STUCCO: INVASIVE TESTING VS IR 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.

First, 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.  One such company that offers this service is Certified Moisture Testing, who we have recommended many times over the years.

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

Having 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 - Email - Infrared Home Inspections

    

Thermal Imaging and Home Inspections

We’ve been using an infrared camera at random home inspections for the past several months, and we’ve decided that this is by far the coolest home inspection tool in the world.  It’s also pretty useful.  Today I’m going to share some of the problems we’ve been able to identify with this camera that we might not have identified without.

Roof Leaks

With all of the ice dam inspections we’ve done in the last month, we’ve looked at a ton of leaking houses.  For each photo in the series below, I made a duplicate of the original image, then overlaid the thermal image on top of the original.  It’s pretty easy to identify the wet areas in the thermal images, but they’re not apparent in the original photos.

All of the homes shown below had roof leaks from ice dams.

I could share more, but I’m pretty sure I’ve made my point.  Thermal imaging can be used to find roof leaks.  The one caveat to finding roof leaks is that the conditions have to be right; if it’s a hot summer day and there hasn’t been any rain for a week, forget it.

Hot Spots In Attics

Warm attics cause snow to melt, which is what causes ice dams.  I’ve found an infrared camera to be invaluable while troubleshooting the causes of ice dams.

The photo below shows a warm spot in an attic that I never would have identified without an infrared camera.  The culprit was a flush-mounted light fixture with light bulbs that had too high of a wattage.  I don’t make a habit of taking apart light fixtures to check the wattage on light bulbs, but I’ll do it if something tips me off.

Uninsulated ductwork in an attic is also a problem; the heat loss is quite obvious with an infrared camera.  The photo below came from an attic with an insulation value of R-60.  Who would have thought it?

Recessed lights are a huge contributor to warm attics, whether they’re airtight or not.  I’ll be writing a blog about this soon.

Improper Insulation

This is one of the most obvious uses for an infrared camera.   The photo below shows an attic access panel that wasn’t properly insulated.

This next image shows an interior wall that was very cold, because there was a missing section of insulation in the attic behind this wall.

The photo below shows the same section of wall, as seen from inside the attic.

In the photo below, there is an obvious cold spot where the insulation was missed or improperly installed.

Heating Systems

If a radiator doesn’t heat up properly, it will be quite obvious with an infrared camera.  The photo below shows a radiator working properly; while I’m not demonstrating a problem here, I just thought this was a cool image to include 

If there are voids or leaks in heating tubes for in-floor, in-wall, or in-ceiling heat, an infrared camera will probably find them.  The photo below shows an inconsequential gap in the tubing at this heated ceiling.

I’m sure I’ll have plenty more interesting photos to share as the months go on, but these photos should help to answer the question everyone asks: “Why would I want an infrared scan with my home inspection?”

For the record, one thing we don’t offer and never will offer is infrared scans on stucco homes in lieu of invasive testing.  I’ll have more on that topic another day.

Reuben Saltzman, Structure Tech Home Inspections - Email - Maple Grove Home Inspections