PROVISIONAL PLAN OF MAINTENANCE IN HISTORIC BUILDINGS

Daniel Nóbrega Tomásio Lopes Soares

Extended abstract

December 2012

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1. INTRODUCTION

The maintenance of historic buildings is a subject which is neither very well-known nor developed in

Portugal, with lack of continuum research when compared with other European countries.

In recent years a philosophy of proactive maintenance has been developed, mainly applied in current

buildings, allowing the detection of problems before they affect the users of the building as well as

reducing costs of corrective actions of maintenance applied during buildings’ service.

This reality cannot be fully transposed to the case of historic buildings, but it helps to motivate and

develop the scientific process associated with maintenance methodologies. In the case of historic

buildings, there are different concerns often related with the ability of these buildings to generate

profits associated with tourism. In recent years there has been a greater awareness of the importance

of heritage and its role in consumer society.

The aim of this work is to create a methodology for proper maintenance of historic buildings, taking

into account their unique characteristics and respecting the issues associated with authenticity. The

maintenance actions will be described through a plan, applied to a case study, with estimated costs for

a timeline of 10 years.

2. SCOPE OF MAINTENANCE AND HISTORIC BUILDINGS

A historic building is defined not only by its architectural nature, but also by its historic testimony.

Therefore it will be a cultural property (classified or in the process of classification), which by its type of

construction and architecture conserves a historic testimony of the region or place where it belongs.

The origins of maintenance are mainly linked to the industrial field, being considered as a means for

technical development, not only from a conceptual point of view but also from the strategic and

management view, factor that will later influence the choice of preventive methodologies applied to

buildings.

In this work it will be important to recognize different possible interventions in buildings in order to

improve performance levels depending on the type of work involved. There are several concepts

which are important to differentiate in each analysis.

Small repairs and occasional intervention with the aim of bringing the building for adequate

performance levels are included in maintenance. Focusing on the topic from the perspective of civil

engineering, the definition of maintenance of buildings is associated to the combination of all technical

and associated administrative actions during the service life to retain a building or its parts in a state in

which it can perform its required functions (ISO 15686, 2011).

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If the state of degradation increases significantly deeper intervention will be needed, prolonging the life

cycle of the building/element. In this case, it is more appropriate to use the with the increase of

intervention degree: refurbishment, renewal, reconstruction (Manso, 2003).

In this context it is also important to define the conservation concept. This can be defined as the first

level of intervention to be applied to the historic heritage, so that it remains in a state of appropriate

preservation, and without existing a profound degradation in its elements. As mentioned in the Venice

Charter (Weaver, 1997), the conservation of a monument implies preserving a framework that is not

out of scale. Wherever the traditional setting exists, it must be maintained, and should not be adopted

any new construction, demolition or modification which will change the relationship of the original

monument.

The existing definitions in ISO 15686 (2011) are usually linked to the concept of life cycle of the

building. That’s the reason why its philosophy and methods of analysis cannot be entirely transported

to the full scope of historic buildings, an area where the lifetime of some materials and elements has

long been exceeded.

i) Portuguese experience:

The sector of construction in Portugal has investing in new construction over the years, within this

sphere (Figure 1) exist a small field but with growing importance, that corresponds to works of

refurbishment in existing buildings. In Portugal this sphere has a value of less than 10% of the total

construction, while in other European countries it is 40 to 50%. The third sphere is concerned with the

conservation and restoration of monuments and historic buildings, the noblest part of the built

heritage: buildings which, besides being constructions, are also cultural goods. The latter sphere

covers less than 1% of total production in the construction sector (Cóias, 2009).

Existing legislation in Portugal over maintenance is outdated, and the only existing regulation is RGEU

(General Regulation of Urban Construction), which has been revised and is waiting for approval,

changing its name to RGE (Regulation of General Buildings). It should be noted that the updated

General construction

Refurbishment of buildings

Heritage conservation

Figure 1 – Representatives spheres of activities in the construction sector (adapted from Cóias, 2009)

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RGEU does not include any article or specificity regarding the maintenance on historic buildings,

although there are several important changes envisaged in the chapter on Maintenance and

Durability.

