Journal of Software Engineering and Applications, 2012, 5, 297-303
http://dx.doi.org/10.4236/jsea.2012.55035 Published Online May 2012 (http://www.SciRP.org/journal/jsea) 297
Virtual Reality Technology Applied on Maintenance of
Painted Walls of Buildings
Alcínia Z. Sampaio, Daniel Rosário
Department of Civil Engineering and Architecture, Instituto Superior Técnico, Technical University of Lisbon, Lisbon, Portugal.
Received January 1st, 2012; revised February 29th, 2012; accepted March 23rd, 2012
ABSTRACT
In a building, the pain t co ating app lied to in terior walls conveys their aesthetic character and also performs an important
function of protection. It is a construction component which is exposed to agents of deterioration related to its use,
needing the regular evaluation of its state of repair. The completed model supports the performance of such periodic
inspections and the monitoring of interior wall maintenance, using Virtual Reality (VR) technology. Used during an
inspection visit, the ap plication allows users to consult a databa se of irregularities, normally associated with paint coat-
ing, classified by the most probable causes and by recommended repair methodologies. In addition, with this model, a
chromatic scale related to the degree of de terioration of the coating, defined as a function of the time between the dates
of the applicatio n of th e pain t and th e sched uled repa intin g, can be attributed to each element of coating monitored. This
use of VR technology allows inspections and the evaluation of the degree of wear and tear of materials to be carried out
in a highly direct and intuitive manner. The computer application has a positive contribution to make in the field of
construction, using as it does Information Technology (IT) tools which give access to innovative technology with it
capacity for interaction and visualization.
Keywords: Virtual Reality; Interactive Model; Buildings; Maintenance; Inspection
1. Introduction
The coating app lied to building walls, naturally, performs
an important aesthetic function: it is, howev er, essentially
a protective element for the substrate on which it is ap-
plied as far as the action of environmental agents of wear
and tear is concerned. The coating is fundamental to a
proper overall performance of a building throughout its
working life.
Materials frequently used in the coating of ordinary
buildings are: paint, varnish, stone and ceramics [1]. In
Portugal, where interior walls are concerned, the most
commonly used coating is paint. It is a multi-purpose
material, used under a variety of decorative effects, based
on a widely-ranging palette of colours, patterns and tex-
tures and is easily applied on any type of surface. In ad-
dition, paint, compared to other materials, is less costly,
not only as far as the product itself is concerned, but also
in its application, since relatively non-specialised labour
is required. Nevertheless, as deterioration is a given,
maintenance is needed.
Factors such as the constant exposure of the coating to
the weather, pollutants and the normal actio ns of housing
use, linked to its natural ageing and , in some cases to the
unsuitable application of systems of painting give rise to
its deterioration and to the appearance of irregularities,
which can negatively affect its performance as both an
aesthetic and a protective element. According to Lopes
[2], in normal conditions of expo sure and when correctly
applied a paint coating can remain unaltered for about
five years. Establishing suitable maintenance strategies
for this type of coating is based on the knowledge of the
most frequent irregularities, the analysis of the respective
causes and the study of the most suitable repair method-
ologies.
Currently, the management of information related to
the maintenance of buildings is based on the planning of
action to be taken and on the log of completed work. The
capacity to visualize the process can be added through
the use of three-dimensional (3D) models which, facili-
tate the interpretation and understanding of target ele-
ments of maintenance and of 4D models (3D + time)
through which th e evolution of deterioration can be visu-
ally demonstrated and understood. Furthermore, the pos-
sibility of interaction with the geometric models can be
provided through the use of Virtu al Technology (VR).
The work presented here is part of an on-going re-
search project: Virtual Reality technology applied as a
support tool to the planning of construction maintenance.

Virtual Reality Technology Applied on Maintenance of Painted Walls of Buildings 298
PTDC/ECM/67748/2006 [3] and as such is a component
of the Project focussing on the support of the mainte-
nance activity planning with particular reference to paint
coating applied to in terior walls of buildings for housing.
The completed virtual model id entifies the elements of
the building which make up the interior wall coating so
that monitoring can take place. The application is sup-
ported by a database, created for the purpose, of irregu-
larities, their probable causes and suitable repair proc-
esses, which facilitates the inspection process. The in-
formation is recorded and associated to each monitored
element, allowing subseque ntly, the inspection and repair
activity log to be consulted, thus providing a tool for the
definition of a rehabilitation strategy.
