How a Thermal Imaging Inspection Should Be Carried Out - and What Is Often Missed

There’s a bit of a misconception around thermal imaging that it’s just a case of turning up, pointing a camera at a wall, and seeing what’s going on.

That’s probably the easiest way to get it very, very wrong.

A proper inspection starts before the camera even comes out. You’re already thinking about how the building is likely to behave, what conditions have been leading up to the inspection, and whether you’re even going to get meaningful information on the day.

If those things aren’t considered, you’re not working with much — no matter how good the camera is.

You’re reading behaviour, not taking pictures

A thermal image on its own doesn’t tell you much.

It’s just showing how surfaces are reacting at that moment. What matters is understanding why they’re reacting that way.

A cooler area might suggest moisture — or it might just be airflow. A warmer section might be insulation-related — or something else entirely.

The point is, nothing should be taken at face value.

You’re constantly filtering what you’re seeing against:

• how the building is constructed

• what materials are involved

• what the recent conditions have been

• and whether the pattern actually makes sense

That’s where most of the work is.

The building dictates how you approach it

No two houses behave the same, especially in Christchurch.

You’ll get properties where:

• one part is original

• another has been repaired post-earthquake

• another section has been reclad or altered

Those sections don’t respond uniformly. So if you approach the whole building as if it should behave consistently, you’ll misread it.

Instead, you’re adjusting constantly — moving through areas differently depending on what you’re dealing with.

That’s something you only really get comfortable with after seeing a lot of variation.

Conditions can make or break the result

This is where things often fall over.

If the temperature difference isn’t there, or the building has been exposed to sun or wind in a certain way, what you see can be muted or misleading.

Sometimes you still get useful information. Sometimes you don’t.

Knowing the difference is important, because there’s a temptation to produce a result regardless — even when the conditions aren’t giving you much to work with.

That’s where overconfidence creeps in.

Where less experienced operators come unstuck

It’s usually not the equipment.

It’s how quickly conclusions are drawn.

Common issues tend to be:

• assuming every anomaly is moisture

• not questioning what else could be influencing the pattern

• skipping any form of cross-checking

• treating the image as an answer instead of a clue

That’s how you end up either missing something completely, or flagging something that isn’t actually a problem.

The difference is in restraint

A good inspection isn’t about finding something at all costs.

It’s about knowing when something is worth pursuing further — and when it isn’t.

That means being comfortable saying:

• this needs follow-up

• this is inconclusive

• this doesn’t line up with a defect

That level of restraint is what keeps the process reliable.

What this means in practice

When it’s done properly, thermal imaging helps narrow things down.

It gives direction. It reduces guesswork. It allows the next step — whether that’s a builder, plumber, or further investigation — to be more targeted.

When it’s done poorly, it either adds noise or gives false confidence.

Where the real value sits

It’s not in the camera, and it’s not in the image.

It’s in how the information is handled.

That’s the part people don’t see — but it’s the part that actually matters.