Methodology for Proactive Maintenance of Current Buildings

Abstract

Proactive maintenance is an increasingly decisive element in rational management of buildings and in reducing global expenses, and the only means of increasing the constructions service life, avoiding premature aging and the ruin of elements / buildings, ensuring the buildings integrated management and avoiding the physical or functional collapse of their elements.

Full text

XXX IAHS 31
World Congress on Housing
Housing Process & Product
June 23-27, 2003, Montreal, Canada
Methodology for Proactive Maintenance of Current Buildings
Inês Flores Colen and Jorge de Brito
Department of Civil Engineering & Architecture
Instituto Superior Técnico, Portugal
e-mail: inflores@netcabo.pt or jb@civil.ist.utl.pt
Key words: methodology, proactive maintenance, inspections, buildings, costs.
Abstract
Proactive maintenance is an increasingly decisive element in rational management of buildings and in
reducing global expenses, and the only means of increasing the constructions service life, avoiding
premature aging and the ruin of elements / buildings, ensuring the buildings integrated management and
avoiding the physical or functional collapse of their elements.
1 Introduction
In the last decades in Portugal buildings maintenance has been a neglected activity within the construction
process. As a matter of fact and contrary to other countries within the EU, in Portugal there is no periodic
maintenance culture, accepting it as a reasonable cost for all actors, from the tenants to the landlords as
well as the owners of single flats within a building. One of the sharpest indicators is the small investment
in buildings maintenance / rehabilitation that does not reach 10% of the global investment in the
construction sector, in contrast with the European average of around 40%.
The absence of investment in this sector, the existence of a generalist legislation (compulsory conservation
works every 8 years) which is systematically breached, and inefficient politics of dwelling acquisition /
rental have aggravated the conservation status of the buildings and the users quality of life. These aspects
have led in many cases to the dilapidation of the dwelling conditions and the safety of the buildings.
New politics of incentives tend to invert this trend, namely the programs for revitalizing the cities, the
stimulus for conservation works, new legislation concerning thermal and acoustic comfort, the recycling
of construction solutions, within a sustainability and urban and environmental requalification perspective.
In this context as future strategies it is necessary to systematise data about constructions pathology, to
lobby the various actors in the construction process, to change the present laws, to implement new politics
and incentives and to develop techno-scientific methodologies, at the diagnosis and maintenance level.

Inês Flores Colen, Jorge de Brito
In this paper the most relevant parameters of a proactive maintenance integrated methodology, in current
buildings and components, are characterized, namely: the technical aspects concerning construction
materials and solutions (degradation models, durability, service life, etc.), economy (global costs of the
solutions) and functionality (adequate use and maintenance - accessibility). The main aspects are singled
out, such as those associated with the design and promotion stage (analysis of the project elements,
available data collection, planning of the inspections and maintenance actions) and the service stage
(procedures, implementation of the inspection and maintenance actions, correction of the unexpected
anomalies, control / registration of the interventions, data post-treatment and data redirected back to the
designers).
Simultaneously, a direct connection between the methodology presented and the preparation /
implementation of the inspection and maintenance plans from the design stage on is established, including
aspects related with decision, priority, interventions periodicity and the various maintenance operations
(inspections, cleaning, local repairs / replacements and prevention treatments). These plans will allow the
precise prediction of the interventions during the predicted service life and the costs and resources
rationalization, with no excessive or unnecessary spending on replacement / repair of elements, having in
mind the continuous satisfaction of the users’ demands.
2 Proactive maintenance of buildings
Maintenance actions are here intended as the technical and economic actions aimed at recuperating the
initial performance level of the building, according to a certain requirement. Proactive maintenance
actions are performed in order to anticipate the elements’ ruin, thus satisfying the requirements. The
implementation of a proactive maintenance methodology intends to invert the present situation, by
minimizing the occurrence of untimely correction actions caused by users protests concerning elements
with high degradation levels after successive or of inadequate repairs / replacements in which deficient
materials and techniques are chosen and applied [1].
A methodology is efficient only when it is accepted by all the actors in the construction process, and the
concepts and responsibility of every intervenient are clarified, namely those of the owner, the manager, the
architect, the engineers, the contractor, the maker, the condominium management firm and the users.
In the case of current buildings, a subdivision in two groups (buildings at the design stage and existing
buildings) is proposed, notwithstanding general aspects related for example with normative requirements
or with available technology and materials.
For buildings at the design stage, procedures that guarantee maintenance planning need to be
implemented, taking into account each project’s characteristics, the materials to be applied and local
conditions. It is at the design stage that it is possible to make the project solutions flexible in terms of
durability, maintenance needs and access to perform those actions. The implementation of these
procedures will minimize the occurrence of anomalies at the service stage (43% of all the anomalies have
their origin in design errors) [2] and global costs.
For existing buildings, it is necessary to take into account its specificity in terms of existing degradation
states, users’ expectations / claims, intervention needs, intervention urgency, economic availability,
building history / records, etc.. The interventions in existing buildings are of a specific type, inherent to
buildings in use, where the absence of planning of the interventions causes important extra-costs (it is well
known that for an enterprise with a life-span of 50 years the expenses related with the design and
construction stages amount to about 20 to 25% of the global costs, while the in service and maintenance
stage represents around 75 to 80% of the same costs [3]).

