the grinder was capable of doing; HARC turned its attention to the matter of the application of the materials on site. It was the case that all previous materials that had been ground had been applied on the site with one notable exception: The TechShield. A pile of ground and commingled wood lay in the back yard. This issue had to be addressed. In discussion with the builder a month later it was decided to harvest the material and to landfill the TechShield.
 Figure 83. Grinding of bricks Click image above for a hi-res version |
 Figure 84. Metal harvested Click image above for a hi-res version |
| House Two Grind Three |
| Type of Material | No. of grinds | Grind time (Minutes) | Average time per grind (Minutes) | Approximate Volume Pre-Grind (Yards) | Approximate Volume Post-Grind (Yards) | Volume Reduction (Yards) |
| Wood | 18 | 63.93 | 4 | 18 | 5.94 | 3:1 ratio (12.06) |
| Shingles | 7 | 13.87 | 2 | 7 | 2.31 | 3:1 ratio (4.69) |
| Brick | 32 | 77.32 | 2.50 | 32 | 10.56 | 3:1 ratio (21.44) |
 Figure 85. Close-up of post-grind brick Click image above for a hi-res version |
Summary of House Two
In total, the house generated 87,556 pounds of C&D waste. According to the national average based on NABH studies, a typical 2,000 square foot house generates 8,000 pounds of waste. This is verified in previous studies and confirmed in the Franklin report. This house was 7,789 square foot, two story. If we were to extrapolate the 2,000 square feet to 8,000 square feet one would expect something on the order of 32,000 pounds of C&D waste.
| House Two Total Landfill Waste |
| Date | Hauls | Weight (lbs) | Yards |
| 10/2004-1/2005 | 3 | 15,490 | 84.3 |
This house, however, will not sustain the 87,556 pounds of waste. Because this house utilized the on-site grinding methodology, the house diverted 72,066 pounds of waste from the landfill to its site. This is a diversion rate of 82.30 %. This is a very replicable result for any residential house and is entirely consistent with the national on-site grinding studies cited earlier.
| House Two Total Grind |
| Type of Material | No. of Grinds | Approximate Volume Pre-Grind (Yds) | Weight (lbs) | Approximate Volume Post-Grind (Yds) | Volume Reduction (Yds) | 3:1 Ratio |
| Wood | 130 | 95.50 | 25,766 | 33.17 | 62.33 | 0.34 |
| Shingles | 7 | 7 | 2,800 | 2.31 | 4.69 | 0.33 |
| Brick | 32 | 32 | 32,000 | 10.56 | 21.44 | 0.33 |
| Drywall | 39 | 28.75 | 11,500 | 7.13 | 21.62 | 0.24 |
| TechShield | 11 | 8.50 | 2,261 | 1.50 | 7 | 0.17 |
| Total | 219 | 171.75 | 74,327 | 54.665 | 117.08 |
The pie charts in Figures 86 and 87 below depict the ratios of waste make up for the study house and the national typical house. One of the striking differences in the two charts is the more than 327% increase in the brick component of the C&D waste stream. This is entirely consistent with what was observed in House One. This is significant inasmuch as, according to the EPA calculator, bricks weigh an estimated 1,000 pounds per cubic yard.
The fact that H-GAC area's modern hot and humid houses typically are built with a significant increase in the volume of enclosed space (this was a two story home) leads to this surprisingly large increase in the amount of material required to create the envelope and the resultant interior components such as drywall. This is simply a function of geometry that builders are forced to deal with in this marketplace. To illustrate this point consider the following example, if a wall section is 10 feet high in a modern hot and humid climatic zone house and the comparison circa 1996 national typical is an 8 foot wall section, then 25% more material is required to cover the same square footage of space.
The fact that there is a substantial variance from the national typical model should not come as any surprise due to the response to climatic differences in the nation's typical house versus the typical house in the hot and humid area. The surprise comes in the enormity of the variance. It is curious that the shift in materials (-26%) away from wood and drywall is fully accounted for in the increase in the percentage of bricks and masonry used. We have some opinions about the possible causes of the variance and suggest them in the following observations section.
 Figure 86. C&D waste-stream makeup |
 Figure 87. C&D waste-stream makeup |
Waste stream disposal costs
The total expenditure for waste stream disposal costs totaled $630; $90 to set the containers on the site and $180 per haul for three hauls.
On-site grinding costs were not incurred by the project. Mr. Joe Collett, of Belleau Wood Environment , Ltd. Donated the services and the consulting to the project to achieve the grinding of the materials. The manufactures suggested retail price for grinding is $0.50 per square foot. If the project were to have incurred the cost the outlay of funds would have been, $3,895.
 Figure 88. House Two at completion Click image above for a hi-res version |
 Figure 89. Backyard of House Two Click image above for a hi-res version |
Observations
- On-site grinding as a process and concept does work.
- On-site grinding on a large custom house building site is practical.
- The cost of on-site grinding at $.50 a square foot is a value proposition that needs help.
- On-site grinding of wood and drywall create a great soil amendment material for most of the areas soils, and provides a monetary offset.
- On-site grinding of asphalt shingles is a very efficient use of manpower and is a very practical application of materials that provides a monetary offset.
- On-site grinding of bricks makes a very good base material that does provide a monetary offset.
- Electing to grind the TechShield in the middle of the wood grind was a mistake.
- Not insisting upon building the entire wood mat possible and soon as possible was a mistake.
- Transferring what we learned about the grinding process to production builders would be of limited value due to the very small lot sizes they build on.
- Skilled mechanical operators are required to maximize the power and speed of the equipment.
- Wet cardboard does not grind very well.
- Packaging waste is still considerable as a function of volume in a house of this size.
- We did observe men working on rainy days on the wood mat and following rainy days on this site when they were no men working on nearby sites.
- The changes in The Woodlands Operating Companies enforcement of their deforestation policy lead to a massive amount of green waste very late in the project.
- The builder did an excellent job of sorting and storing the materials for the grinding process.
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