Residential moisture intrusion

Freedom Express Inspections and CMOR thermal infrared imaging locates moisture intrusion with a 3.6 Delta T being the difference between indoor and outdoor temperature. The ideal Delta T is 10 degrees or above. CMOR thermal imaging recommends for new construction with dry stack stone as exterior wall cladding having the exterior walls and all windows thermally scanned before the one year warranty expires.

If they would only listen.

Some are after the fact, Carl I have 5 ongoing law suits clients are finally waking up, going to do another follow up tomorrow

Good find.
10 deg. delta C or F?

This one will not be far behind.,2482.0.html

Problems with window installation/moisture barriers/lack of attention to flashing details.

I thought I read somewhere that (flashing) is suppose to exit the moisture to the exterior of the cladding/windows and such.

I see a Delta T of 7.8 and 8.0 respectively but am not sure where you get 10.0 as being perfect for detecting moisture intrusion?

Seems like a greater temperature difference between external and internal walls would help more unless it has something to do with your spectrum gauge and needing to expand or contract it.

Just guessing but seems logical.

The Delta T that Charley is referring to is the difference in temperature between the interior and exterior of the building. According to standards for infrared inspections of building envelopes, the minimum Delta T should be 10C (18F).

Using his skill, knowledge and proper equipment, Charley was able to locate these thermal exceptions with a much lower Delta T.

Nicely done!

Yes thanks for repeating what I said ,now maybe Charlie will have an actual answer.

Condo…his answer to your question was in his first post.


I don’t know anything about thermal, yet. Looking at the pics, what tells me this is moisture rather than air leakage? Thanks.

Moisture meter:D

You can not see a Delta T in the image what you are seeing is the average warmest and the average coolest temp. Delta T has nothing to do with the temp scale you see in the image. When doing moisture intrusion inspections I record on site what the exterior temp and humidity reading along with indoor temp amd humidity. Dont be giving my friend Tyler K a hard time he is a very nice guy.

Great I am sure he is now back to the subject as I told him thanks didn’t I?

Still asking and looking for a simple answer here of why a 10 degree temp is considered best for moisture intrusion discovery when logic dictates a higher differential would have more contrast.

I am sure we can take your word for it but just like when I tell clients weeps are needed it is often necessary to explain “why” ?

Thanks for your reply in advance.

Dale if he answered my question I would have said thank You.(See post above this one.)

Just for clarification - you need ideally a Delta T of 10C for air infiltration detection but why would you need a 10C Delta T for moisture intrusion? I believe that for moisture detection/intrusion the RH is the most important factor (important than Delta T). is that not correct?

Bob, you missed it. Charlie said “10° and above”. That’s what Dale is referring to.

Ah gotya.

It really depends on what you are doing and what thermal properties you are relying on to obtain meaningful results

For insulation and air leakage, you ideally want to achieve a 10C delta and thermal equilibrium which takes significant time to achieve. Your objective is to detect relative differences in the rate of heat migration through the thermal envelope. The greater the temperature difference, the faster heat migration occurs from the warmer to cooler areas giving you better contrast.

If you are doing flat roof inspections from the exterior, you typically want changing temperatures because the moisture is entrapped in the membrane, so you rely on differences in thermal capacitance. As the surface changes temperature the areas with water trapped within the membrane will change temperature at a different rate than areas without.

For moisture detection where evaporation is occurring, you don’t need a delta as evaporation is an endothermic process and will produce its own thermal contrast with the surrounding materials. Lower RH enhances evaporation, so you sir are correct.

If Delta T is difference in air temp between the interior and exterior then there must be other factors involved .
If doing a reading from inside and moisture has reached inside air temp then I see little bearing if the moisture temp has reached equilibrium with the interior.

Now if by delta T you are referring to temp difference between the moisture and the atmosphere around your cameras position I can comprehend that somewhat.

I did not see a reference to a Delta T 10C (18F) of moisture in the standards for infrared inspections of building envelopes, only for energy.
Did I miss something here?