XV International Cost Engineering Congress in Rotterdam, April 20-22, 1998



A structured approach to  the planning of maintenance and

refurbishment: ‘DUEGA’ an example of applied research



By:                 Martin Wright, Chartered Surveyor ARICS, Bauökonom AEC

·        Responsible for the management of the DUEGA Research Project

·        Director of the Cost Planning Department of PBK AG

·        Member of the Central Committee of the Swiss Association for Construction Economics and of the Chamber of Professional Associates

·        Member of the Swiss Delegation to the CEEC



Address:      PBK AG Projektmanagement, Bauadministration, Kostenplanung

                        Joweid Zentrum 1

                        CH-8630 Rüti / Zürich



E-mail:           wright@pbk-ag.ch

Telephone:  +(0)55-250 33 80

Fax:               +(0)55-250 33 81



The Project


The Swiss research project DUEGA (Diagnosemethode für die Unterhalts- und Erneuerungsplanung verschiedener Gebäudearten) provides a systematic basis for condition assessment surveys and the planning of maintenance and renewal measures for all types of buildings. The project was, from the beginning, concerned with applied research, i.e. putting existing material to a practical use.


Traditional approaches involve unstructured, uncoordinated data collected by government departments, independent planners, representatives of the Client, contractors, estate agents and the like, who are commonly unaware of existing information. It is plainly inefficient to waste scarce resources repeating work which has already been carried out by someone else, when the time could be used for finding better solutions.


DUEGA co-ordinates both existing concepts and the results of previous research and development into a structured system which allows data to be reused on a multi-disciplinary basis.


Public funding was limited to an amount equal to that which could be raised from private sources. These sources (figure 1) were not only private companies, but included various professional bodies, with the clear intention of establishing a standard system with wide support.


        Figure 1: Project organisation and funding



The concept


Emphasis was placed on the development of a standard system and not on producing a computer program. The standard structures developed can be processed with existing software, but also provide a basis for new developments by professional software companies, with the aim that competition will lead to innovative solutions.


The method developed was aimed for use at differing phases and differing levels of detail within the planning and execution of works. Requirements vary according to the parties concerned and the point of time during the life of a building. Using a structured system it is possible to provide differing levels of detail, within the same overall system. This enables analysis to take place both at portfolio level and for individual buildings as well as at management and operational level (figure 2).


 Figure 2 Differing levels of analysis


       In Switzerland we have extensive data bases for cost planning on an elemental basis. DUEGA is based on the existing standard elements and regroups these into what have been termed 'macro elements'. These are used for the preliminary stage of condition assessment and can be further detailed using existing cost-planning structures and systems - we were careful not to waste time reinventing the wheel.


 Figure 3 connection to existing data bases


The top-down principle forms a central theme within the DUEGA system, allowing detailed data to be summarised for management decisions as well as permitting an efficient approach when dealing with specific projects. An initial assessment takes place at the uppermost level and only cost relevant items are further detailed (see figure 4).


 Figure 4 Top down approach


Simulation of the practical effects of the number and size of items and the probable resulting accuracy formed an important part of the project. The results, based on figures from the analysis of actual projects, a 90% probability and various scenarios as to standard deviation at each level confirmed this approach (figure 5)




















Figure 5 Typical results of simulation of accuracy


Data Classification


The DUEGA system incorporates several standard classifications:

·        The cost classification

·        The condition classification

·        The classification of renewal measures

·        The classification of building types


The cost classification bases on the standard Swiss elements as set out in the Swiss Standard Form of Cost Analysis [SN 506 502]. The elements are very similar to many other classifications such as in Germany [DIN276], the CEEC [Concordance document], Austria [Ö-NORM B 1801-1], the United Kingdom [BCIS], and northern Europe [SfB]. This enables comparisons across national boundaries (figure 6).

 figure 6 Typical elemental classifications


DUEGA was restricted to building work, but the Swiss elemental classification covers building and civil engineering, which would permit easy extension of the method to civil engineering projects.


The standard elements are regrouped into renewal orientated so called 'macro elements' and subdivided into sub-elements (figure 7).


     figure 7 three levels of cost classification


The codes for assessment of the condition and the renewal measure are limited to four and five categories respectively to allow simple classification and data retrieval (figure 8)


 Figure 8 classification of condition and renewal measures


The classification by building use was directly taken from the CRB Swiss Database [BKK-Katalog] published by the Swiss Research Centre for Building Rationalisation [CRB] and is a two level coding similar to various international classifications (see figure 9)

















Figure 9 Classification of building types



practical procedure


The DUEGA approach differs from traditional Swiss procedure, where Architects or Engineers tend to present Clients with one solution for the refurbishment of a particular property. With DUEGA various scenarios can be produced for the refurbishment and the planned maintenance over the life cycle of the building (figure 10).


