Lets get it on

[Roy D. Cooke, Sr]

Great discussion .
Brings back what we where taught and gets us all thinking ,
Thanks to all..... Cookie
The instructor said to me less then 2 % of those who buy a camera take classes .
Now some I expect have Plant instruction as in our class 22 only 4 where Home Inspectors.
I wonder have all Home inspectors taken classes or Just the NACHI members ?

[William Warner]

Originally Posted by dandersen

Thank you Mr. Warner.

I was taught a method of determining the maximum Delta T by monitoring the temperature of the roof and the temperature of water in a container. In the morning you'll receive the greatest temperature difference as the roof begins to warm more rapidly than the water. At some point around midday, it is likely that the water temperature will match that of the roof temperature. Later in the evening the roof will cool more rapidly than the water. At some time late at night, just like at high noon the temperature of the roof and the water will equalize.

I suppose monitoring a container of water would help but seems a bit extreme than just understanding the thermal window. I was trained that flat roof inspections and EIFS inspections should be conducted in early morning or evening for the same reasons (thermal window). You are precisely correct about the thermal differences at the times of day. Water signatures will appear as a cool spot in the mornings and a warm spot in the evenings but may become "invisible" to the camera midday or late at night.

[William Warner]

Originally Posted by cbottger

Guys this was not a test I was surprised my self when the low temp showed up I was not actually scanning the roof was the wrong time of day especially with the water frozen. And yes my instructor did say the night time after radiation cooling takes place never scan a roof in the heat of the day. you are looking for evaporation of the water beneath the roof covering; water holds the heat longer and will show up.

I suspect part of it is indeed reflection from the sky and space but your image indicates a temp range from -12 to 28. There's some awfully cold objects up there on that roof. You don't indicate ambient temp or the lowest temp of the night before. The low temp is probably due to the thermal capacitance of water and also due to latent heat of fusion. Also understand that air movement at 10MPH a surface will lose 50% of its actual temp. The slightest breeze will reduce surface temps.

[William Warner]

Originally Posted by rcooke

Great discussion .
Brings back what we where taught and gets us all thinking ,
Thanks to all..... Cookie
The instructor said to me less then 2 % of those who buy a camera take classes .
Now some I expect have Plant instruction as in our class 22 only 4 where Home Inspectors.
I wonder have all Home inspectors taken classes or Just the NACHI members ?

WOW!
Spend that much money on a piece of equipment and not know how to use it or at minimum the science behind the technology!

[Peter C. Russell]

Originally Posted by dandersen

Attic door, colder in the attic than in the house.
Where is the hot spot coming from?


My reflection.

Dave, is that a reflection from the termination strip used on the carpeting?

[cbottger]

This home was a mess was called for imaging inside this home that I showed the pics above with the flat roof. Walls were cinder/concrete block, mold was growing behind vinyl wall paper that had already been removed and the laminate flooring had been pulled up. Water had been seeping upward out of the laminate flooring. Client wanted to determine source of water. Concrete slab floor had one hairline crack approximately 6 to 8 feet from where the water was noticed on the floor.

Mold was growing upward from the baseboard and at the top of the wall where it joins the ceiling.

Clients had closed on this home two week prior to my call and had decided to do some remodeling and this is what they discovered. Had been a home inspection prior to closing not by me.

The topography of the landscape surrounding this corner of the structure has the possibility of water intrusion at the bottom course of blocks. No cracks visible. pooling of water is visible at this exterior corner.

My determination was water penetration from two sources as the roof covering was in like new condition prior to closing. My thinking was water from a past roof leak and water intrusion at the bottom course of block or at least at floor level possibly from the crack slab.

We have a very high water table this year due to record breaking rain fall.

[cbottger]

More Pics same room in the corner

[Peter C. Russell]

Charlie, did you verify your findings with a moisture meter? and what was the level?

[John McKenna]

The reflection of the sky is always cold and distorted. We feel heat as it
(energy from sun) absorbs into our skin. The atmosphere lets the energy
pass through it (for the most part) and so the actual temperature of the sky
is much colder than what we feel. The reflection compounds the distortion.

BTW... no matter what your settings are, the actual image that you see
will still be the same on your camera. Your numbers may change, but
not the image. As an inspector, we compare the anomalies in the image
more than worry about the numbers. Chew on that.

[cbottger]

Originally Posted by prussell

Charlie, did you verify your findings with a moisture meter? and what was the level?

Yes Sir I did; owner had already dried as much water as they could absorb up and I still was reading 23%

[David P. Valley]

First of all....Professional results come from qualified individuals with the right equipment. I highly recommend Infrared training before attempting a flat roof inspection. Thermal cameras are amazing tools but they must be utilized correctly if you want to uncover moisture damage in your roof structure.

Another important factor as to "why" flat roof IR inspections are better off being performed at night or early in the morning.....

When there is sun glaring on the roof all day, flat roof areas (especially the roofs which contain ballast) will have a different thermographic color signature due to radiation of the stored energy from the daylight sunshine in the form of heat. This stored energy radiates as heat from these areas for a longer period of time. This stored temperarute will screw up your IR readings.

I personally would never attempt a roof inspection during the day, unless weather conditions warrant me to. I will schedule all my flat roof inspections after 5:00 PM. But you bet you're ****, I'd be on-site earlier for safety reasons. I'd want to see how I'm going to gain access to the roof and I want to walk the roof during daylight so I'm know what I'm getting into during darkness.

[cbottger]

Originally Posted by jmckenna1

The reflection of the sky is always cold and distorted. We feel heat as it
(energy from sun) absorbs into our skin. The atmosphere lets the energy
pass through it (for the most part) and so the actual temperature of the sky
is much colder than what we feel. The reflection compounds the distortion.

BTW... no matter what your settings are, the actual image that you see
will still be the same on your camera. Your numbers may change, but
not the image. As an inspector, we compare the anomalies in the image
more than worry about the numbers. Chew on that.

I would agree with that on moisture detection but not electrical.

[David P. Valley]

Originally Posted by cbottger

I would agree with that on moisture detection but not electrical.

Charley,

Electrical breakers and the buss bars will absolutely reflect images.

[cbottger]

Originally Posted by dvalley

Charley,

Electrical breakers and the buss bars will absolutely reflect images.

Very correct that is why we adjust for reflection because we are looking for the correct temp in the panels not just the image.

[David P. Valley]

Originally Posted by cbottger

Very correct that is why we adjust for reflection because we are looking for the correct temp in the panels not just the image.

Exactomungo