In addition, the model assigns a colour to each of the
coating elements, the colours defined by the time vari-
able, so that the evolution of the deterioration of the
coating material is clearly shown through the alteration
in colour. The prototype is, then, a 4D model.
The model integrates a virtual environment with an
application developed in Visual Basic programming lan-
guage. This allows interaction with the 3D model of
buildings in such a way that it becomes possible to fol-
low the process of monitoring the coating elements, spe-
cifically, painted interior walls, in terms of maintenance,
throughout th e life-cycle of the bu ilding.
2. Maintenance
The General Regulations for Urban Buildings (RGEU) [4]
stipulates the frequency of maintenance work, stating
that existing buildings must be repaired and undergo
maintenance at least once every eight years with the aim
of eliminating defects arising from normal wear and tear
and to maintain then in good usable condition in all as-
pects of housing use refe rred to in that document.
The time-limit indicated is applicable to all elements
of the buildings generally. It is clear, however, that the
regulatory period is too long for some specific compo-
nents and that, frequently enough, the time-limits for
action are not respected. There are, too, inefficient rent
policies, leading to long periods without rehabilitation,
and that the prevailing culture is one of reaction on the
part of the various parties involved in the maintenance
process. To these aspects should also be added the de-
fects sometimes registered during the construction of
property developments, exacerbating the poor state of
repair of the buildings. This gives rise to numerous ir-
regularities which, in turn, frequently lead s to inadequate
safety conditions.
According to Cóias [5], the purpose of maintenance is
to prolong the useful life of the building and to encour-
age adherence to the demands of safety and fun ctionality,
keeping in mind the specific set of conditions of each
case and its budgetary considerations. Satisfactory man-
agement of this activity is carried out by putting into
practice a maintenance plan which must take into con-
sideration technical, economic, and functional aspects
arising with each case.
Collen [6] points out that investment in the mainte-
nance and rehabilitation sector in Portugal is still weak
compared to that in the same sector in the construction
industry in the other countries of the European Commu-
nity. She makes it clear, however, on a more positive
note, that some measures have already begun to be im-
plemented here: some urban regeneration programmes
have been created, legislation, which focuses on the sus-
tainability of building s, has been laid down, and the revi-
sion of constructive solutions has been carried out, all
with the objective of guaranteeing that the maintenance
of built heritage be an integral part of the construction
sector.
The maintenance of buildings, then, is an activity of
considerable importan ce within the co n struction ind u stry;
its contributory aspects of conservation and rehabilitation
work need to be supported by correct methodologies of
action, underpinned by scientific criteria and by suitable
processes for the diagnosis of irregularities and the
evaluation of their causes.
This paper aims to make a positive contribution to this
field using the new computer technology tools of visu-
alisation and interaction.
3. Pathologies in Paint Coatings
The technical document Paints, Varnishes and Painted
Coatings for Civil Construction published by The Na-
tional Laboratory for Civil Engineering (LNEC), defines
paint as a mixture essentially made up of pigments,
binder, vehicle and additives [1]. It has a pigmented,
pasty composition, and when applied in a fine layer to a
surface, presents, after the dispersion of volatile products,
the appearance of a solid, coloured and opaque film [7].
The durability of the painted coating depends on the
environment in which it is used, and on the surface it is
applied to as well as the rate of deterioration of the
binder in the paint. The influence of the environment is
the result of the action, in conjunction or alone, of a vari-
ety of factors such as the degree of humidity, the levels
of ultraviolet radiation, oxygen, ozone and alkalis, varia-
tions in temperature and of other physical or chemical
agents whose effect depends considerably on the time
taken to apply it [8]. When their influence is not coun-
teracted or minimised, imperfections can arise in the
coating film, such as, the appearance of defects in the
layer or paint with the loss of functionality where the
desired aim of the application is concerned.
These irregularities manifest themselves in various

Virtual Reality Technology Applied on Maintenance of Painted Walls of Buildings 299
of deterioration of the coating [10]. The following com-
putational systems were used in its development: Auto-
CAD, in the creation of the 3D model of the building;
EON Studio [11], for the programming of the interactive-
ity capacities integrated with the geometric model; Visual
Basic 6 in the creation of all the windows of the application
and in the establishment of links between components.
