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Reuse of building components: an economic analysis
Frédéric Bougrain
1and Sylvain Laurenceau
21
Department of Economic Studies, CSTB, Université Paris-Est, Champs-sur-Marne, France
2Environment and Energy Direction, CSTB, Université Paris-Est, Champs-sur-Marne, France
Abstract
In France the building industry accounts for the largest share of greenhouse gas emissions. It
represents about one quarter of France’s national emissions. To deal with this challenge, the
French energy transition for Green Growth law was adopted in July 2015. Buildings
renovation, clean transport, renewable energy and the circular economy are at the agenda.
The law sets several ambitious objectives for construction and demolition wastes (C&DW).
The goal is to recycle 70% of construction and engineering waste by 2020 while around 60%
of construction and demolition wastes (C&DW) are currently reused, recycled or recovered.
Reuse of components is currently undisclosed but represents an opportunity to fully take
advantage of wastes potential. Moreover, it brings environmental and economic benefits for
future constructions and local territories.
This paper focuses on the economic benefits of reuse. The aim is to examine whether a
demolition project promoting the reuse of demolition wastes offers value for money in
comparison with a demolition project that does business as usual.
After a literature survey, an in depth evaluation of costs and labour impacts is proposed for a
case concerning bricks for a small arena. Results show that reuse can bring direct economic
benefits if the demolition process is based on the same tools as a traditional demolition.
Moreover it would have a positive impact both in terms of direct costs and local employment
if the process is optimised. Deconstruction is still in its infancy and the value-added chain is
not well developed. Thus, the learning curve is important.
This paper is produced within the REPAR 2 project, cofounded by the Agency for the
Environment and Energy Management.
Keywords:
reuse, economic analysis, deconstruction, local economic impact.
Introduction
To mitigate climate change, most European countries have decided to reduce greenhouse gas
emissions by a factor of 4 before 2050. In France the building industry accounts for the
largest share of greenhouse gas emissions. It represents about one quarter of France’s national
emissions. To deal with this challenge, the French energy transition for Green Growth law
was adopted in July 2015. Buildings renovation, clean transport, renewable energy and the
circular economy are at the agenda. The law aims at tackling waste and promoting the
circular economy. It set several ambitious objectives for construction and demolition wastes
(C&DW). The goal is to recycle 70% of construction and engineering waste by 2020 while
around 60% of construction and demolition wastes (C&DW) are currently reused, recycled or
recovered.
Among the “3Rs” (reuse, recycle and reduction), reuse of components represents an
opportunity to fully take advantage of wastes potential.
This paper focuses on the economic benefits of reuse. After a literature survey, an in depth
evaluation of costs and labour impacts is proposed for a case concerning bricks for a small
arena. The aim of the comparative analysis is to test whether a demolition project promoting
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the reuse of demolition wastes offers value for money in comparison with a demolition
project that does business as usual.
The economic advantage of deconstruction: a literature review
Disassembly, demolition and deconstruction concern the end-of-life phase of a building and
are frequently source of confusion while they refer to distinct actions:
•
Disassembly means “taking apart components without damaging, but not necessarily
to reuse them”;
•
Demolition is “a term for both the name of the industry and a process of intentional
destruction”;
•
Deconstruction is “similar to disassembly but with thoughts towards reusing the
components” (McGrath and al., 2000).
The literature provides several reasons to explain why demolition is still dominant and
prevails over deconstruction:
•
Most buildings are not designed and built to be deconstructed;
•
Clients may be reluctant to reuse materials when there are no certification schemes
proving that the employment of second-hand materials and components does not
jeopardise the quality of the new building;
•
The lack of detailed information about the materials and components employed in a
building may affect the economic feasibility of a deconstruction project. This issue
reinforces the need for a careful pre-deconstruction survey;
•
Demolition is a niche and most contractors prefer to make comfortable margin and to
do business as usual;
•
Deconstruction is still in its infancy and the value-added chain is not well developed.
There is a lack of guidelines for architects (to create a building that is easier to
deconstruct) and contractors (to improve the efficiency of the disassembly process).
This lack of experience limits the benefits associated with this approach.
Despite these barriers, deconstruction can be a valuable solution since it offers social,
economic and environmental benefits:
•
Social benefits: demolition is mainly based on mechanical equipment used to bring
down buildings while deconstruction is more labour intensive. As such, it offers
employment opportunities. Deconstruction and the resale of recovered materials is a
source of business. It can provide employment to local communities in search of
economic revitalisation (Penn and al., 2003).
•
Economic benefits: several examples indicate that sales of materials and components
strongly reduce deconstruction costs. The deconstruction of six downtown buildings
in Wisconsin saved approximately $37,000 (Newenhouse and Fuller, 2003). This is
mainly due to the avoided landfill costs. Since the amount of materials disposed in
landfills is reduced, it has positive environmental impacts. Similar results were found
by Storey and Pedersen (2003) in New-Zealand. Around large cities such as
Auckland and Christchurch, tenders were offered at a price lower than the cost of
demolition. It was offset by the selling of the salvaged materials and the avoidance of
landfill costs. However, costs can also exceed benefits.
