Monitoring Heritage Buildings and Places

Monitoring is the act of observing something and keeping a record of it.

The central argument for monitoring can be stated in a single sentence: You cannot recognize, understand, improve or maintain what you do not or cannot measure.

Monitoring is the act of measuring change in the state, number, or presence of characteristics of something. It involves the repeated collection of a specific set or sets of information over time and analysing the results to detect the changes that are occurring. The collection of this information facilitates identification of recurrent problems or fabric susceptible to damage. The problem areas, once identified, can be monitored more intensively and, where appropriate, management action taken.

Before deciding on any monitoring activity, managers must ask themselves the following question: What is the purpose of the monitoring exercise? The more specific the answer to this question, the better will be the results. An unspecific monitoring brief will not provide the anticipated results.

Good and wide-ranging documentation review and preparation should precede any monitoring activity. As much information as possible about the building should be gathered from existing sources before deciding on monitoring activities.

In the case of heritage buildings monitoring involves measuring:

  • Changes in the external pressures acting on the property
  • Changes in the condition of the property
  • The effectiveness of management actions on conservation of the property's values.

Condition monitoring requires:

  • a long-term commitment;
  • a rigorously followed procedure for reporting monitoring observations and
  • adequate numbers of qualified personnel to carry out the monitoring.

For methodology and forms for monitoring various types of structures and sites, consult New Zealand's 2003 technical paper "Methods for monitoring the condition of historic places"

Basic questions for monitoring heritage buildings include: Is it stable, safe, dry, maintained, documented, regularly inspected, valued by the community, and interpreted? Following are a few examples of monitoring indicators, tools and purpose for heritage properties. Many tools and instruments can help those responsible for the care and maintenance of heritage buildings monitor the condition of those buildings. But in the end, nothing is a substitute for a keen eye, patient assessment, and human logic, all of which will always be needed to conserve the best of the past for the future.

Indicators Tools Purpose
Building Drainage

Hygrometer recording levels of moisture in basement, stains on foundations, walls and ceilings, downspouts and roof drains.


To determine where and how much moisture penetrates into the building.

Graffiti and vandalism

Visual observation, inventories To plan clean-up or to strengthen security measures.
Interior temperature variations


To determine if and when heat/cold may affect materials and finishes, collections and living conditions or comfort.
Interior relative humidity variations


To determine if and when condensation may occur inside the building or create conditions favorable to algae and fungus growth.
Maintenance techniques
Survey maintenance crews and maintenance work To determine if maintenance techniques or lack of have adverse impact on building conservation of materials and values.

Structural movement: permanent survey stations can be established independent of the site and readings taken on a regular basis to a set of permanent markers fixed onto the building surface using high precision total station survey instruments. As a rule of thumb, a monitoring system should be at least ten times more accurate than the lowest threshold.

To determine if building or parts of building are moving.
Materials: Surface erosion
Surface erosion: the surface can be mapped either using digital close range photogrammetry or laser scanning to establish a digital terrain model (dtm). This process can be repeated and quantitative analysis made possible using specialized software for depicting surface change. It would be essential to carry out accurate control measurements so that all dtmís could be georeferenced (overlapped precisely). To determine location and quantity of erosion of building materials.
Materials: Moisture content

Moisture meters

Moisture meters are used to measure the percentage of water in a given substance. This information can be used to determine if the material is ready for use, unexpectedly wet or dry, or otherwise in need of further inspection. Wood and paper products are very sensitive to their moiture content.
Movement: Cracks

