Reuben's Home Inspection Blog


Stucco: Invasive Moisture Testing vs. Infrared Scanning


I’ve heard of home inspectors in Minnesota offering infrared scans on stucco homes as an attractive non-invasive alternative to standard invasive moisture testing.  Here at Structure Tech, we recently started offering infrared inspections, but stucco scans are something we will never offer.

Stucco CrackFirst, some info on stucco.Stucco homes in Minnesota built since the late 80′s or so have had a nasty history of catastrophic failures.  These stucco homes are more likely to have moisture instrusion problems than other types of homes, and the damage is usually far more serious. The City of Woodbury has an excellent position paper about Stucco in Residential Construction, which should be required reading for anyone buying a stucco home built during this time period.  In many cases, there are absolutely no visible signs of moisture instrusion.

Invasive Testing

My advice to anyone buying a newer stucco home in Minnesota is to have invasive moisture testing performed, which can be done from the interior or exterior (this blog isn’t going to be a discussion of the two methods, although that will be a great future topic).  Exterior testing is done by drilling holes and  sticking metal probes in to the wall to measure the moisture content of the wood. 

Invasive Stucco Testing
These holes get covered over with matching caulk after the work is done, and there is virtually no evidence that any work was ever done.  Interior testing is done in a similar manner, where holes are made inside the house and the moisture content of the wood is tested.  As long as the person doing the testing is good at it, the results that come from invasive moisture testing on stucco homes are highly reliable.

Infrared Scans on Stucco

IR Image of bad windowHaving a stucco home scanned with an infrared camera as an alternative to invasive moisture testing may sound like a great idea, as there are never any holes left in the walls with this testing method.  The problem is that infrared scans on stucco are unreliable.  Infrared cameras don’t see inside walls; they only show differences in temperature.

For example, the image at right is an infrared image of a window at a stucco home.  You can see a little green at the lower left corner of the window, which means this area is a little bit colder.  This was the worst area of moisture intrusion at the home, and an invasive moisture test found there was no wood to probe here; the wood had rotted away to nothing.

If only an infrared scan had been performed, what would the recommendation have been?  Tear the wall open?  Have an invasive test performed?  This was the only thermal anomoly shown on the entire house, but an invasive moisture test found unacceptable moisture levels in about a dozen other areas throughout the house.

Temperature differences may or may not equate to moisture intrusion.  Conversely, if there are no temperature differences in stucco, should one conclude that there is no moisture in the wall?  Absolutely not.  Infrared cameras are great at finding temperature differences, but not water. Infrared cameras can be used to give clues for places to perform invasive tests at best.

The bottom line is that infrared scans on stucco homes will give unreliable results and should not be considered an alternative to invasive moisture testing.  I’m a firm believer in invasive moisture testing on stucco homes, and I say this as someone with no financial interest in the matter.


Reuben Saltzman, Structure Tech Home Inspections


Comment balloon 35 commentsReuben Saltzman • February 22 2011 06:43AM


Hi,  Rueben. I don't offer the "thermal imaging on homes of any kind. While it may be a good practice. "Homesafe" which holds the PATENTS on how to inspect a home with thermal imaging has filed a ton of lawsuits to fine and stop the average home inspector from using thermal imaging without a licence from them. After a bunch of suits already. They have won all of them. I don't want to have to pay for offering a "thermal imaging" service. I will wait and see what happens next.

Clint McKie

Posted by Clint Mckie, Desert Sun Home, Comm. Inspection 1-575-706-5586 (Desert Sun Home, commercial Inspections) about 8 years ago

Clint - I've heard about Homesafe.  They have patents on a particular process, that's about it.  How do you know Homesafe has won their suits?

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Good morning Rueben. Great post on the difference. I had thought thermal imaging would have been more accurate. Also had no idea about Homesafe.

Posted by Randy Ostrander, Real Estate Broker, Serving Big Rapids and West Central MI (Lake and Lodge Realty LLC ) about 8 years ago


Some good information about the problems with stucco and moisture intrusion.


