Monitoring moisture condition

Key monitoring levels

• Level 1 – mainly visual but also using other senses – building/human interactive.
• Level 2 – using electronic moisture meters (EMM), in resistance and capacitance modes.
• Level 3 – using EMM accessories:
  • non-invasive; and/or
  • invasive.
• Level 4 – using carbide meters (sometimes gravimetric method (oven drying)).
• Level 5 – using sophisticated data logging and wireless equipment and, where required, opening up of elements of the building.

House surveyors mainly use level 1–2 techniques, flooring contractors and drying contractors chiefly use level 1–3 techniques. Level 4 and 5 techniques are used by some house surveyors to diagnose condensation problems, particularly in social housing when disputes need to be resolved between the property manager and occupier. Level 5 methods are used by specialist environmental consultants to solve complex dampness problems.

When we visit a site to check building condition we use all our senses to assess change. We also interact with occupiers and find out key information regarding not only the building itself, but how occupiers and users are experiencing and reacting to it.

Key monitoring procedures

• Establishing key aims of monitoring.
• Initial assessment of moisture condition in the building materials, indoor and outdoor air.
• Key decisions on methodology – what, where and how to monitor (note there may be physical access issues to take into consideration).
• Installing monitoring stations or development of monitoring positions.
• Taking moisture condition readings at intervals (as a basic rule, results from 3 monitoring visits would be needed to establish any kind of definable trend; that is, that any part of the building is becoming wetter or drier. Two site visits producing declining damp readings might not be conclusive enough. Occupiers’ permissions may limit the number of times you can return to a property).
• Analysis of readings and information collecting.
• Fine tuning of remediation in the light of readings collected.
• Evaluation.

Many of the monitoring examples featured in this chapter are in a drying scenario, following flood damage.

Any survey you carry out on any building could potentially become part of a monitoring exercise – as you may later return to the property and compare what you saw and noted on day X to what you see and note on the subsequent visit, day Y.