XXXI IAHS, June 23-27, 2003, Montreal, Canada
With this subdivision the intention is to keep existing buildings within acceptable degradation levels and,
on the other hand, to create right from the design stage mechanisms to limit / control the degradation of
the various elements.
3 Methodology for buildings at the design stage
Even though the increase of the users’ demands has contributed to a higher quality level of design, this
improvement has not been translated at the level of compatibility of those demands or of the technological
choice of solutions based on their durability. The aspects related with maintenance remain neglected. On
the other hand, there is no concern from the designers with the service stage, thus making difficult the
correction of errors resulting from the design of inadequate solutions for certain service conditions.
The analysis of maintenance at the design stage is made difficult when there is no technical support with
detailed and consistent data to characterize the in service behaviour of the various elements of the
buildings. In Fig. 1 the methodology for buildings at the design stage is schematically presented.
Requirements
definition
- durability criteria;
- performance levels;
- degradation stages;
- legal requirements;
- etc..
- technical documents;
- databases;
- characterization tests ;
- prototypes;
- technical recomendations;
- etc..
Data collection
- architecture;
- engineering;
- security plans;
- environmental studies;
- etc..
Design
analysis
Inspection and
maintenance plan
- maintenance actions;
- inspections;
- diagnosis methods;
- periodicity;
- priority criteria;
- costs estimation;
- decision criteria;
- procedures;
- etc..
Users’ manual
Technical
compilation
Figure 1: Methodology for proactive maintenance of buildings at the design phase.
3.1 Requirements definition
The requirements that are to be guaranteed in the building and its components must be defined, namely
mechanical strength and stability, safety in use, acoustic comfort, economy, environmental friendliness,
ecology, technology and durability, within a perspective of sustainability of the constructions and abiding
the existing laws. The complete characterization of the requirements follows the clear identification of the
influential agents, the way they express themselves and the calculation methods (experience, theoretical
models, in situ or laboratory tests or classification based on technical documents) [4].

