A large quantity of waste is generated during the production of building
components and after the building demolition. Construction and demolition
activities in Europe are responsible for 40 - 50% of solid waste production
which was estimated over 460 million tonnes per year in EU-27 (about 1.1
tonnes per person per year) excluding excavations. It contains mostly minerals
from the structures.
The construction sector also consumes about half of all natural resources
extracted in Europe yearly, that have very high energy demands on their
transformation into building products. It has been estimated that 40 - 50% of
all extracted raw materials are transformed into building products. The
construction sector uses vast amounts of energy in the first three stages of
the production process: resource generation, resource extraction and
intermediate product manufacture.
Therefore the focus of today’s environmental policy is on the building
end-of-life scenarios and material efficiency. Recycling and material re-use
becomes the common practice, but it is not always environmentally efficient,
and material separation of composite structures is very challenging. Building
elements have often longer service life than the building itself and are,
therefore, suitable for recovery and re-use after deconstruction. However,
component re-use is still not widespread practice because of technological and
institutional barriers. Structural components are not usually designed to be
re-used, even though they are designed for deconstruction in some cases.
Recycling and material re-use is the common practice nowadays, but it is not
always environmentally efficient, and material separation becomes more
challenging in case of composite structures. Building elements have often
longer service life than the building itself and are, therefore, suitable for
recovery and re-use after deconstruction. However, component re-use is still
not widespread practice because of technological and institutional barriers.
Structural components are not usually designed to be re-used, even though they
are designed for deconstruction in some cases. The main barriers for re-using
are (a) long service life of building products, (b) their spatially fixed
nature, and (c) discrepancy between building owners and users.
Sustainability
Reusing of building components has impact on all aspects of sustainability of
the built environment.
The business perspective emphasizes the possibility to increase the “green”
image of the product, reducing the waste charges, challenging the growing need
for housing removal, developing new competences and work possibilities, and
application of smart and modular building systems.
The ecological perspective impact will be in reduced waste generation and
natural resources consumption that can reflect in higher eco-labelling
(BREEAM, LEED, …).
The social perspective challenges the migration to urban centres, the values
and living environment change, and new legislation.
Key roles in re-use process
Designers - Designers have one of the most important roles in
structural elements re-use. Their documentation, drawings and instructions
significantly affects the effort needed at the building deconstruction. Not
only selected components and technologies are important, but also the way how
the final design documentation availability will be secured for the whole
building’s life span. The maximization of environmental, cultural and
financial value at the end of building’s life should be considered already in
the design stage. Designers have to get access to the information about the
actual and potential reclaimed components supply, sizes and material grades
and they need to be flexible to adapt to current situation.
Owners and investors - Re-use project can be successful only when it is
fully supported by the building owner or investor. Therefore the building
owners and investors are equally important as the designers. They need to
understand the process and its advantages and drawbacks. Education and
demonstration of successful cases should be the way to increase building
owners and investors’ motivation.
Raw materials - The increasing demand for building materials is
creating great pressure on natural resources. Moreover, the raw materials are
becoming scarce and more expensive. Material extractors will have to adapt to
this change in order to avoid reducing their operations and profitability.
Material producers (mills) – The production process vary with the
material. Raw material and in most cases also recovered waste (e.g. steel
scrap) is utilized to produce new building material that is sold to the
service centres or fabricators directly.
Service centres - Service centres are businesses that inventory and
distribute materials for industrial customers and perform first-stage
processing. They act as intermediaries between the producers and the
fabricators, and other end users.
Fabricators and erectors - Fabricators purchase materials from service
centres or directly from producers and fabricate the individual components
that are needed to assemble a building. Some fabricators also have their own
erection crews to assemble the components at the building site. Others
subcontract the erection to independent organisations. Fabricators may send
any waste and offcuts back to mills for recycling, usually through a dealer.
Some of the fabricators will occasionally dismantle old structures and
re-fabricate the reclaimed elements for new uses. A minority may have a small
stock of building parts that has been reclaimed waiting for appropriate new
uses.
Buildings – The way how buildings can be assembled to maximize the
usefulness and value of components at the end of a buildings life needs to be
clearly demonstrated to the construction industry. The growing number of
projects successfully shows how components from an old building or structure
can be re-used in a new building reducing the environmental impact, but the
communication of such successful cases to the construction practitioners is
not sufficient at the moment.
Demolition – Current building removal practices predominantly mean a
process of destructive demolition by heavy machinery. There is a perception
that manual extracting of building elements from buildings for re-use leads to
additional problems and costs. However, even separation of re-usable
components from the demolition waste may lead to significant recovery amounts.
Disassembly - The re-use of components can be maximized only when
careful disassembly is carried out. Many projects have shown that disassembly
is possi-ble and should be considered. The volume of disassembled building
components will increase as the demand for them increases.
Salvage yards - Salvage yards store building elements for re-use and
recycling. A few salvage yards will extract components when they recognise
potential for re-use.
Material dealers - Dealers sell waste materials for recycling and
re-use. Material is sorted, graded, batch, and sold back to producers for
recycling. These organisations will also often buy waste materials arising
during fabrication and from other sources. Material dealers will often try to
sell reclaimed material directly from the demolition site.
Design codes - The benefits of re-use can be greatly improved if
building codes emphasize the environmental aspects of the construction and
give designers more opportunities for material sourcing. The immediate goal
should be to enable structural elements re-use by establishing clear rules for
the material grading and safety of structures designed from reclaimed
components.
Design tools – The rapidly developing area of design software is
currently able to offer many useful tools for the environmental optimization
of buildings. As the buildings components are physically re-used, they can be
re-used also digitally. The implementation of building information models
(BIM) is essential to manage smooth transfer of building elements between two
different projects.
