Invasive moisture testing stucco homes

Your home inspection is non-invasive

I don’t think a lot of sellers would be happy if a prospective home buyer (or his/her home inspector), cut holes in the walls or broke up concrete in the basement to see if there were any problems. The home inspection is considered “non-invasive”, or visual only”.

Having said that, there is a place for invasive testing, and that’s where there might be moisture behind the siding that can’t get out, such as faux stone veneer, new stucco and EIFS (Exterior Insulated Finishing System, pronounced “eeffs”)

The city of Woodbury did a White paper, In it, a city official estimated that at least one half of the stucco homes studied would fail within 10 years of construction. And high levels of moisture has been blames for a bevy of health issues, from asthma

The home inspection looks for possible problems, such as penetrations around windows, doors and decks. Because most moisture problems are not visible, invasive moisture testing is recommended.

Invasive moisture testing involves drilling very small (1/4″) holes in the siding and sticking in two thin probes to test for moisture and check for soft wood. When the testing is done, the repairs are nearly impossible to see. If moisture is found, invasive repairs are recommended. Caught early, repairs may be minor.

Otherwise, the costs may be very high. The folks at Building Spec in Virginia recommend regular testing as long as you own the home. You can learn more by clicking: Invasive Testing.,

So, what does a home inspector look for? Lots of things. Missing or improperly installed kickout flashing is high on the list, because water rushing off the roof and hitting a wall (or worse, a window), actually drives the water behind the siding, where it may not escape before saturating the wood or insulation, leading to mold and decay.

Penetrations in the siding should always be properly caulked. Caulk doesn’t last forever. It should be checked for weathering at least yearly, and replaced as needed.

Are there storm windows? Check to make sure the little “weep” holes on the bottom aren’t caulked shut of full of dirt; give any accumulated water a way to get out.

So, if your house was build anytime in the 80’s or after, invasive moisture testing might be a good idea. There are a lot of companies that can do the job. I’ve heard good things about Certified moisture testing.

I’ve also heard good things about current building methods, where allowances are made for the water that does enter the cavity. Here’s a link to that: Proper stucco installation.