Posted by Richard Weisser, Richard Weisser Retired Real Estate Professional (Richard Weisser Realty) about 8 years ago

Good information.  It seems that Minnesota buyers do shy away from stucco, and I have run into problems before.

Posted by Chuck Carstensen, Minnesota Real Estate Expert (RE/MAX Results) about 8 years ago

There is no way that I would sell a property with this construction.  Most builders in my area discontinued this option early on when the homes that were rotting from the inside out made the news. 

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley,, MD & VA Homes and Real Estate) about 8 years ago

Randy - thanks.  Thermal imaging does an excellent job of finding temperature differences; unfortunately, that doesn't always mean moisture detection.

Richard - thanks.

Chuck - I can't say I blame them for being nervous.  Personally, I would avoid newer stucco homes, but I definitely wouldn't buy one without having invasive testing done first.

Lenn - I've found that stucco homes have become a far less popular option around here as well.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

My home inspector was one of the first ones to use infrared when doing inspections. I would advise any buyer for an additional $100 to use infrared when doing home inspections. Great information here

Posted by Harry F. D'Elia, Investor , Mentor, GRI, Radio, CIPS, REOs, ABR (Real Estate and Beyond, LLC) about 8 years ago

Thank you for the interesting artcile. I will definately keep this in mind the next time I sell a stucco home!

Posted by Rosalie Evans, The Evans Group, Sioux Falls, SD Homes For Sale (Meritus Group Real Estate) about 8 years ago

Harry - that's about the same thing that we charge to add IR scanning to a home inspection.  I think it's a great additional service for home inspectors.

Rosalie - thanks for reading.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Reuben, this is an interesting post. I agree, it looks like the invasive method is the only real way to find any moisture. The infrared method may give a false sense of security. Good info!

Posted by Michael Setunsky, Your Commercial Real Estate Link to Northern VA about 8 years ago

Stucco is an extremely good exterior covering, especially in dry climates. However, it has to be installed properly. Stucco is about all we have out here – low-end homes, high-end homes, commercial buildings, skyscrapers, etc. Stucco, stucco, stucco.

If you have problems with stucco up there, it’s probably because they didn’t install it properly.

Also, invasive moisture testing is so yesterday. With the advent of computer technology that gives us smart phones and other such devices, there are many non-invasive moisture meters on the market. I have had great success with the Tramex moisture meters. Been using one since 2001, although it was recently stolen. I paid something like $500 for it back then.

Yesterday I got my replacement, the Tramex Moisture Encounter Plus. I’ve already tested it on some setups that I created, and it’s excellent! Cost with California discount and California tax: $343

Posted by Not a real person about 8 years ago

In our dry climate stucco performs great.  Plumbing leaks and missing insulation are the best uses for infrared here.

Posted by Loren Green, Phoenix Home Inspector & Designer (Greens Home Design L.L.C.) about 8 years ago

Stucco doesn’t hold up well here in the Pocono’s but invasive testing practices stand even a lesser chance. Homeowners will quote that a home inspection by definition in a non-evasive examination. I’m afraid that around here infrared is going to remain the preferred method of inspection. 

Posted by Johnathan R. Therriault, Inspecting the Pocono's, one house at a time. (JTHIS-Professional Home Inspection Team ) about 8 years ago

Reuben are you talking about systhetic stucco or stucco?

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 8 years ago

Having spent the first 35 years of my life in Minnesota (can't wait for the Twins season to get going), and then having moved to the Southwest, I was interested in the extensive use of stucco here in the SW and was very curious as to its introduction and somewhat prevalent use in MN over the past 15-20 years.  Everything I learned about stucco is that it is an ideal exterior material in dry climates (which MN or the upper midwest would never be thought of as "dry"). 

I convinced my parents to avoid a home with a stucco exterior when they were looking to downsize simply because of the issues reported (not just in MN) of stucco/moisture issues with that material.  I'm sure, installed properly, stucco might be compatible with more moist environments, but I don't hold out a great deal of hope it will be installed properly (I remember the installation issues involved with the EIFS product back in the 90s).  Installed correctly, it worked as advertised.  Problem was only about 5-10% of the installations were done correctly.