Inês Flores Colen, Jorge de Brito
These parameters should establish the relationship between the intended levels of performance and
durability - levels of quality, associated to different degradation states, physical or functional. It is also
important to characterize the levels of quality for the various elements that correspond to the minimum
acceptable requirements.
3.2 Data collection
Data must be standardized by typifying the different solutions for the buildings elements. The construction
of a data base with several relevant parameters (expected service lives, relevant anomalies, probable
causes, degradation mechanisms and maintenance costs) will allow a greater knowledge of the in service
behaviour of the elements, encouraging the use of a periodic and planned maintenance. In this sense it is
important to perform characterization tests of the construction solutions, in laboratory, in situ or even with
prototypes, monitoring materials, products and systems. The detailed characterization of the different
buildings can also be an important piece of data in the comparative analysis and design of new buildings.
3.3 Analysis of the construction design
In order to analyse the design, it is necessary to check the various project elements, written and drawn,
related with architecture and engineering. It is also necessary to guarantee flexibility in the design
allowing for the future application of new construction solutions, in order to prevent obsolescence.
The design of new buildings should guarantee the existence of adequate and safe access for the
performance of maintenance operations. In this context, interventions may occur regularly at efficient
costs and with high quality and safety. Dealing with accessibility at the design stage is a performance
criterion that affects the feasibility of the various maintenance operations.
3.4 Maintenance documentation
Complementing the construction project, specific design elements for buildings maintenance should exist
that, even though or because developed at this early stage, have a dynamic character and are updated
throughout the service life of the buildings. These documents contribute to reporting the occurrences and
interventions, thus constituting the buildings history.
3.4.1 Technical compilation
The technical compilation following the Safety Plan (prepared at the design stage referring to the
construction works) is not a common practice in Portugal even though compulsory by law. It generally
includes technical data relating to the projects and the documents concerning the equipment, aiming at the
prevention of professional risks in the maintenance and normal use interventions, such as works performed
in the façades, roofs, ducts and technical galleries.
3.4.2 Users’ manual
Users’ manuals can provide data / recommendations for the use of elements / equipment of the building,
functioning as operation manuals and predicting anomalies caused by deficient usage.

XXXI IAHS, June 23-27, 2003, Montreal, Canada
3.4.3 Inspection and maintenance plan
Inspection and maintenance plans should include the elements within the building that need maintenance
through their service life, comprising the envelope, the structure, outer and inner elements, fittings and
equipments. They should characterize the aspects related with decision, priority and periodicity of the
interventions and the various maintenance operations (inspections, cleaning, repairs / local replacements
and preventive treatments) as well as costs estimates.
4 Methodology for existing buildings
The initial presuppositions established at the design stage should be tested during the service stage of the
buildings and subjected to constant updating or there is the risk that the methodology may not apply to
their effective behaviour.
In existing buildings, where well-defined maintenance strategies do not exist, it is advisable that the
degradation state is characterized during a detailed inspection [5] that can be used as a reference to future
actions. In Fig. 2 the methodology for existing buildings is schematically presented.
Preventive
maintenance actions
Inspections
(predictive
maintenance)
- diagnosis methods;
- decision criteria;
- laboratorial tests;
- field tests;
- pathology symptoms;
- etc..
Reactive
maintenance actions
Urgent action
Interventions
planning
Procedure
Monitoring
Works execution Data recording and
feed back
- records;
- data post-treatment;
- maintenance documents
update;
- etc..
Figure 2: Methodology for proactive maintenance of existing buildings.
4.1 Maintenance actions
Maintenance actions will occur according to the elements prepared at the design stage, when applicable,
and may include:
 preventive maintenance actions, in order to timely control the appearance and propagation of
anomalies, by resorting to localized interventions;
 reactive maintenance actions, associated with unpredicted anomalies, with or without an urgency

Inês Flores Colen, Jorge de Brito
status;
 predictive maintenance actions (inspections) to calibrate the elements behaviour in service.
4.2 Procedure and diagnosis methods
Inspections must generally provide the permanent knowledge of the elements status that allows their
normal use, in acceptable safety conditions, and the minimization of the maintenance costs. These
inspections allow the timely detection of the first stages of unpredicted anomalies and define the
procedure, planning new maintenance actions. The actions post-inspection may be framed within the
following strategies: no action, localized corrective and preventive actions (the techniques to be used must
be defined) or monitoring of the propagation of certain anomalies.
Inspections require a valid diagnosis method that defines the anomalies, their causes and correctly
evaluates the degradation level of the elements [6]. Included in the data collected before the inspections,
there must be the interventions records and the design elements, with a prediction of the elements’ expected
behaviour, the quality levels intended and other data relevant to the analysis. All this data will contribute
to an efficient diagnosis of the present state of the element and to an adequate definition of the procedure.
There will also be a need to optimize inspections costs, as compared with the costs of future repair costs,
so that they are enough to make available the necessary means to obtain correct and efficient data.
4.3 Works execution
Actions are carried out taking into account the available budget and the satisfaction of the users’ demands
(defining priorities). All the work must be controlled and registered.
4.4 Data recording and feed back
The analysis of the records and the post-treatment of this data through a dynamic process contribute to the
continuous improvement of the methodology proposed, allowing the evaluation of the efficiency of the
intervention actions and techniques (reduction in “repathology” phenomena), the adequacy of the
predicted periodicity of the operations, the evaluation of the costs deviations and budget adjustments. It is
at the data post-treatment stage that important conclusions can be drawn such as: intervention needs,
average period between interventions, users’ expectations, elements performance, etc., enabling also the
return of relevant information to the designers.
5 Techno-scientific support of maintenance management
To make proactive maintenance viable, all the data must be systematized through a technical support to
back inspection and maintenance management, integrating informatics-based modules associated with
maintenance strategies. The fact that they are modular allows the future addition of supplementary
modules defining the service behaviour of each element, contributing to the characterization of the global
performance of the building itself. This technical support has the following objectives [7]:
 to become supporting data with valid and consistent information on the elements behaviour and on
techno-economic characteristics of the various maintenance operations;
 to register all the anomalies and the operations performed, thus making the building’s history;

