Transcript 1274_C_2016-06-20_08-57

Inefficiency in Building Retrofit Processes
– TES EnergyFacade Cases Evaluated
Yrsa CRONHJORT, Sebastian HERNANDEZ MAETSCHL, Wolfgang HUβ,
Frank LATTKE, Simon LE ROUX
Department of Architecture; Aalto University School of Arts, Design and Architecture; [email protected]
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
 Part of work in project
Innovative lean processes and cooperation models for planning, production and
maintenance of urban timber buildings, leanWOOD
(WoodWisdom-NET, 2014-2017, coordinator TUM)
WP4 Validation T 4.1 Learning from Practice
Partners from Germany, Finland, France and Switzerland
Coordinator Technische Universität München, TUM
Other research partners: Aalto University, FCBA Institut Technologique,
Hochschule Luzern, VTT Technical Research Centre of Finland
 The paper presents a case study of three building envelope retrofit projects realized
using large-scale timber-based elements, TES EnergyFacade
 Aim: to identify critical issues in the design and building phases as a basis for developing
solutions towards leaner timber building processes and reduced costs
 4 partners involved:
Aalto University, Gumpp & Maier, lattkearchitekten, Technische Universität München
 Follow-up studies have looked at new-built projects
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
METHODOLOGY
 Comparative case study
 Based on semi-structured interviews conducted by the main
author with the co-authors, who represent different project
stakeholders such as architect, contractor, manufacturer, and
researcher. (2014)
 Discussions took place after finishing the building works, and
did thus not interfere with the processes on site
 Also based on personal experiences as researcher of the
building retrofit processes
 Case experiences mirrored against earlier research results
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
TES EnergyFacade
Timber-based Element Systems for Improving the Energy-Efficiency of the Building Envelope
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
 TES EnergyFacade can be characterized as:
An industrialized system (Viana, Bulhões and Formoso; 2013)
Engineer-to-order (ETO) system (Viana, Bulhões and Formoso; 2013)
 TES EnergyFacade enables mass-customization by employing mass-produced elements
for customized products
 Opportunities provided by systems supporting mass-customization (Bildsten; 2011):
(1) The knowledge of costs, (2) reduced lead-times, (3) a secured availability of
materials, (4) a reduced risk of production failures, (5) improved quality.
 Identified barriers for systems supporting mass-customization (Bildsten; 2011):
(1) Tolerances, (2) the cost of development, (3) the acceptance of the system by clients,
(4) price, (5) supplier dominance.
 Prefabrication could enhance the efficiency of building refurbishment processes
(Kemmer and Koskela, 2012)
 Challenges: (1) costs and budget, (2) the involvement of stakeholders like tenants, but
also managers, (3) changes in works, (4) risks related to uncertainties, (5) excessive
detailing in planning stages. (Kemmer and Koskela; 2012)
 Call for case projects testing lean management practices including prefabrication or
standardization (Kemmer and Koskela; 2012), and suggest an increased quality,
reductions in cost and time as expected benefits. (Kemmer, Koskela and Nykänen; 2013)
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
Case A, Finland Case B, Germany
Case C, United Kingdom
Year of
construction
Year of retrofit
Building type
1985
1966
1974
2012-2013
Student housing
Height
Load-bearing
frame
Client
2-storey
Concrete elements
2011-2013
Residential apartment
building, social housing
6-storey
Brick and concrete
2013-2014
Residential apartment
building, social housing
4+1 storeys
Concrete elements
Student housing
foundation
Construction company
Local housing association
/ the city
Task-based contracted,
architect as coordinator
Local housing association
Design and Build;
client and main
contractor
Task-based contracted;
client and planners,
construction companies
Design and Build;
client and main
contractor
Main
contractor
Contract type;
partners
Timber manufacturing
and building company
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
A Design and Build contract
illustrated by the Finnish
case. Some specialist
contracts were awarded due
to the pilot building nature.
Image: Simon le Roux
The German contract model
with the architect as main
developer and coordinator of
the project.
Image: Frank Lattke, based on
graphical design by Sonja Geier
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
 Design responsibilities
In Finland and the UK the architect was responsible for the initial design only,
the main contractor coordinated the project
In Germany the architect was contracted for the whole duration of the project
including site supervision and handover of the building. The architect acted as
the principal designer and main coordinator, including detail designs suggested
by other planners or building parts manufacturers.
Timber-building specialist/structural engineer was involved in Germany and the
UK, but not in Finland
 Project budget
In Finland capped to the price of new-built
In Germany and the UK , the pricing based on previous experience, general
building costs, and a result of negotiation
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
FINDINGS
 Costs: the use of prefabricated timber-based elements might have increased the price in
comparison to state-of-the-art solutions due to risk pricing, as a timber project requires earlier
experience of building with wood. It is also generally difficult to manage risks in building
refurbishments.
 The Design and Build model with a fixed lump sum did provide cost safety for the client. However,
it led to a sub-optimization of costs, which had negative implications on the overall control.
 The use of prefabrication and the context of refurbishment caused pressure on design. Technical
solutions are constrained by the existing construction and require deep expertise. Therefore, an
early involvement of specialist designers would allow for an early detection of technical limitations,
and improves the coordination of different measures.
 Discussed cases highlight the importance of coordination. In the UK and Finland the builder-driven
approach led to on-site adaptations, whereas in the German case, an early established project
design team assured a designer controlled overview of deliverables.
For example: In the UK design liability was shifted forward in a chain from the client to the contractor
and then to specialists or subcontractors. A late subcontracting of separated building works created a
risk of deficient interfaces between trades, design conflicts and liability gaps. Sources of inefficiency
included redesign, rework, delays, order of work and quality control. The challenges are identical with
earlier reports on building refurbishment processes, regardless of the use of prefabricated components.
 Based on this study, the level of building regulations and building surveillance by public authorities
also varies or is unregulated in building refurbishment projects. This is changing with, for example,
new Finnish regulations regarding buildings undergoing major renovations.
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
CONCLUSIONS
 This paper presented three refurbishments including building envelope retrofits using TES
EnergyFacade prefabricated timber-based elements.
 The cases were carried out based on a Design and Build model in Finland and the UK, and an
architect driven process in Germany.
 Literature suggests prefabrication as a mean to improve building refurbishment processes, and
leading to increased quality, reduced costs and time. However, it is recognized that all-inclusive
solutions might lead to increased costs.
 This study did not confirm expected benefits. The three cases revealed that the estimation of
costs is a barrier for entering the construction business with new solutions like TES EnergyFacade.
Additionally, the cases revealed inefficiency in the project delivery process, like delays caused by
design conflicts. Value was also compromised for the end-user. The end-user was either removed
or ignored in two out of three cases.
 Building projects in general and refurbishment projects specifically are becoming more complex.
Hence the need for different competences and the risk for incompatible designs increases. Based
on this study, prefabrication alone does not solve the equation.
 Process development and the introduction of more closely integrated project design teams, and
improved coordination could allow for an increased use of accumulated know-how and reduce
inefficiency in the project delivery process.
Inefficiency in Building Retrofit Processes –
TES EnergyFacade Cases Evaluated
Yrsa Cronhjort
Architect, Project Researcher
[email protected]
 +358 50 566 0802
leanWOOD
Project of WoodWisdom-Net 4th Joint Call 2013
www.holz.ar.tum.de/leanwood/about-leanwood/
Image by Technische Universität München