According to Eklund and al. (2003) who analysed two projects, “using a large degree
of reused concrete elements cost roughly 10% to 15% more than building with
conventional building practice”. Moreover, it creates financial uncertainty around the
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project. They also mentioned the lack of experience of most stakeholders. For
example, the contractors who were surveyed indicated that with more experience and
by developing technology and building techniques for use with reused materials, the
same job could be done with a 10% to 15% cost reduction.
•
Environmental benefits: Deconstruction improves the effective sorting of C&DW. It
improves the identification of materials and potential contaminants, the separation of
materials that are valuable such as glass, metals, concrete, etc. Thus, it positively
impacts reuse and recycling rates.
However, the economic benefits of reuse and recycling appear strongly dependant on local
conditions:
1.
There is a need to find projects with recovered materials, demands for this type of
resources and established businesses that can do the deconstruction;
2.
Size of sites matters. Manoeuvrability is more limited for small sites. Thus,
productivity is affected. It is also more difficult to store materials on small sites.
Urban sites have probably more resources but they are more constrained by their size
than sites away from densely populated area.
3.
Distance between the construction site and the C&DW treatment installation strongly
impacts the profitability According to Lassandro (2003), transport costs can affect the
demolition costs by 40%.
All these issues are presented in the following case.
Case study: Reuse of bricks
1. The steps from deconstruction to reuse
The case involves an arena made of bricks. The building site was 5 km away from the
deconstruction site consisting of an old factory located in La Courneuve, a city in the suburbs
of Paris. About 5,000 m² were deconstructed but only a small percentage of bricks were
reused. The study examines the different stages of the deconstruction project and details the
data used for the analysis:
•
Pre-deconstruction survey: it was done by Bellastock a local association specialised
in deconstruction. Two types of bricks with different qualities were identified.
Mechanical equipment used for demolition was not considered as adapted to preserve
these secondary materials. The diagnosis proposed to screen the bricks before sorting
them on the deconstruction site.
•
Sorting: the bricks were collected and taken for sorting, before being transported to
the building site. A sifter was used for one day to treat 450 m
3of bricks. Only 16,400
(33%) were recovered. With a manual approach a higher quantity of secondary
materials would have been preserved.
•
Evacuation: Costs of transport of C&DW to remote backfilling sites and recycling
platforms were avoided. Trucks had only to drive for 5 km instead of 40. Three
round-trip rides were necessary.
•
Storage: it was done on a site owned by the client.
•
Transformation of materials: This activity consists in manual sorting, restoration of
the bricks and quality control. It is carried out on the construction site. This step was
performed as part of a school project by 12 low-skilled workers in integration. They
were supervised by one person employed by Bellastock. For this phase of manual
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sorting which lasted 17 days, some mechanical equipment was rented for 5 days to
facilitate the handling of the bricks.
•
Purchases of new materials: the cost for a new brick is €0.68 and the brickyard is
located 60 kilometers away from the construction site.
2. The financial analysis
Six main cost categories were considered for the analysis:
1.
Transportation costs were calculated according to driving hours, distances between
deconstruction site and worksite / recycling platform;
2.
Labour costs consist of deconstruction activities, supervision work and training of the
low-skilled workers;
3.
Pre-diagnosis costs refer to surveys done before the deconstruction in order to
appreciate the potential of the old buildings;
4.
Mechanical equipment costs consist of renting machines for sorting bricks;
5.
Material costs relate to the purchase of new bricks;
6.
Disposal costs.
Cost of reused bricks: €1.41/brick – cost of new brick: €0.90/brick
Figure 1. Secondary materials versus new materials
3. Social analysis
Deconstruction is more labour intensive and it entails greater labour costs. However, it also
has a greater social value since it contributes to the training and employment of low-skilled
workers (table 1).
Table 1. Working days: deconstruction and reuse versus demolition and purchase (for 10 000 bricks)
Deconstruction and reuse of bricks Demolition and purchase of new bricks
Working days Working days
Pre-deconstruction survey
0.1 Transportation of old bricks (to recycling
platforms)
0.1
Mechanical sorting 0.2 Disposal costs 0.6
Supervising, training, restoration and quality
control 210,4 Manufacturing process 5 Transportation of new bricks 2.3 Total 211 Total 8 8% 15,50% 47% 29,50% Mechanical sorting Mechanical equipment 75% 18% 6% 1%
Purchase
of new
materials
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4. Sensitivity analysis
Deconstruction is still in its infancy and the value-added chain is not well developed. The
learning curve is important. Thus, it is appropriate to look how productivity improvement in
manual sorting and restoration would impact the economic results. Several hypotheses, set
with different contractors and based on feedbacks, were retained:
•
Manual sorting and restoration time is reduced by 30%;
•
Mechanical equipment are better used and renting time is reduced by 30%;
•
Supervising time is divided by two (the case is a school project and more time is
dedicated to supervision than in traditional projects).
Table 2. Socio-economic analysis integrating productivity improvement due to experience Deconstruction and reuse of
bricks
Demolition and purchase of new bricks
Cost for one brick € 0.79 € 0.90
Working days (10,000 bricks)
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