This method of building inspection makes it possible to identify the source of certain problems without even having to open the walls and go through every nook and cranny of a house. As we can see on this picture, infrared cameras can even detect hidden problems in a house’s cladding.

What the cameras can spot:

• A lack of waterproofing or thermal insulation in a house’s exterior membrane
• Presence of water infiltration in the walls, in the foundation or on the roof
• Presence of condensation in the walls
• Heat loss from the heating system (leakage in some heating systems)
• etc.

What is thermography?

It is a technique that records a temperature on an object or material using infrared rays. Infrared cameras record the temperature on certain surfaces at different points. They make it possible to reproduce the cartographic images of the building as well as the recorded measurements, also known as “thermograms”.

A colour code is used to understand the temperatures recorded by the cameras. Cold spots will be represented by cold colours: green, blue, purple and even black. On the contrary, the hot spots on the surface of an element will be represented by the heat intensity. These colours can vary from yellow to orange, red and then white. Recording very hot or very cold surface points can indicate an anomaly for the building.

For example, the thermograph can read the inside wall of your house, and you will be able to see that part of the wall completely blue. This could indicate a lack of thermal insulation in winter. If the same section of the wall was captured from the outside, we would be able to see warm colors due to the heat loss.

How is the data interpreted?

The task of analyzing a thermogram is complex. To interpret the data, several factors must be taken into consideration. To properly understand the colours obtained, one must take into account the radiation characteristics of the materials amongst other things. For example, brick and aluminum do not capture and diffuse heat in the same way then other materials.

When a technician uses a blower door to monitor the indoor air pressure of a building, the information obtained will be largely influenced by the atmospheric conditions at the time of the inspection. In these situations:

• A difference of 10°C or more between the interior and exterior must be taken into account when inspecting the building envelope. In this context, the winter period is ideal. *Infrared cameras that are several years old need a bigger gap because of their less advanced technologies.
• For the exterior inspection, it must be done in good weather conditions. It should be early in the morning or a few hours after sunset. Rain and sun alter the temperatures captured on the surfaces.

Who can do this kind of analysis?

Although some infrared cameras are sold on the internet, you cannot impersonate a thermography inspector. We must be rigorous in our analyses and have the necessary skills to obtain the right results. Images must be obtained and interpreted by certified experts. A Level 1 certification is required for the use of the infrared camera and a Level 2 certification is required for report writing.

What happens after the thermographic inspection? The report

When the camera inspection is complete, the inspector must analyze the data obtained. The inspector will then provide a detailed report, which contains:

• All infrared and digital photos showing the problems observed
• Explanations or construction details observed
• Diagrams illustrating the problem as well as the corrections to be made
• An explanation of the proposed correction methods and what they entail

In the report, we should also find a description of the ambient conditions during the inspection as well as the parameters for capturing the images: calibration of temperatures, distance of the device from the observed surfaces, emissivity of the materials (the ability of the materials to absorb and re-emit its energy through radiation), etc.

Finally, the identity of the inspector and his qualifications must be present on the report.

How much does a thermographic analysis cost?

The cost may differ depending on the scope of the work that must be done and the extent of the surfaces to be analyzed. The fees to inspect a single wall are not the same as the inspection of a complete house. You can request a quote from experts in order to ask your questions as well as adjust your initial request if necessary.