All of the structures had additions, and these were typically for; 1) adding enclosed living space, 2) adding kitchen and bathroom facilities on older structures, 3) enclosing an existing open porch area. Four (4) out of six (6) could be made habitable, and three (3) of six (6) had been recently occupied prior to the building’s removal. One (1) house had been occupied by homeless persons without heating, kitchen, or bathroom facilities. Three (3) of the six (6) structures were found to have asbestos containing materials (ACM) requiring abatement. Two  (2) of the structures contained only non-friable asbestos which could have been “wet demolished” by mechanical means but would have required the entire demolition wastes load to be disposed off in a hazardous materials landfill. Only one building had LBP only on the inside, typically LBP was found on exterior window and door trim, where it was used in gloss and semi-gloss paint for durability.

 

Two (2) of the six (6) buildings were on property slated for immediate commercial or multi-family redevelopment, two (2) were on property slated for long-term redevelopment, and two (2) buildings were on land not slated for redevelopment. The latter two (2) structures may have been left vacant for an indeterminate length of time if they had not been used for this project. During the course of the project, one building verbally committed to the deconstruction project, on a site slated for commercial redevelopment, was demolished. In addition, two candidate buildings, on sites slated for redevelopment, were moved. One structure that was considered for the project was considered too dilapidated for a reasonable deconstruction and another was passed over due to scheduling conflicts and was subsequently partially renovated by the owner. The average size of the six structures was 1,476 SF.

 

Based upon literature review and anecdotal information, this sample of structures would appear to be representative of residential demolitions in the United States. Also, approximately 94% of all residential buildings built each year in the US are light wood-framed construction (NAHB, 1994).

 

Data Collection

On-site labor was documented by recording each worker’s activities on a 15-minute time increment.  There have been several well-documented deconstruction pilot projects in the US with this detail of data collection, most notably the Fort Ord Pilot Deconstruction project conducted by the Fort Ord Reuse Authority  (Cook, 1997) and the Riverdale Pilot Deconstruction Project conducted by the National Association of Home Builders Research Center  (NAHBRC, 1997). These projects provided models for creating the data collection process. Data is divided into two categories; the deconstruction of the structure and the processing of the salvaged materials. The cost of a traditional demolition was calculated for each structure, including disposal costs. Salvage revenues were estimated using a percentage (25-50%) of retail prices from local building materials suppliers and the experience of a former used building materials store owner/operator in Gainesville, Florida. Disposal costs were estimated by weight and costs data provided by the wastes haulers for the project.

Worker labor activities were sub-divided into categories by the location in, or component of, the building in order to calculate the costs of deconstructing a particular component of the building, and the costs to salvage a unit of a particular material. The latter information was used to assign a unit cost of extraction and processing that could be compared to the pricing units for materials, i.e. number, linear feet, or board foot of material. Labor productivity data was collected in the following task categories:

(S) upervision 

Directing and planning the flow of work on the job site.

(Decon) struction

Labor involved in the initial removal of materials from the structure. Any manual or mechanical procedure required to remove materials for salvage, either the direct handling of a material or removing other materials to gain aPCCEss to the salvage material.

(Demo) lition

The hand or mechanical removal of building materials for direct disposal.

(P) rocessing

Preparing materials for redistribution in reusable form.  Denailing is the most typical processing activity.

(N) on-production

No work is being performed. Includes breaks and the unloading and clean-up of daily tools, but excludes lunch.

(C) lean-up / (Dis) posal

Sweeping and/or removing debris or demolition materials from a work area and/or disposal into a roll-off container. 

L) oading/unloading

Loading or unloading materials from the site onto a truck for transport and at the final storage area.

The largest percentage of time on any deconstruction was the deconstruction activity, an average of 26% of total time. The next greatest percentage of time was spent in processing materials at an average of 21%.  Disposal and cleaning required an average of 17% of total time. Demolition required an average of ~12% of total time. The house with the largest percentage of time spent for deconstruction was the house at 901 SR 301 (47.8%). This house was being removed for redevelopment and had a very short time frame for the deconstruction. It was also located on a major highway in the corner of a shopping center site, and materials were redistributed by placing them neatly in separate piles at the site and posting “Free Materials” signs to encourage passersby to remove the materials themselves. All of the materials were removed within one day after the completion of the deconstruction.

 

Table Two - Sample Data Sheet

Location:				Completed by:			Date:
Worker	#1	#2	#3	#4	#5	#6	#7
7:30
Activity
Room
Location
Material
Activity	Supervise	Decon	Process	Demo
	S	Dec	P	Dem
	Clean/Disposal		Non-Prod	Load
	C/Dis		N	L