XXXI IAHS, June 23-27, 2003, Montreal, Canada
 to systematize procedures, according to the strategy and shape of maintenance;
 to treat and update the basic data, improving in a continuous and sustained way the maintenance
methodologies.
In Fig. 3 the modules of techno-scientific support are listed.
Module 1
Objectives
Module 2
Technical options
Module 3
Technological
fundaments
Module 4
Maintenance
operations
Module 5
Planning
Module 6
Costs
Module 7
Economic tools
Modules 8, 9, and 10
Maintenance
strategies
Figure 3: Modules in a maintenance support system [7].
6 Conclusions
In order to make periodic and timely maintenance a reality, it is indispensable the implementation of
maintenance / rehabilitation methodologies from the design stage that contribute to the existence of more
efficient and economic interventions. It is also necessary to implement important measures in the
awareness and clarification of each intervenient’s responsibilities, with emphasis on the owner, the
manager, the architect, the engineers, the contractor, the maker, the condominium management firms and
the users.
The knowledge of the service performance of the building elements with a definition of the service life
contributes to the growing application of adequate maintenance methodologies, to the improvement of the
design and, therefore, to the minimization of the global costs.
A proactive methodology must be based on techno-scientific support, materialized by inspection and
maintenance plans defined at the design stage in new buildings or at the service stage in existing buildings.
With the definition of intervention types, periodicity and priorities, it is possible to identify the main
activity steps during the elements’ service life, in order to manage resources, costs and interventions.
These plans allow a continuous follow-up by structuring all the actions necessary for maintenance
according to different intervals and must be revised and updated annually. Their implementation will
render possible to cross various interventions and detect the critical periods, so that the maintenance
management and consequently the decision fall within the effective budgetary framings.
In order to develop a technical support to buildings maintenance, all the previous parameters must
integrate a data base and be optimized and monitored in inspections and records during the buildings
service stage. An adequate information system will decisively contribute to an improvement of the
knowledge in this area.

Inês Flores Colen, Jorge de Brito
References
[1] Flores, I.; Maintenance Strategies - Current Buildings Envelope Elements (in Portuguese), Masters
Thesis, IST, Lisbon, February 2002, 186p.
[2] CIB W86 - Building Pathology: A State-of-the-art Report, the Netherlands, CIB Report, 1993.
[3] Perret, J. - Guide de la Maintenance des Bâtiments. Moniteur Référence Technique, Paris, 1995.
[4] CSTB; MELTM - Manuel des Performances, Tome I, La Structure, L’Enveloppe Verticale.
[5] Flores Colen, I.; Proactive Maintenance Plans in Recent Buildings (in Portuguese), Proceedings of 3rd
Encore, LNEC, Lisbon, May 2003 (to be published).
[6] Flores Colen, I.; Brito J. - Vertical Envelope Maintenance - Application of Predictive Strategies (Part
II) (in Portuguese), Journal Arquitectura e Vida, No. 28, V. II, Lisbon, June 2002, pp. 90-95.
[7] Flores Colen, I; Brito, J, Building Façades Maintenance Support System, Proceedings of XXX IAHS
World Housing Congress - Housing Construction, V. 3, Coimbra, September 2002, pp. 1899-1907.