Best Time for Thermal Imaging Inspections

Hi Everyone, (This is specific to thermographers)

Recently I had an email sent in with an interesting question from an inspector. Here is the questions below, with my response below.

 

QUESTION:

Hi Dean,

Based on TV and U-Tube videos  it doesn’t appear to be too difficult to find moisture in your country these days. To find moisture under normal conditions, however, seems to be much more difficult.

Your website is full of moisture examples and at one time you even offered “no fee if no moisture is found”.
 I for one haven’t been able to find moisture anywhere yet and am wondering whether I overlook something, whether there is more to know where and how to look for or whether it is a result of a different climate, different construction methods, etc.

With all of your experience, why not summarize it in a course manual or loose leaf collection for sale. Add a paragraph on moisture meters and how to use them. I have a Tramex and am still not sure / confident as to how to use it properly. The manual which came with it was piss poor. It has three scales,

“Wood, Timber”
“Drywall, Roofing”, whatever “Roofing” is
“Plaster, Brick”

What if you have mixed materials? Plaster on plywood? What if you are looking at something you don’t know what it is? You don’t know what is behind the wall paper or underneath the flooring? Or something which is not listed?

I found out “false positive” the hard way, i.e. embarrassing. A metal forced air duct in an outside wall. IR showed “cold” from the bottom up but only because of reduced thickness of the insulation. The alarm of the moisture meter went off but not because of moisture but because of the metal duct, i.e. false positive.

Another example, an apparent circular wet spot at the ceiling but no moisture alarm. The ceiling was rough ornamental stucco. So I wasn’t sure whether there was no moisture or whether the contact was insufficient.

I trust you have dozens of examples you may be able to share with the rest of us.

Address the three sources of moisture, infiltration, condensation, faulty plumbing. Anything else?
Point out the best time to do the inspections. It would be my understanding that condensation will not show while condensation is taking place. You need evaporation to cool the wet area and both evaporation and condensation do not take place simultaneously.

BTW, I am in Alberta, Canada, a relatively “dry” place.
Looking forward to your comments with interest,

 

ANSWER:

Hi…,

Thanks for the email.

This isn’t something I would write a course about because there are just so many variables in building construction between countries which effect moisture ingress into building envelopes. Also, different countries have different building codes… eg. They changed the building code where I live to say you didn’t need to build with cavity system between the timber framing and outside external cladding.

What happened in many homes here is that the walls can’t breathe, therefore you get condensation inside the wall rotting away framing without any leaks at all (And if it does leak the water can’t get out). Throw in a few other design faults that were approved here and it’s become a MAJOR issue. See here: http://findaleak.co.nz/9-common-signs-of-leaky-home.html . This is called the ‘leaky building syndrome’ and I believe you have a this issue in Canada also in some regions.

Drilling a small hole into the lining of walls and sticking an endoscopic camera and humidity reader into the wall to get the ‘true’ result is the quickest way, as a thermal imaging camera will only detect one half of the story.

You are correct that there needs to be more application specific courses, and I’m not sure why there isn’t one to address your concerns.

Have you contacted Greg at Stocktoninfrared.com ? He would most likely send you a paper on it.

Regarding the best inspection time, just take a heater with you and warm up the room… that takes care of the infrared side. Have a non-invasive and invasive moisture meter and humidity reader etc. It really does require a combo of tools to get it right!

Let me know how you go, and if he doesn’t have something then maybe I’ll put a small guide together.

Inspecting isn’t rocket science… you just need to go through the motions of the inspection and have the correct tools at hand to get yourself a confirmed result. If an enquiry is outside of my knowledge base then I simply don’t inspect the property.

Hope this helps.