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THERMAL SCANNING


Thermal Scanning is an optional, add-on service that has literally changed the way homes are inspected today.


What is Thermal Scanning?

It is much easier to show you what it is rather than explain it.  This link allows you to view a sample home interior through the eyes of infrared.  It provides an excellent example of what can be viewed in your new home (provided by Flir Systems Inc.).

Thermal Scanning Demonstration


How is Thermal Scanning integrated into my home inspection?

There are many things that infrared can detect, but at most homes, there are 3 primary issues that we tend to find:

#1 Wetness - The first is wetness behind finished walls and ceilings.  During this portion of the thermal scan, water is run through all of the fixtures for approximately 30 minutes.  The hope is that if there is a drip / leak anywhere, it will have had time to dampen the back side of the finished wall / ceiling areas prior to scanning.

One of the most common sources of leakage I find during my inspections is at bathtub overflow drains.



In most of these situations, the homeowner is completely unaware that a problem exists and the reason for this is that leakage only occurs if the bathtub is filled above the overflow drain height (water must enter the overflow drain in order for the leakage to occur). Since this situation rarely occurs at many homes, the problem goes undetected.

In some cases, overflow drains can be viewed from plumbing access panels.



If there is no access panel, I can use infrared to view the area below the bathtub.  Many times, I find evidence of active leakage.

In this example, wetness was found on the furnace room ceiling - below the bathtub area.



There was no moisture stain on the ceiling, but infrared detected wetness (dark area at center of screen).



This example shows a dining room ceiling area that appears fine. There are no moisture stains.



But the thermal image clearly shows that there is active wetness at this location. In this case, the utility room was located above this area and it was determined that the water softener was leaking. The ceiling had been recently painted, but portions of the drywal should also have been replaced.



This image shows a normal looking exterior wall. A lower level bathroom exists on the opposite side.
 





After running the shower for approximately 15 minutes, a small amount of moisture was detected at the exterior stucco wall - exiting one of the wall cracks.

The thermal image of this location revealed a very large dark / cold area directly behind the shower wall, which suggested that moisture had been leaking through the shower walls for a long period of time. This is a situation where mold and mildew will likely be found.



This shower stall below was recently installed.  The home was purchased by an investor who had recently finished the basement, in prparation to "flip" the home for resale.



There was no evidence of problems in the basement



After running the shower for several minutes, wetness was detected at the base of the family room wall, using the infrared camera.  The exact source of this leak was not determined, but repairs were made prior to my client moving in......thanks to infrared.




#2 Missing Insulation - The next issue we look for is missing insulation behind finished wall / ceiling areas.  It is common to find some areas where insulation has settled












The infrared image below shows what missing insulation looks like during summer months - when the outdoor temperature is warmer than the indoor temperature.



In some cases, settled insulation can be the result of past, or current ice dam activity.

This is an image of a wall in an older home, where ice dam activity had been occurring.



In other cases, we find areas where the insulation was simply omitted.
In the example below, an obvious void was found in the ceiling insulation.  This was a home that was just constructed.



The dark area in the infrared image shows where the insulation is missing



Here is another void - found in a master bedroom area.



The image below shows a section of kitchen ceiling that was not insulated.  The house was only 5 years old and there was no access to the small attic space above this portion of the kitchen ceiling.  This would never have been discovered without the use of infrared.

Heavy ice dam activity would likely have occurred above this area in the winter time.


#3  Heat Loss - The primary thing we are looking for in the attic is evidence of air leakage into the attic (otherwise known as, "thermal bypasses).  Thermal bypasses are the number one source of ice dams.  With the use of our infrared camera, we can help locate the air leaks and can also provide recommendations for properly sealing them.



This image clearly shows heat loss at the base of this exhaust flue.



When the insulation was pulled back, the large gap was obvious.



Bath vents are also leakage sources - both at the fan housing and also where the vent passes through the roof.



Gaps are very common at the base of plumbing vents.



Here you can see the heat loss at the base of the pipe.  There are multiple ways to seal openings like these, but most people will use spray foam insulation.



Recessed light are a major contributor to heat loss into the attic.  Some types are more problematic than others.



Here you can see the heat loss from the back side of this recessed fixture.



If air ducts pass through the attic level ceiling, they should be properly sealed at their ceiling penetrations.

Soffit areas in kitchen and bathroom areas are also often sources of heat loss.  In older homes, builders often did not install drywall on the back side of the soffit.  This allows warm air to move up the walls into the dropped area, and out the opening above, into the attic space.



The dark colors show where insulation is lacking.






Gaps at the base of masonry chimneys are also common.



In older homes, gaps often exist at the tops of the walls (referred to as "balloon framing"). Wood, plywood, rigid board insulation, or gypsum board can be cut to fit over these openings and then caulked into place.




What else can thermal scanning find?

#4  Overheating Electrical - While electrical systems cannot be completely evaluated during our cursory evaluations, we can try to look for overheating switches, outlets and circuits.  Sometimes we do find them.



These images show hot wires behind a finished wall.  This is a condition that needs to be repaired by an electrician and it would go completely undetected without the aid of a thermal imaging camera.