All the systems were made available by the ISTAR/
DECivil [12], of the Technical University of Lisbon.
ways and in different degrees of severity. Based on the
study made of the causes of the defects, specific method-
ologies for their resolution were established. Figure 1
shows common defects in painted interior walls.
The information gained from the pathological analysis
of this type of coating was used to draw up a database
supporting the interactive application. These data support
the creation of inspection files related to the elements
which are monitored in each case stud ied.
In order to form a user-friendly database of relatable
data, groups of pathologies, shown below in Table 1,
were considered. This classification provides the required
automatism of access to the database and supports the
presentation of synopses of the causes and repair meth-
odology inherent in each pathology.
During the process of an on-site inspection , the user of
the application can refer to the database in order to clas-
sify the abnormality bein g observed, consulting the list of
defects, which includes, in addition to th eir identification,
the most relevant characteristics and some of the causes
that could be at the root of their development. Table 2
lists two of the irregularities from the classification: Al-
teration in colour.
4. Interactive Model
The completed application supports on-site inspections
and the on-going analysis of the evolution of the degree Figure 1. Swelling, efflorescence, cracking and blistering
[9].
Table 1. Classification of irregularities.
Classification Irregularity Repair methodology
Yellowing
Bronzing
Fading
Spotting
Loss of gloss
Alteration in Colour
Loss of hiding power
- Cleaning the surface and repainting with a finish both co mpatible with
the existing coat and resistant to the prevailing conditions of exposure in
its environment.
Dirt pick-up and retention
Deposits Viscosity - Cleaning the surface.
Efflorescence
Sweating
Cracking
Chalking
Changes in Texture
Saponification
- Removal by brushing scraping or washing;
- repainting the surface;
- When necessary apply sealer before repainting.
Peeling
Flaking Reduction in Adhesion
Swelling
- Proceed by totally or partially removing the coat of paint;
- Check the condition of the base and proceed with its repair where
necessary;
- Prepare the base of the paint work.

Virtual Reality Technology Applied on Maintenance of Painted Walls of Buildings 300
Table 2. Irregularities and causes.
Classification Irregularity Characteristics and causes
Yellowing
- A yellow colour caused by age in g of t h e fi lm of the paint or varnish;
- Action of environmental agents (solar radiation, temperature oxygen
and humidity) on the binder in the paint provoking changes in its mo-
lecular structure;
Alteration in colour
Discolouration
- Partial loss of colour of the film of paint coating;
- Action of environmental agents (solar radiation, temperature, polluted
atmosphere and chemically aggressive bases of application) on the binder
and/or the pigments of the painted coating.
The main interface gives access to the virtual model of
the building and to the inspection and mainten ance mod-
ules (highlighted in Figure 2).
The first step is to make a detailed description of the
building (location, year of construction, type of struc-
ture..., Figure 3) and representative modelled elements
of the interior wall coating, so that they can be moni-
tored.
The model is manipulated in the virtual environment
by using the mouse buttons (movement through the inte-
rior of the model and orientation of the camera, Figure
4). The coordinates of the observer’s position and the
direction of his/her point of view are associated with the
element during the process of identification.
Thus, later, when an element in the database of the ap-
plication is selected using the in terface, the model is dis-
played in the visualisation window so that the target
coating can be obser ve d.
Walking through the model with the aim of accessing
all the elements of the building, the user needs to be able
to go up and down stairs or open doors or windows. Th e
virtual model has been programmed, using the EON sys-
tem, in such a way that these capacities are activated by
positioning the cursor over the respective objects, in that
way, the user is able to walk through the whole model.
Each wall surface in each of the rooms of the house is
a component which has to be monitored and, therefore, to
be identified. Using the model, the user must click the
mouse on an element, and the message New Element is
shown (highlighted in Figure 2). Associated to this se-
lected element is the information regarding location
within the house (hall, bedroom), wall type (simple in-
ternal masonry wall) and coating (paint), as shown in
Figure 5.
4.1. Making an Inspection
Later, on an on-site inspection visit, the element to be
analysed it selected interactively on the virtual model.