Posted by Craig Frazer, Real Estate, RE/MAX Metro, Davis & Salt Lake County about 8 years ago

I would have to disagree with you in part. IR is a good tool to use, but anything that appears suspicious should always be checked with a moisture meter. This applies to all IR scanning for buildings. The invasive method should be used with IR scanning.

The one thing you don't mention about IR, and the reason I feel it has not fully taken off, is that proper conditions must be present for good scanning results. It is vitally important that the thermographer consider when the best time and conditions will exist to obtain good information from an IR scan. I believe this most important aspect of infrared evaluations is ofter not taken into account.

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) about 8 years ago

Hi Reuben, like Charles & Craig above, I am wondering if this is stucco or exterior finishing and insulation system (EFIS or synthetic stucco).  True stucco, installed correctly, has been found to a reliable product in the southeast.  EIFS has not because of installation problems which were predominant. 

Posted by Dale Ganfield about 8 years ago

I remember the stucco from like the 1920's and it is nothing like what it is in the 80's, etc.  What has been explained is the process is as expensive as brick and hence, why not just brick instead of stucco .. if that be the case?

Bottom is Abott Laboratories has a policy with their employees not to buy a home with stucco exterior.  I have had a hard time in the past with relocation clients who liked the layout of the home but becaue of a policy, they didn't buy.  Obviously, they knew something we didn't.

Personally, I like the idea of this type of an inspection.  It scares me to think of what is under vinyl siding where homes don't have the proper overhang, and water runs down underneath the vinyl siding.  You can see bulges here in Chicago ... it is only a matter of time.


Posted by Barb Van Stensel about 8 years ago

Michael - I know that infrared moisture scans have given a lot of people in my area a false sense of security.

Russel - installation details on stucco are critical, you're completely right about that.  As for invasive testing though... I disagree.  I don't know of a single person in my area that relies on that type of testing.  

Loren - I've heard the same thing, stucco seems to perform much better in dry climates.  I suppose most stuff does.

Johnathan - invasive moisture testing wouldn't be considered part of a home inspection.  There are separate companies here that just do moisture testing.

Charles - stucco.  The real stuff.  Synthetic is worse though.

Craig - you nailed it.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

James - what type of moisture meter?  You're right, I didn't mention anything about proper conditions.   I remember meeting an inspector to perform an IR scan on a stucco home about six years ago, and he had arrived at the house before the sun was even up.

Dale - I'm talking about real stucco.  

Barb - I have the feeling that these inspections may start getting more popular on other types of siding.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

The suits are on the "homesafe" home page. As well as the  large number of members of my association that has been sued and lost. Check it out they have a bunch of patents.

Clint McKie

Posted by Clint Mckie, Desert Sun Home, Comm. Inspection 1-575-706-5586 (Desert Sun Home, commercial Inspections) about 8 years ago

Reuben, invasive moisture meter testing of hard coat stucco I would think could be useful---but a concrete scanning type moisture meter would seem invaluable as a starting point prior to drilling holes.  I know that the accepted method of drilling holes in EIFS is to drill two 1/8" holes the width of the probes at an upward angle would be acceptable in hardcoat stucco as well.  There are plenty of quality sealants that can be used to satisfactorilly plug these holes.  I would not even consider this approach all that "invasive"---more damage is done opening attic accesses and electrical panel covers :)

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 8 years ago

@Clint, those patented proceedures appear to be proprietary to Homesafe---why would anyone use them without being licensed to do so?  I cannot imagine anyone being sued for using an IR camera if they were not using their patented proceedures.  Am I missing something?

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 8 years ago

Hi Reuben.  Nice article and glad you included the link to the paper from the City of Woodbury Building Division.   Excellent advice on Required Reading.

Posted by Jim Mushinsky (Centsable Inspection) about 8 years ago

Clint - those Homesafe lawsuits need to go away.  They don't have the market cornered when it comes to using an IR camera for home inspections.

