R-Bau - Development of a replicable deconstruction strategy for residential buildings to force the recovery-oriented dismantling

Starting point / Motivation

By the end of 2015, the recycling-oriented deconstruction of the buildings did not play an important role in demolition and renovation activities. The demolition of buildings is mostly tendered and billed at flat rates; the cost of depositing of the resulting waste material (primarily rubble) is often very high. There are often enormous saving potentials regarding costs and resources in the deposited waste of construction material that have not been neither considered nor calculated. According to the EU "Waste Framework Directive" (WFD) 2008/98/EG the demolished construction elements should mainly be reused, recycled and only disposed, if the recycling is not possible. In Austria, the implementation of this Directive has been mainly through new decree for "Recycling of Building Materials", which came to force on 1st of January 2016th.

Contents and Objectives

Contents of the project "R-Bau" is developing a replicable deconstruction / dismantling strategy in order to promote the recycling-oriented demolition in cooperation with relevant stakeholders. This is a substantial contribution for establishing the recycling-oriented demolition in residential building sector as state of the art.

Methodical Approach

In a first step, the deconstruction / demolition processes and their sub-processes were analysed in terms of juridical, technical and economic conditions. These sub-processes included planning, tendering and procurement, implementation and waste management tasks.

Based on these processes, the next step was to identify, categorize and evaluate building elements or materials, which could be suitable for reuse or recycling. For this purpose, standardized building models were developed, in order to evaluate the dismantling capability of building materials and elements from demolition to reuse by suitable software tools technically, economically, environmentally and energetically.

Finally, the insights gained were used for the creation of a dismantling / demolition catalogue, which contains in addition to a checklist, instructions and templates for tendering for demolition, recommendations for removal and reuse of the building elements and components in the new building.

In the course of these findings, together with relevant stakeholders (mainly housing developers, waste managers, constructors, and facility managers) a replicable implementation strategy was developed, in order to accelerate the implementation of the recycling-oriented dismantling and demolishing in the construction sector in Austria.

Results

The analysis of the current demolition process in this project in terms of legal, technical and economic conditions shows that the concept of integrative planning, tendering / procurement, construction and waste management in demolition activities in Austria is not state of the art (as of December 2015). Usually the tendering and procurement are through lump sum contracts. The optimization measure considers the promotion of an inclusive planning, tendering and execution of demolition activities.

The simulations of the recycling-oriented dismantling and demolishing building models with specific materials and components show that the components used in various construction periods, effect deconstruction and disposal differently. Therefore, the buildings cannot be seen as homogeneous demolishing objects, but as a composition of a group of components, which can vary historically and by various refurbishment measures implemented during the lifetime of the building. The model calculations prove that the cost of deconstruction and disposal of construction waste relates to increased material and component diversity in more modern buildings in general. This diversity not only affects the deconstruction costs, but also the environment and the (energy) resources. Thus, it will be necessary in the future, to determine the optimal concept for destruction and demolition from a more holistic view, depending on the material composition and function of the installed components of the buildings.

Regarding the implementation of a recycling-oriented deconstruction in future buildings, following recommendations are derived:

• Sustainable use of natural resources (EU Construction Products Regulation, CPR Regulation No. 305/2011)
• Implementation of integral planning and execution
• Compliance with the cost effective principle
• Sustainable tendering process / procurement
• Sustainability as part of corporate strategy

On the Meta level, this aims at bringing recycled construction materials to the market (creating supply). On the other hand, targeted measures (sustainable planning, tendering and business orientation) support creating demand (creating market for supply and demand). Further details are described in the publicly available deconstruction catalogue.

Prospects / Suggestions for future research

To establish the sustainable and practical recycling-oriented demolition and deconstruction in Austria, the following measures must be implemented in the future:

• Market stimulation by the legislation (e.g., through optimization of existing and creation of new regulatory measures, development of financial incentives)
• Further development and promotion of information and training sessions
• Implementation of pilot projects
• Creation of a market for secondary construction and raw materials
• Development of tools for the efficient and effective handling of specific issues

Implementation of these measures contributes relevantly in adaptation of terms and conditions in the "Sustainability in construction and deconstruction". This helps developing a resource management frame at company or regional level. Subsequently, several businesses / communities / regions with functioning resource management systems establish the foundation for a recycling-oriented dismantling and deconstruction at national level. In the publicly available implementation strategy, further details are described.