The inspection sheet (Figure 6) is accessed by using the
Inspection button which is found in the main interface
(Figure 2). The data which identify the selected element
are transferred to the initial data boxes on the displayed
page (Figure 6).
Inspection Maintenance
Element not yet in database?
Add?
OK / Cancel
Figure 2. The main interface of the virtual application.
Characteristics of the building
Figure 3. Interface for the detailed description of the build-
ing.
Coordinates of the virtual model
Orientation of the virtual model
Figure 4. Coordinates and manipulation commands in the
virtual model.

Virtual Reality Technology Applied on Maintenance of Painted Walls of Buildings 301
Figure 5. Identification of an element in the virtual model.
Inspect New Element Case History
Number of anomalies
Figure 6. Presentation of the information introduced into
the inspection sheet.
Next, using the data base, the irregularity which cor-
responds to the observed defect, with its probable cause
(ageing) and the prescribed repair methodology (removal
and repainting) is selected (see highlighted area, Figure
7).
The current size of the pathology should also be indi-
cated since it reveals how serious it is (area of pathology,
Figure 7). In the field Observations, the inspector can
add any relevant comment (Figure 6), photographs ob-
tained on site can also be inserted into the inspection
window and the date of the on-site visit an d the ID of the
inspector should als o be added.
Several different irregularities in the same coating can
be analysed (field Number of Pathologies, Figure 6) and
other elements can be analysed and recorded and defects
observed. Later, the files thus created, associated to each
of the virtual model elements, can be consulted (Case
History button in the Interface in Figure 6). This same
window allows all the data referring to the building and
to the completed inspection to be shown, in pdf format
(Figure 8).
4.2. Maintenance Monitoring
How long the working life of any construction compo-
nent might be is an estimate and depends on a set of
modifying factors related to their inherent characteristics
of quality, to the environment in which the building is set
Pathologies
Causes
Repair methodolo gy
Area of pathology
Figure 7. Interface for the selection of the irregularity,
probable cause, area and repair methodology.
Pathologies/Causes/ Repair Methodologies
Pathology: Peeling
Cause: Natural ageing of paint coating
Repair methodology: To t al o r pa rt ia l r emo v a l o f p ai nt co a ti ng . C he ck co n ditio n o f t he
base and repair as necessar y. Carry out the preparation of the base and the painting
Observations
No relev ant observa tions to be recorde d
Manager
Element details
Location: Hall 1
Type of wall: I nterior
Description Details: Simple ma so nry wall
Coating: Paint
Ins
p
ect i on s he e
t
Figure 8. Inspection sheet.
and to its conditions of use [5].
In maintenance strategy planning the probable dates
when adverse effects might occur in each of these ele-
ments must be foreseen, and the factors which contribute

Virtual Reality Technology Applied on Maintenance of Painted Walls of Buildings 302
to defects must be reduced and their consequences mini-
mized.
The completed model allows the user to monitor the
evolution of wear and tear on the pa int coatin g in a hou se.
For this, technical information relative to the reference
for the paint used, its durability and the date of its most
recent application must be added (Figure 9) to each ele-
ment through the Maintenance Interface (also accessed
from the main interface, Figure 2).
Based on these data, it is possible to link in the date
the virtual model is consulted and visualise, in the geo-
metric model, the level of wear and tear as a function of
time (see state of repair, Figure 9). The period of time
between the date indicated and the date when the paint
was applied is compared to the duration advised, in the
technical literature, for repainting. The value given for
this comparison is associated to the Red, Green, Blue
(RGB) parameters which define the colour used for wall
in the virtual model (Figure 10).
In this way, the colour visualised on the monitored
wall varies according to the period of time calculated,
pale green being the colour referring to the date of paint-
ing and red indicating that the date the model was con-
sulted coincides with that advised for repainting (Fig-
ure 10).
The data for painting and repain ting are saved to a list
Technical and commercial characteristics
State of repair
Figure 9. Technical characteristics and the durability of the
paint-work.
Figure 10. Chromatic alteration of the coating according to
its state of deterioration.
of coating elements to be monitored in the virtual model
(Figure 11). When an element is selected from this list,
the corresponding element is represented in the virtual
model, through the preview window, in the colour that
corresponds to the period of the consultation (Figure 10).
