Bruce Symon Realsure Director
Non-invasive moisture detection devices and other tools are widely used by Accredited Building Surveyors to help build up a picture of any problems with a property.
However, many people don’t fully understand the abilities – and the limitations – of such tools, and there are many myths and misconceptions about their use, especially thermal imaging cameras.
Basically, such tools are only an asset when in the hands of an accredited building surveyor. Skills, knowledge, and surveying processes are the predominant factors when it comes to assessing whether there are or may be issued with a property. This is particularly relevant for weather tightness risks and related issues such as leaky buildings.
A competent building surveyor will use a moisture detection tool to assist in assessing indicators of moisture ingress.
Generally, this will be used around joinery – as that’s an obvious breach in the cladding – wet areas, places where there are visual indicators of possible moisture issues, and accessible exterior moisture ‘risk’ areas.
Non-invasive moisture meters are the most commonly used tool. These determine the moisture content up to a depth of 40mm from the surface dependent on the meter being used.
This equipment only provides an indicator and, in non-invasive mode, their results are not conclusive. However, in the hands of a building surveyor, they are a valuable tool to provide further evidence of possible moisture ingress.
This means it is critical that they are used by an operator who has the training, skills, and experience to be able to put all the evidence together and assess it to provide an accurate account of the findings.
Equally, just because a moisture detection tool does not indicate moisture, it does not mean the property is not suffering from moisture ingress issues. It might be that there has been a dry spell or the defect has not yet manifested itself enough to be detectable.
Most myths and misconceptions surround the use of thermal imaging cameras. These certainly are not the ‘ultimate leaky home detector’ some may have presented them as. They don’t detect moisture and they certainly cannot see through walls.
Basically, they detect thermal radiation that provides a picture indicating surface temperature variations. Colder areas may indicate the presence of moisture or leaks that require further checking with a moisture meter.
Essentially they are just another tool that can be useful in the hands of a good building surveyor.
Using such devices other than in conjunction with the appropriate survey by a building surveyor is very risky. Used alone they will not identify the risks, defects, and issues that these experts can.
A thermal imaging camera might give a property a “clean bill of health” but that doesn’t mean there are no problems. For various reasons, they may have been undetectable by that tool on that day.
The best and safest way to ascertain the condition of a property is to call upon the services of an Accredited Building Surveyor. They are accredited to a process that requires them to demonstrate their compliance with all requirements of NZ Standards for Property inspections NZS4306:2005 and have been found to be competent and knowledgeable to undertake them.
Within their arsenal of tools, they will have a non-invasive moisture meter for the detection of moisture indicators and some may also offer the additional option of a thermal imaging camera. In truth, while these cameras have been used in the electrical and industrial fields for many years, their reliability and accuracy as a tool to detect “leaky Buildings” are still being assessed by the industry. It would seem they will have a place, particularly around the energy efficiency of a home. However, their use as a detection tool is limited and part of the limitation is that they should only be used in conjunction with a building surveyor to ensure the full accurate picture is obtained.