Apart from the maintenance of historic buildings in Portugal, it is important to analyze what has been

done in other countries. So the following cases have been described:

ii) International experience:

the Italian experience, which due to its pioneering and conservation model applied to the

territory was the largest contributor to the development of the theme at an european level;

the English experience, with especial importance due its pragmatism addressing the problems

dealing with the conservation of monuments, as well as its experience in implementing

preventive and pro-active strategies in their churches and cathedrals, has been providing

good indications about the financial relevance of this type of approaches.

the Dutch initiative has proved a success in terms of application and financial advantages,

reason why it has been followed by several countries.

3. METHODOLOGY OF MAINTENANCE IN HISTORIC BUILDINGS

Throughout the application of this methodology it should be taken into account some characteristics

that differentiate this type of buildings such as:

heterogeneity of existing monuments, with different periods of construction and different

construction techniques;

cultural appreciation for the zone in which they are involved;

authenticity of unique elements, where the aim is not to replace but to save;

buildings often subjected to daily tours.

The methodology described can be applied to any historic building, taking into account that changes

may be made in the formulations presented, depending on each case study.

A maintenance plan designed specifically for historic properties introduces the concept of preventive

conservation, i.e. we must be especially careful with all interventions made, replacing only what is

essential and preserving what is unique and historic. The purpose is to monitor the performance of the

building, preventing the emergence and deterioration of predictable anomalies. Efficient management

of these routines, organized technically on a plan, allows not only greater longevity of the elements

studied, as improves the building daily functioning, for all those who use or visit it.

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This document provides maintenance management through the identification of future interventions,

who runs them and what their periodicity. In addition, it serves as an important tool for monitoring the

building, allowing control costs associated with maintenance. The maintenance plan assumes a

character both technical (operating instrument) and economic, being possible to estimate financial

needs by programmed actions.

The methodology developed is shown in Figure 2 and is spread over several phases. Initially it will be

presented the preliminary phase, targeted for the study of the intrinsic characteristics of the building

under study and the environment that surrounds it. Then there will be the phase of inspections, where

through various surveys one can divide the building into different facilities, studying the state of

degradation of each one scaling the maintenance actions. Finally, the maintenance plan will be

prepared, accompanied by decision criteria based on rationalization and opportunity.

Figure 3 - Proposed methodology for maintenance on historic buildings

- Description of the historic building

- Changes made to heritage over the time

- Importance of the building to the region

- Characterization of the entities responsible for the

management and maintenance

- What type of maintenance is performed

- What is the current condition of the building

- Study of the environmental conditions of the region

- Human risk factors

- Possible funding problems

- Check for existing maintenance material

- Check for emergency routes

- Gather information on touristic visits

- Floor plans and elevations

- Photografies

- Accessibilities

- Previous interventions

- Physical condition

- State of degradation

- Observed anomalies

- Frequency

- Criteria for priority

- Description of the inteventions

- Material

- Equipment

- Workmanship

Previsional plan of maintenance

- Different scenarios

- Rationalization/means synergy

- Opportunity factors

2 - Inspections

phase and

maintenance

program

A - Survey data

E - Maintenace costs

1 - Preliminary

phase to

development of

the plan

A - Building comprehension

B - Current situation of the building

C - Study of the environment and potential

risks

D - Internal management of the building

3 - Decision - Economic Analysis

Sheets survey

B - Information organizationInspection sheet

nº 1

C - Study of materialsInspection sheet

nº 2

D - Maintenance actionsInspection sheet

nº 3 (criteria)

- Division of the building in facilities

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4. CASE STUDY

At this stage the maintenance methodology presented in the previous chapter will be applied to a

historic building. As a case study will be used the National Pantheon, a building located in the historic

district of Santa Clara in Lisbon, and classified as a National Monument.