The draft fan on this furnace was overheating, and may not have been noticed without the use of infrared.




#5  Pet Stains - Pet stains can also sometimes be detected.  In this case, the pet stained carpet was obvious.




#6 Rodent Activity - In some cases, tunnels can be found behind finished walls.



The dark areas behind this finished basement bedroom wall are evidence of rodent tunnels and suggest that mice have been nesting in this area.











It is possible that dead mice may also exist at locations like these.


#7 Concealed Heating Registers - When homes are modified over time, it is possible (as unlikely as it may seem), for heating supply registers to be concealed.

In the example below, there was no visible heat source in the attic level bedroom.



However, the infrared camera located a heat source behind a finished wall, which suggested to me that a supply register was simply covered.  In addition to this being a huge waste of energy, this would also create ice dam problems in the winter.





#8 Air leakage - Without performing a blower door test, air leakage is difficult to locate, so we do not claim to find air leaks.  However, some leaks may still be detectable during our evaluation, like this one - at a window.

 


#9 Structural Verification - Proper placement of structural members (i.e. headers) can be identified.






#10 - Locate Radiant Floor Heat - Infrared is the only real way to evaluate in-floor, radiant heat.







Radiant floor heat should spaced at least 2".  This particular example is a potential overheating concern.



Radiant floor heat should be at least 6" away from toilet wax seals to prevent the seal from melting.



These coils were not spaced consistently - a sure sign of an amateur install.



This client did not know how this condo was heated.  We found heating coils covering almost every square inch of the ceiling.




#11 Locate Leaks at Radiators - Infrared can also check for leakage at covered radiators (helpful if the covers are difficult to remove)




Services Offered
Thermal Scanning is used at all homes - in high concerning areas only.  The most frequent area where it is used is on finished ceiling areas, below bathrooms (leaks are often found below bathtubs or toilets with infrared).  "Concerning areas" are left to the judgement of the inspector and this is based on experience (infrared was first used in 2004).

If you want your entire home scanned, this will be an additional fee, added to your standard home inspection.


#1 Pre-Purchase Thermal Scan

Click here for pre-purchase thermal scanning fees

#2 Existing Homeowner & Seller Scans
Thermal scanning is also available to sellers and existing home owners.  The fees for this service are as follows:

Whole House Scan $295.00

Single Component Scan (one area of home) $175


Limitations of Thermal Scanning

Thermal scanning is a very effective tool that helps greatly improve the quality of your home inspection.  However, there are limitations to this service and it is important to understand that thermal imaging does not completely remove the risks of concealed damage.

Listed below are some of the areas where thermal imaging can be used and the limitations of each:

Moisture Detection in Walls and Ceilings - Thermal imaging helps to identify water damage in walls, floors, and ceilings. The most common hope from buyers is that thermal imaging is the cure-all for moisture detection in exterior walls.  Unfortunately, this is also the area where infrared (thermal scanning) is the least reliable.  Why?  Areas like these may not be detectable if they have been dry for an extended period of time. Moisture is especially difficult to detect from the exterior of the home, due to things like radiant heat from the sun, which can cause "thermal blindness", preventing any evaluation of the surfaces.  

 To have any chance of finding moisture in exterior walls, there must be a variance in temperature established between indoors and outdoors.  This is no problem during the winter, or hot summer months, but during the other seasons, it often requires the aid of the HVAC system.  This is simply not possible at times (particularly when outdoor temperatures are in the 70's).

Plumbing Inspections - Leakage from plumbing is much easier to find.  Thermal imaging greatly increases our inspection for leakage below plumbing fixtures, yet even thermal imaging cannot guarantee that all leaks, or drips will be found.

Also note: Wetness behind certain types of materials can be challenging to detect (i.e. concrete, or wood walls, including wood paneling).

Electrical Inspections - Thermal imaging can detect hot spots in the electrical system that are not visible to the naked eye (e.g. overheating circuit breakers, or circuits). However, since a load is not applied to all of the circuits during a home inspection, it is possible for some things to go unnoticed (circuits must be hot to detect problems).

Air Leakage - If air leakage is a primary concern of yours, you really need to have a blower door test performed, which is included with the purchase of an "energy audit".  Unless the air pressure is removed from the home, there simply is no way to guarantee that air leaks will be visible - even to a seasoned thermographer.

Flat Roof Inspections - Thermal imaging can be used to detect the precise location of flat roof leaks.  Again, if the area has been dry for an extended period of time, the leakage may not be visible. The obvious benefit here is that the location of active leaks can be identified so that a contractor can more easily determine what repair options you have - saving time and money.  Of course, complete replacement is always recommended when the roof is old.

Stucco & EIFS Inspections - Suburban Home Inspections does not perform stucco / EIFS moisture tests. It is possible to locate moisture problems in stucco walls and this usually appears as heat anomalies. However, there are many limitations, such as sun reflection, which greatly reduce the effectiveness for locating moisture in stucco walls. Ultimately, the best way to find moisture problems is to have an intrusive test performed and this requires a moisture specialist.  We are happy to refer you to a qualified specialist if needed.

The bottom line is that there is no guarantee, but based on my past experiences, you are far better off using thermal scanning than not.