Plaster patch, glass plate & epoxy resin, 3-point brass pins survey


To determine if parts of building are still moving and in what direction.
Multiple information data gathering
There are now available a number of ‘matchbox’ sized data loggers. These are small enough to be positioned inconspicuously within buildings and are accurate and user friendly. They generally measure temperature, relative humidity (RH), dew point, vapour pressure, lux, ultra violet (UV) and timber moisture content. To gather data on various environmental conditions with a single sensor.
Past conservation treatments
Various types of laboratory and site tests and observations. To determine the effectiveness of past treatments.
Building Code inspectors, architects, engineers. To determine public safety measures in case of emergencies (fire, water, earthquakes, riots, demonstrations).
Local police, security experts, reports from site guards To determine level of protection of building and contents.
Building Structure Resistograph To determine deterioration of structural timber elements.
Surface temperature variations
Temperature sensors To determine the level of protection of the building and its contents.
Ultra Violet levels
UV sensors To determine if levels will affect textiles, paintings, colours.
Water infiltrations
Visual observations To prepare remedial actions.
Dollars in craft sales
Interview craft shop owners To prepare remedial actions
Dollars spent by population in the area
National Statistics To determine economic impact of monument and site on local economy.
Dollars spent by tourists
Interview local businesses, visitor surveys To determine economic impact of monument and site on local economy over time.
Grants received from outside sources
Survey businesses, organizations To determine contribution by international community to monument.
Amount of education literature produced
Number of publications, number of copies sold, Dept. Of tourism, publishers To assess level of population`s understanding.
Education Number of students taught Interview with school children and principals To assess level of studentís understanding; they are the next generation who will have to care for it.
Environment Acid rain levels   Calcareous materials and metals are especially affected by acid rain. Monitoring levels will help to determine acceptable threshold.
Environment Changes Aerial photography & aerial remote sensing, color & infrared photography To monitor & mitigate environmental changes, vegetation type, variety and health and water pollution.
Environment Dust pollution Dust deposition sensors, airborne particulate sensors (light) Top determine what and how much dust is deposited and to determine how best to mitigate if a problem arises.
Environment Light Photometric sensors, Blue wool standard, solar radiation sensors (pyrometer) To determine the total amount of visible light affecting the fading of certain materials, the total amount of solar energy heating a building or materials.
Environment Noise levels Decibelmeter To determine levels of noise from traffic, mousic, crowds, vendors, restaurants, business establishments and plan remediation to problems.
Environment Ozone levels O3 Analyzer To determine levels of this color fading oxidant.
Environment Pollution levels and pollutants Various technologies To determine the presence and level of pollutants that may affect the monument or the people.
Environment Seismic activity Seismic sensors, national & international statistics and data To determine if conditions are below established thresholds.
Environment Smells HS detectors To improve quality of visitor experience.
Soil moisture
Soil moisture sensors To determine level of moisture at building foundations.
Environment Sulphur dioxide Pulsed Fluorescence SO2 analyser To determine levels and causes of sulphur dioxide, that causes deterioration of stone and metals.
Environment Waste management & disposal Visual observations, waste disposal staff or company, site manager To manage visual appearance of building & site, cleanliness, visitor experience.
Number of current jobs in area
National tourism statistics To be able to compare from year to year and assess impact of monument on job creation.
Number of dollars spent in creating quality jobs
Survey local businesses (for full time jobs, well paid, good working conditions etc.) To assess impact of monument on creation of quality jobs.
Number of jobs created over time
National tourism statistics To assess impact of monument on job creation.
Number of jobs for development
Regional / Local statistics To assess impact of monument on job creation.
Number of jobs for servicing
Regional / Local statistics To assess impact of monument on job creation.
Lime plaster deterioration
Photographic survey, visual inspections for cracks, stains, detachments, loss, salts To determine maintenance program, replacements, repair & conservation techniques.
Mortar deterioration (bedding)
Core sampling, core wetness sensors To determine structural stability & integrity, conservation & injection techniques.
Mortar deterioration (pointing)
Survey cracks, loss, adhesion, cohesion, tests for characterization, resistance water absorption, vapour transmission To determine maintenance program, replacements, repair & conservation techniques.
Stone accretion deposits
Visual observations, chemical analysis, photography TYo determine maintenance program & cleaning techniques.
Stone corrosion of anchors
Radiography To determine when and how to intervene.
Stone discoloration
Photos, photos with color scale To select tests and test areas to determine causes of discoloration.
Stone preservatives & consolidents
Tests to determine levels of water repellence, waterproofing, vapour transmission, mechanical resistance To determine maintenance program, replacements, repair & conservation techniques.
Stone staining
Observation, colour photography To determine cause and cleaning method
Stone water absorption
Rilem tube & lab water absorption tests To determine stone mechanical resistance especially to freeze-thaw cycles, water absorption may introduce salts in the stones.
Stone weather resistance
Sodium sulphate crystallization test, thin sections analysis To determine level of stone resistance to weather.
Amount of coverage internationally
Square cm of international newspaper or magazine articles and hours of foreign radio or TV. Content should be analyzed by academics in literature To determine quantity & quality of media coverage, perceptions by international visitors, protection of site values.
Amount of coverage nationally
Square cm of national newspaper or magazine articles and hours of national & local radio or TV. Content should be analyzed by academics in literature. To determine quantity & quality of media coverage, perceptions by national & local visitors, protection of site values.
Meteorology Amount of precipitation / period of time    
Meteorology Floods & flash flooding National statistics Flash flooding carries with it debris, soils and stone that erode and crack monuments.
Meteorology Levels of relative humidity RH sensors When RH is higher than 70%, this is optimal condition for growth of micro-organisms. To determine level of comfort for visitors.
Meteorology Variations in temperature / period of time Thermometers To determine impact of visitors, building materials, fauna and flora.
Meteorology Wind amount & dfirection / period of time Various wind tracking instruments To determine wind direction and intensity over time. Dominant winds affect rate of wetness & dryness of materials, wind borne particles may erode materials.
Visitors statistics, interview site personnel and maintenance crews To determine maximum number of visitors


Site observations, photography, mapping techniques To identify potential flodding areas or damage to structures and buildings' foundations
Aerial photography  
Use and occupation by people and animals
Visual observation Manage site use
Type of vegetation
Visual observation, historical photos Roots and branches may damage monuments, keep moisture in areas that should be dry.
Visual intrusions
Photographic records, visual observation To manage incompatible developments, litter, special pollution, signage.
Cultural values (shifts, changes etc.)
Surveys, analysis of media and publications To manage changes in traditional life ways, crime.
Social impacts
Surveys To manage impacts unacceptable to the local population and sustain those that are favourable and welcomed.
Number and type of vehicles / period of time
Highway Dept., local police Dept. (license plates identification), Surveys To determine volume of vehicles during specific periods, capacity for traffic and parking, who parks where, levels of pollution, to plan for additional roads & parking lots, to better manage vehicle traffic.
Hotel occupancy, airline, Dept. Of Tourism, tourism center records, government statistics, visitor surveys, ticket sales To support funding request, annual statistics, relative importance of site.
Number in specific areas of site
Counting on site, electronic sensors at entrances & strategic places To alert site management to degradation of the visitor experience due to overcrowding, to provide statistics needed to plan for visitor services within site, to alert managers to potential degradation of material fabric that might be reduced by heavy visitor traffic in a given area.
Number of days tourists spend in the area
Survey local businesses, hotels, transport agencies, regional statistics bureau To extend visitor stay in the region.
Airlines, trains, car rental agencies, origin maps in various businesses To support investments in marketing strategy.
Register books, hotels, restaurants To support investments in marketing strategy, to plan for new resources and facilities.
Volunteers Number of volunteers hours Number of meetings and participants To determine amount of support from population and interest in protecting and sharing this resource.
Volunteers Number of volunteers involved in programs Contact local groups and associations To determine amount of support from population and interest in protecting and sharing this resource.