 Figure 10 practical procedure


Interestingly this concept was also taken up by the University in Karlsruhe, where another research project [OGIP/DATO ] concerning evaluation of energy and toxic balances during the planning of buildings. The classification used in Karlsruhe again bases on the Swiss elements and the appropriate figures can be included in the information for the different scenarios.

Planning of maintenance depends on accurate and reliable data on the size and condition of existing structures. The starting point must therefore be to collect this data. The detail required depends upon the aim of the investigation. In all cases care should be taken to proceed in stages, starting with the information at level 1 of the cost classification and only going further where the results of the investigation will be affected by additional details.  


The assessment of a property starts with a visit to the site and the noting of the most important data, starting with the macro-elements. These provide an overview and indicate which elements must be further detailed. This prevents going through detailed checklists for items where this can be  excluded from the initial inspection. Data can be input conventionally into paper check-lists or directly input into a palm top computer.


figure 11 Excerpts from data collected


Once the data has been collected on site, it can be further processed in the office and linked to libraries of standard descriptions and price data bases to provide reports and estimates of the overall order of the refurbishment costs. Also, cost relevant items can be identified, where it may be necessary to make further inspections by specialists and the appropriate additional assessments initiated


Each macro-element (or its subsequent sub-division) is assessed on various factors:

·      size (eg. the area of window)

·      the location (eg. south elevation)

·      the condition, based on a scale from a (good condition) to d (end of life cycle)

·      the refurbishment measures foreseen, based on a scale from 0 (no measures foreseen) to 4 (replacement)


In the ensuing planning phase further sub-division of the individual quantities is necessary according to various criteria such as the execution date (for planned maintenance), the project section, the priority, the cost code, the responsible planner, etc. (figure 12)

 Figure 12 sub division of quantities


With the codes and descriptions of the condition and measures foreseen it is possible to link directly to databases with comparative data (figure 13). The classification by elements allows direct queries on the Swiss databases

 Figure 13 calculation and queries on comparative data




In Switzerland we have two standard databases on construction cost on an elemental basis:

·        one with with historic data from actual projects, i.e. feed back [BKK-Katalog] (figure 13)

·        and one with composite items synthetically built up, i.e. feed forward [BEK-Katalog] (figure 14)

 Figure 14 Composite item and build-up


Both of these databases are predominantly new-build orientated, but the BEK-Katalog is gradually being enlarged to incorporate more renewal work. The BKK-Katalog could easily be extended to include analyses of refurbishment projects.


The DUEGA project included the analysis of 8 completed projects in order to highlight any problems , but also to demonstrate the method of analysis and to provide some, albeit limited, data for inclusion in an extended BKK-Katalog. The projects analysed were deliberately chosen from differing building types and with differing scopes of work (figure 15)


 Figure 15 projects analysed


In order to simplify classification and to assist in the compilation of descriptions, standard text conserves were produced for all macro-elements and the most important elements and sub-elements. The texts are structured identically to the Swiss standard library of descriptions for bills of quantities [Normpositionen-Katalog NPK], which allows processing of texts to a locally recognised standard procedure. Separate catalogues were produced for condition assessment and renewal measures.


A CD-ROM was also produced with the final report of DUEGA together with the Project analyses, the Simulation Calculations, Checklists with typical descriptions for Condition and Measures and a set of spread sheets for condition assessment and cost estimates for simple buildings.




The future


Care was taken during the research project to maintain close contact with the Swiss Research Centre for Building Rationalisation CRB, the most important publisher of documentation in Switzerland and also to integrate professional organisations. The intention being, that after completion of the research project DUEGA, the method developed would actually be put into practice on a wide scale and not just disappear onto some library shelf!


This has shown positive results and CRB is now running a test phase with selected practitioners (Construction Economists, Architects, Property Managers and Professional Clients), before embarking on the official release of DUEGA as a commercial project (foreseen for the middle of this year). Parallel to the test phase, software firms are being lobbied and supported to ensure that several versions of the necessary instruments are available to practitioners. We thus hope to achieve a positive transition from a research project and contribute to the efforts of Clients and Planners with the ever increasing amount of refurbishment on the vast existing stock of buildings and civil engineering.





Building Cost Information Service, Great George Street, London WC2


Berechnungselement-Katalog, published by CRB


Baukostenkennwert-Katalog, published by CRB

Concordance Document CEEC

European Committee of Construction Economists CEEC



Swiss Centre for Building Rationalisation, Zentralstrasse 173, CH-8003 Zürich


Kosten im Hochbau


Normpositionen-Katalog published by CRB


Optimierung von Gesamtenergieverbrauch, Umweltbelastung und Baukosten, ifib Universität Karlsruhe (TH), April 1996

Ö-NORM B 1801-1

Kosten im Hoch- und Tiefbau


SfB Bureau, S -11184 Stockholm

SN 506 502

Elementkostengliederung EKG, published by CRB