The Home Inspector

Reuben Saltzman is a second-generation home inspector with a passion for his work. Naturally, this blog is all about home inspections and home-related topics in the Twin Cities metro area. In addition to working at Structure Tech, he is also a licensed Truth-In-Sale of Housing Evaluator in Minneapolis, Saint Paul and several other cities.

Posts about Real Estate

Photos from New Construction Home Inspections, Part IV

Posted by: Reuben Saltzman Updated: November 18, 2014 - 6:28 AM

It's been a year since my last post on new construction home inspections, so it's time for another.  My message is pretty simple: new homes should be inspected by private home inspectors.  Home inspections aren't just for old houses or used houses.

One of the newest inspectors on our team is Patrick Brennan, who worked as a project manager for Charles Cudd building new homes for many years.  Because of his background in home building, Patrick brings some excellent perspective to the table when it comes to inspecting new construction homes.  For the majority of the new construction inspections that Patrick has done for us, the builders have actually been quite appreciative for the inspections that we provide.  It gives the builders a chance to address defects before they turn into big problems, and there are no occupants that have to be disturbed while corrections are taking place.

Here are some of the most common arguments that we hear against new construction inspections:

  • The house has already been inspected plenty of times by the city.  We're private home inspectors.  We only have one or two inspections to do each day, so we often spend more time during our single inspection than the city inspectors all spent combined at the home.  This isn't a knock against city inspectors; it's simply a fact that private home inspectors have the luxury of more time.
  • The builder already has a one-year warranty, so anything that comes up later will be addressed by the builder.  We do a lot of inspections for clients right before their one-year warranty is up because they've had a lot of problems with the builder, and sometimes can't even get the builder to come out.  Builders also seem to be much more responsive to problems that come up before the closing than after the closing.
  • If you're paying a private home inspector to find problems, they're going to come up with problems.  Most of 'em won't be real.
  • A private home inspection is a waste of money.
  • The builder won't fix anything the home inspector comes up with because the house already meets code.

Instead of arguing the rest of these points individually, I'll let the photos speak for themselves.  These are all issues we've found during new construction inspections over the past year.  Some of these photos are from pre-drywall inspections, and some are from one-year warranty inspections.  The point of sharing these photos isn't to make home builders look bad; the point is that everyone is human, everyone can make mistakes, and the home inspector can help to make sure that many of these mistakes are addressed.  We identify problems with houses long before they become expensive to fix.

Click any of the photos for a larger version.


A large portion of the exterior house wrap was improperly installed at this home.  We identified these defects during a pre-drywall inspection.  These are the types of defects that can lead to major water damage, sometimes after the builders 10-year warranty has expired.  It's not a big deal to fix this stuff today.

Exterior - flashing improper Exterior - house wrap improper close-up

Do you see what went wrong with the installation of the LP Smartside siding shown below?

Exterior - LP Smartside not painted #2

The manufacturer requires a 3/8" gap between the bottom of the siding and the flashing below it, so that the cut edge of the siding can be properly painted.  The diagram below comes right out of their installation manual.

LP Smartside Clearance Above Window

Even when a proper 3/8" gap is left, the siding doesn't always get painted.  The photo below shows a close-up view of a proper gap but no paint at the cut edge of the siding.  If the siding isn't painted at the cut edges, it can experience premature failure.

Exterior - LP Smartside not painted

While we're on the topic of LP Smartside, overdriven nails are another common defect with this siding on new installations.

Exterior - overdriven nails #2

Here's how the manufacturer says to fix this:

LP Smartside Nailing Diagram

Most new-construction homes don't have decks, but when they do, we often find problems with them.  The photo below shows a couple of missing nails at a joist hanger.  Pretty minor stuff.

Exterior - Missing Joist Hanger Nails

This next photo shows a missing metal bracket (joist hanger) at one of the joists.  That's a little bigger.

Exterior - Missing Joist Hanger

And here we have a missing metal hanger at the tripled 2x10s, which was supporting the stairway.  This really needs to be fixed.