5. Conclusions
This application supports the maintenance of painted
interior walls and promotes the use of IT tools with ad-
vanced graphic and interactive capabilities in order to
facilitate and expedite the insp ection process. The virtual
model, moreover, allows users to see, in the virtual envi-
ronment, the state of repair of the coating.
The information about pathologies, causes and repair
methods, collected from a specialised bibliography, has
been organised in such a way as to establish a database to
be used as a base for the drawing up of a tool to support
building mainten ance. The main aim of the application is
to facilitate maintenance enabling the rapid and easy
identification of irregularities, as well as the possible
prediction of their occurrence through the available in-
spection record. This an alysis has been shown as playing
an important role in conservation and in the reduction of
costs related to the wear and tear of buildings and con-
tributes to the better management of buildings where
maintenance is concerned.
In addition to the inspection component, a mainte-
nance component was developed which, being visualized
in a VR environment, as well as being highly intuitive,
facilitates the analysis of the state of repair of buildings.
By means of a chromatic scale applied to the monitored
elements, displayed in the walk-through of the geometri-
cally modelled building, it is possible to identify the
elements which, predictably, will need timely action.
With the possibility of altering the time parameter freely,
the user can carry out this analysis either for past instants
or for future events, being able, in this way, to forecast
future operations. This capacity of the model, therefore,
contributes to the avoidance of costs associated to ir-
regularities which, with the passage of time, become more
serious and therefore more onerous.
6. Acknowledgements
The authors wish to thank the Foundation for Science
and Technology for the financial support given for the
development of the research project Virtual Reality
Figure 11. Information relevant to the monitored elements.

Virtual Reality Technology Applied on Maintenance of Painted Walls of Buildings 303
technology applied as a support tool to the planning of con-
struction maintenance. PTDC/ECM/67748/2006 (2008-
2011).
REFERENCES
[1] M. Eusébio and M. Rodrigues, “Paints, Varnishes and
Painted Coatings for Civil Construction,” CS 14, National
Laboratory for Civil Engineering, Lisbon, 2009.
[2] C. Lopes, “Anomalies in Painted Exterior Walls: Technic
of Inspection and Structural Eval uation,” Construlink Pre ss,
Lisbon, 2004.
[3] A. Z. Sampaio and A. Go mes, “Virtual Reality Technology
Applied as a Support Tool to the Planning of Construction
Maintenance,” Research Project PTDC/ECM/67748, FCT,
Lisbon, 2006.
[4] “RGEU-General Regulations for Urban Buildings,” De-
cree-Law, Lisbon, 1951.
[5] V. Cóias, “Inspections and Essays on Rehabilitation of
Buildings,” 2nd Edition, IST Press, Lisbon, 2009, p. 448.
[6] I. F. Collen, “Periodic Inspections in Buildings,” Planet
CAD Studies, 2003.
http://www.planetacad.com/presentationlayer/Estudo_01.
aspx?id=13&canal _ordem=0403
[7] M. B. Farinha, “Con struct ion of Buil ding s in Practice : Guide
Oriented to the Development of Processes and Methodolo-
gies of Construction,” Verlag Dashofer, Psicosoma, Lisbon,
2010. http://www .psicosom a.pt/
[8] M. I. Marques, “Durability of Plastic Tint,” ITMC 2, Na-
tional Laboratory for Civil Engineering, Lisbon, 1985.
[9] A. Moura, “Characteristics and Conservation State of Painted
Façades: Study Case in Coimbra,” Master Dissertation in
Construction, Technical University of Coimbra, Coimbra,
2008.
[10] D. P. Rosário, “Virtual Reality Technology Applied on Bu-
ilding Maintenance: Painted Interior Walls,” Master Dis-
sertation in Construction, Technical University of Lisbon,
Lisbon, 2011 .
[11] “EON Studio. Introduction to Working in EON Studio,”
EON Reality, Inc., 2011. http://www.eonreality.com/
[12] “ISTAR—Architectural Laborato ry of IST,” Lisbon, 2011 .
https://fenix.ist.utl.pt/departamentos/decivil/
lateral/o-ecivil/unidades-de-apoio/laboratorios-informati
cos