Charles - I don't do invasive testing on stucco, but I've sat through seminars on the subject and spoken with several local experts on the matter, and they all say the same thing; moisture meters are quite useless when it comes to testing for moisture intrusion in stucco.  As for EIFS, they don't even drill pilot holes - they just pop the pins right through the foam.  I'm with you, I don't consider this to be all that invasive... but boy, do some people freak out about this stuff.

Oh, btw, for any ASHI members reading this comment thread, check out this link

Thanks Jim, I've given out that link to the City of Woodbury's position paper many, many times. 


Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

We're supposed to be doing visual inspections. The more gadgets you use the less visual your inspection becomes and the more reliant you become to the correct interpretation of those gadgets. 


Posted by Robert Butler, Montreal Home Inspector | Aspect Inspection (Aspect Inspection) about 8 years ago

Robert - invasive moisture testing and home inspections are two completely separate animals.  

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

I think James nailed it - themal imaging needs the proper conditions to be accurate, and follow up with physcial testing is the way to get teh right answer every time.  I have no problem with the invasive method and have done quite a few with my deep wall probe.  I have had no luck using the Tramex meter Russel uses - it just is too hit or miss for me to rely on compared to themal imaging and the Delhort moisture meter probes.  Good article!

Posted by Joseph Michalski, PA Home Inspector (Precision Home Inspection) about 8 years ago

Thanks Joseph.  As a follow up to this post, I'm writing a post about interior vs exterior testing.  

I spoke with four of the bigger invasive moisture testing companies in my area at length about this issue, and they all said the same thing about IR cameras; they were excited when IR technology became available, they bought cameras, they went through training, and they used the cameras at every house for a while, hoping to start using them exclusively, but they've all completely given up hope of being able to use an IR camera in place of invasive testing.  

None of them are using an IR camera on stucco houses at all any more; it's proven to be a waste of time.  If anyone could reliably use an IR camera to find moisture intrusion in stucco houses, they would make a mint here in Minnesota.   There is certainly a big demand for this kind of service here, as most people detest the idea of drilling holes in walls to check for moisture, but invasive testing has proven to be the only reliable way of checking for moisture in walls.  There are just way too many false positives or missed wet areas for IR scanning to be of any use.

Surface scanners, such as the Tramex meter, are useless when it comes to stucco; they don't scan deep enough from inside the house, and when used from the exterior, they can't scan through the metal lath in stucco.  They're great for EIFS, but we have very little of that in residential construction.  I've seen one house with EIFS, ever.

Until something better comes along, we're stuck drilling holes in walls.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Good post Reuben.  IR is not very effective by itself on stucco, or even EIFS, and only somewhat effective, in my experience, with other tools.  As to Tramex, that is only intended for EIFS and I don't think can work on stucco.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 8 years ago

Thanks Jay.  You're completely right about the Tramex moisture testers; they don't advertise anything about stucco on their web site, and a nice woman answering the phones at Tramex named Penny told me the testers won't work on stucco.  At least not stucco with metal lath... and that's about all we have here in Minnesota.

If the Tramex testers are working for Russell in California, the houses don't have metal lath. 

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago


Funny, I just did a blog on stucco and used the same report (Woodbury) in it. I think the number one issue with this type of cladding is installation.

Posted by Donald Hester, NCW Home Inspections, LLC (NCW Home Inspections, LLC) about 8 years ago

That really is a great report from Woodbury, isn't it?

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) about 8 years ago

Ahhh....a great blog about a very important real estate topic for those seller's and buyer's here in Woodbury, MN. A seller should already have had their stucco tested by a reputable firm prior to putting the home on the market and the inspection should be very current and not several years old or when the seller purchased the home. Any buyer should do due dilligence prior to buying. The cost to replace or repair the stucco can be astronomical.

Posted by John Durham, MS, MS, ASP, ARS (Durham Executive Group - RE/MAX/Results) about 8 years ago