The description of the building and its surroundings will be done initially, followed by previous

interventions and data collection. After that the monument will be divided in facilities, and the

campaign inspections will start.

4.1. Preliminary phase to development of the plan

The National Pantheon, located in the Lisbon, occupies the building originally intended for the church

of Santa Engrácia, hosting the tombs of the great figures of Portuguese history. The current

guardianship of the building belongs to the Institute for Managing the Architectural and Archaeological

Heritage (IGESPAR), a public body within the Ministry of Culture, with responsibilities for the

architectural and archaeological heritage in Portugal.

This building is a key reference in the profile of the city (Figures 4 and 5), offering privileged views

over the old town and the Tagus River.

This ancient church, severely damaged by a storm in 1681, was completely rebuilt by architect João

Antunes. The death of the Royal Architect, in 1712, resulted in the virtual abandonment of the work,

deprecated by King D.João V. After the extinction of the religious orders in 1834, the church served as

a depository of war material and as factory of clothing and footwear. The works lasted so long that

gave rise to the popular expression "works of Santa Engrácia" to designate something that takes a

long time to finish. The building eventually receives its dome only in 1966.

Figure 4 – National Pantheon, view from Tagus River

Figure 5 – National Pantheon, aerial view

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It is a building with classical architecture assimilated to the Baroque, Greek cross plan with three

chapels, central quadrangular space and four towers at the corners. The structure is characterized by

having sturdy resistant masonry walls.

The recent dome (1966) is characterized by a totally different type of construction, with reinforced

concrete structure coated with stone as can be seen by Figures 6 and 7.

Figures 6 and 7 – Dome construction by the DGEMN, 1964

4.2. Inspections phase and maintenance program

Previous operations performed on the monument were monitored by the former General Board for

National Buildings and Monuments (DGEMN), and the existing documents were passed to the

Information System for Architectural Heritage (SIPA). A research conducted on this platform met some

old building plants and an elevation, this information was completed and transposed into digital form,

this way is possible to have an architectural and functional survey of the building, easy to use, which

enables the measurement of elements in an expeditious manner.

As described in the presentation of the methodology in Chapter 3, should be created a complete list

identifying all the maintenance elements existing in the historic building under study.

In order to implement this system in maintenance plans for historic buildings the Italian standard for

facilities management (Lobo de Carvalho, 2007) has been adapted, consisting on an alphanumeric

code, with two parts: the identification of the element in context of the constructive system (in text

characters) and its functional location and sequential numbering (in Arabic numerals).

Figure 8 – Example of the maintenance elements codification

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In the example of Figure 8 the coding of the maintenance element is made by specifying its class (in

textual characters), followed by its spatial location and numbered sequentially (in Arabic numerals), in

this example refers to simple glass element (Gl) from the technological class Window (WIn), located

on the facade 026, number 2.

After verifying the compatibility of the collected data with the code presented, the inspection phase has

begun through inspection sheet nº1 (extract in Table 1). The information presented here is just an

example. Around 500 maintenance elements along all facades and roofs of the monument have been

collected in this study.

Table 1 – Extract from the inspection sheet nº1

Cost center

Area Group cod. Class cod. Element Quantity

(un/m/m2) Date

Complete element code

Façade Vertical str. (EXw) Exterior wall (Sm) Stone masonry 816,0 m2

19.11.12 EXwSm 001-1

Façade Vertical str. (EXw) Exterior wall (Sw) Stonework 21,5 m2

19.11.12 EXwSw 001-1

Façade Vertical str. (EXw) Exterior wall (Sw) Stonework 91,0 m2 19.11.12 EXwSw 001-2

After identified all the maintenance elements on the facades and roof, starts the evaluation phase of

the state of degradation.

The most serious anomalies observed in the front facade are associated with disruption of masonry;

the principal cause for the problem is the absence of anti-bird protection. This facade has three stone

statuary (as opposed to other facades that have none), serving as a local of pigeons aggregation, a

factor that accelerates the degradation in these areas (Figure 9).

Figure 9 – Agglomeration of pigeons in the statuary of the main facade

This situation should be corrected as quickly as possible; in certain areas are already visible pecking

zones from the pigeons, and the droppings at the place act as chemical aggression factor. It is

advisable to place networks anti-pigeon areas in the statuary, and a system of plate needles in the

upper region of the masonry.

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It should be noted that although the symmetry of the building and the apparent similarity between all

walls, the several facades presents different anomalies.

Due to the geographical location of the building and the surrounding environment, the lateral facades

contain anomalies related to human presence. The south facade features plenty of graffiti, a situation

that makes the stone cleanness more expensive (Figure 10). The north facade is close to Campo de

Santa Clara, venue that hosts the flea market twice a week, this facade is currently used as a public

toilet (Figure 11), a situation that causes several anomalies related to urine in contact with the stone.

Figure 10 – Graffiti zone in the South facade

Owing to the special nature of the place, it would be advisable to limit the access to this area of the

monument, for example installing a fence that reduces access to this place.

In the roof areas the major defects are associated with the existing stormwater drains. In the terrace

area there is a single gutter that surrounds the entire building (Figure 12) and discharges into several

downpipes. It’s possible to see through the inspections that most of the downpipes are blocked (many

of them do not have drains pine cones), that’s the main reason why the water remains in coverage as

shown in Figure 13.

The rainwater drainage systems existing on the roof should suffer cleaning interventions within a short

time.

Figure 11 – Accumulation of urine in the North facade

Figure 12 – Single gutter that bypasses the entire

terrace

Figure 13 – Gutter full of water, already visible parasitical vegetation

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The anomalies registered during the inspections should be pointed in the inspection sheet nº2 showed

in Table 2.

Table 2 – Extract from the inspection sheet nº1

Element code Element name

Degradation state of the facility Observed anomalies Possible causes

WA R B R

EXwSm 001-1

Stone masonry X Dirtiness Lack of cleanliness

EXwSw 001-1

Stone work x Black stains Accumulated dirt, grubbiness

Key: WA=Without Anomalies; R= Reasonable; B=Bad; R=Ruin

After this phase the classification of the criteria associated with facilities belonging to historic buildings

was elaborated.

It should be noted that the criteria "Cultural Value" (main criterion for differentiation between historic

buildings and current buildings) will adopted low values in some elements of the monument. Despite

being a XVII century building, the various reconstruction and extension of the works meant that much

of the building is from much recent construction.

Figure 14 – Monument division

The bottom of the monument is from the XVII century, while the upper part was constructed only in

1964 factor that causes the difference value (Figure 14).

According to the present Equation 1 the calculating of the scaling ratio relative to all elements existing

in the building has been made. On the Table 3 is presented as an example of the scaling ratios.

Low cultural value

Significant

cultural value

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(1)

Table 3 – Example of scaling index of the main facade

Facility code DS CV RF AC Weighted

index Relative

index Cost

center

EXwSm 001-1 2 2 2 3 33 0,77 Facade

EXwSw 001-1 3 2 2 3 38 0,88 Facade

EXwSw 001-2 3 2 2 3 38 0,88 Facade

WInGl 001-1 1 1 3 1 19 0,44 Span

Key: DS=Degradation state; CV=Cultural value; RF= Relation to other facilities; AC= Accessibility

(2)

Table 4 - Scheduling actions

Type of action

Maximum time until the next

intervention

Immediate ≥ 0.90 Immediate

Short-term 0.40 ≤ < 0.90 5 years

Long-term < 0.40 From 5 to 10 years

This type of scheduling actions will be very important for the next phase of the methodology, which

consists in preparing the provisional plan for maintenance. The maximum time for interventions is

described on the Table 4.

At this stage of the work, apart from the scaling operations already estimated, it is important to know

the periodicity that must be defined between each intervention. This information should be gathered

through technical catalogs, professionals with experience in maintenance and technical literature

directed to historic buildings.

Once collected all the necessary information has been possible to build the provisional program of

maintenance actions for the National Pantheon in Lisbon. In Table 5 is shown a representative form of

the plan for maintenance of the main facade.

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Table 5 - Representative form of the provisional plan of maintenance

After the development of the plan should exist a stage dedicated to the economic analysis. This way

it’s possible to study several intervention scenarios. It is important at this stage of the work to make a

rationalization/synergy of available means, trying to make a maintenance based in opportunity (e.g.

association of works taking in account the high cost of scaffolding assembly on the facades).

Table 6 – Provisional plan in associated costs for the main facade

5. CONCLUSIONS

To make the implementation process of maintenance plans (theme that has undergone major

developments in current buildings) is necessary to take into account the specificities associated with

historic heritage, including the different attributes of each building - each monument usually presents

unique characteristics - as well as issues relating to authenticity, a practice that in the past was not

privileged.

This work intended to develop a methodology for maintenance that could be applied to any historic

building, the ultimate goal is the development a provisional plan for maintenance actions and cost

estimates for each analyzed building.

Routine

Facility Code Type Pontual Month Anual Quinquennial Decennial Man power Equipment Total cost

Stone masonry EXw Sm 001-1 Cleaning x 2 workmen Eq. water jet 951,0 m2 14,76 €/m2 14.036,8 €

Stonew ork EXw Sw 001-1 Cleaning x 2 workmenEq. manual

brushes112,5 m2 14,98 €/m2 1.685,3 €

Glass WInGl 001-1 Substitution x x 1 workman Eq. Glass 6,0 m2 36,05 €/m2 216,3 €

Facilities codification Periodicity Means Costs

Quant. Price

Main Facade

2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023

Facade 19.110,2 €

Span/Porthole 1.489,0 € 1.900,4 €

Stonework 8.802,7 €

Systems 420 € (a) 24,3 € 31,0 €

Scaffolding 11.246,0 €

Anual costs: 420,0 € 0,0 € 0,0 € 0,0 € 40.672,2 € 0,0 € 0,0 € 0,0 € 0,0 € 1.931,4 € 0,0 €

(a) Anti-pigeons system 3.911,2 €Anual average costs to main facade:

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The application of the maintenance methodology created was implemented without much difficulty on

the case studies. However it was found that its application is both laborious and long, since each

building has been subject to several visits to complete the inspection sheets. The software used for

the calculation of the index of the maintenance elements needs was Microsoft Excel, which revealed

to be suitable for obtaining the required results.

The three inspection sheets drawn up to perform the visual inspections have allowed the collection of

nearly 500 elements in the monument. The data collected were applied to the hierarchy formula

previously developed and provided good results.

The application of the methodology developed on the historic buildings made it possible to obtain the

following data:

A list of building anomalies;

A provisional maintenance plan with needs for 10 years;

The maintenance associated costs for 10 years.

REFERENCES

Manso, A. (2003), Refurbishment and conservation of buildings: costs evaluation and recent

developments. 2º International Symposium of pathology, durability and refurbishment of buildings,:

LNEC, Lisbon.

ISO 15686-1 (2011), “Buildings and constructed assets - Service life planning - Part 1: General

principles and framework”, International Organization for Standardization, Swiss.

Cóias, V. (2009), Rehabilitation: the best way to sustainable construction; article present in “Banca e

Ambiente”, page. 2. Lisbon.

Rodrigues, R. (1989) Building Maintenance - Analysis and exploration of data on a residential park,

Thesis to obtain the Master’s Degree, FEUP, Oporto.

Flores, I. (2002), Maintenance strategies – Current building’s envelopes, Thesis to obtain the Master’s

Degree, IST, Lisbon.

Lobo de Carvalho, J. (2007). Heritage Conservation - Policies for Economic Sustainability. Thesis to

obtain the PhD Degree, IST, Lisbon.

Weaver, M. (1997). Conserving Buildings - A Manual of Techniques and Materials. Preservation

Press, John Wiley and Sons, inc.