Exterior - Missing Hanger

Here's a stairway with improper attachment to the deck.  Each stringer was attached to the header with two 1-1/2" nails going into the corner bracket.  No joke.

Exterior - Bad Stairway Attachment

The J-channel installed on vinyl siding is supposed to be continuous.  This one wasn't.

Exterior - cut in j-channel

On that same window, there was a poorly located seam in the siding, preventing the siding from being attached on this side of the window.

Exterior - Vinyl Siding Defect

The damper for this bathroom exhaust fan didn't open because the plastic grill obstructed it.  The grill obstructed it because the feature board wasn't cut out enough.  This renders the bath fan useless.

Exterior - Obstructed damper terminal


Here's a roofing defect that we were suspicious of before we even went into the attic.  The roofer missed one of the roof vents.  As you can tell from the house wrap, this was a defect we caught during a pre-drywall inspection.

Roof - Missing Vent

Here's what it looked like from inside the attic.  Don't step there.

Roof - Missing Vent (attic view)

Why was the shingle lifted?  Oh, that's why.  Duh.

Roof - lifted shingle

Lifted shingles can lead to shingles catching the wind and blowing off.  That's probably what happened in the photos below.

Roof - Missing Shingles Roof - Missing Shingles #2

Kickout flashings have been required by the Minnesota State Building Code since 2007, so they're nothing new... but we still see 'em bungled.  This first photo shows the kickout bent at a 90 degree angle,  which will create a lot of turbulence and splashing.

Roof - kickout flashing improper

This next photo wasn't from a new construction inspection, but it was a relatively new home, and the installation surely happened at the time the house was built.  Just think about where water is going to go.

not kickout flashing

Here's a home with adhered concrete masonry veneer siding, and missing kickout flashing.  Every little detail on this type of siding is critical, so it really boggles my mind how something like kickout flashing can be omitted.

Roof - kickout flashing missing

Oh, and the stone siding is supposed to be kept at least 2" above the surface of the shingles, not touching them.

ACMV - Required Clearance Above Roof Covering

Here's a peak with two pieces of makeshift flashing that will almost surely leak.

Roof - bad flashing at peak of roof


Even new stuff can leak.  This first photo shows a leaking bath tub overflow drain.

Plumbing - leaking bath tub overflow

Showers can leak too.  We test tiled showers by using a shower dam.  When tiled showers leak, it's a big deal.  This first photo shows our shower dam sitting in the shower.

Plumbing - Leaking Shower

The next photo shows water that leaked through the shower base, down into the garage.

Plumbing - Leaking Shower Evidence

Plumbing vent caps are installed at the roof so the system can be pressure tested to make sure the drains don't leak.  After that, the caps are supposed to be removed.  We find a lot of caps that still haven't been removed. When the caps aren't easily seen from the ground, they're easily forgotten about.  The photo below comes from a new-construction home in Plymouth that I inspected during the winter.  I couldn't safely walk the roof because it was partially frost covered, but it looked like there was a test cap still in place at the plumbing vent.  I put this in my inspection report, the buyer brought it up to the builder, and the builder said it would be taken care of.

Plumbing - test cap in place original

The client was suspicious that it had never been done, so I stopped by the house during the summer when I felt safe to walk on the roof to check it out.  Nope.  Never was done.

Plumbing - test cap still present cropped

Dishwasher drains are supposed to be looped to the underside of the countertop.  This is done wrong on a lot of new homes.  I mentioned this condition during my recent blog post on cross connections, but it's worth bringing up again.

Plumbing - dishwasher drain loop missing High loop at dishwasher drain

This next photo doesn't exactly show a defect, just some scary hot water.  A safe temperature is 120°.  Turn the temperature down at the water heater.

Plumbing - hot water

Frost free faucets are great, but they can still freeze when they're not installed properly.  The faucets need to be pitched slightly down, so water can drain out of the stem when the faucet is shut off.  The faucet below was pitched up instead.  I've seen this same defect a few times this year on new construction homes.

Plumbing - backpitched frost-free faucet

Here's another comically small access hole for the bath tub drain.

Plumbing - comically small access hole

Unless one is proficient at building ships inside of bottles, that hole is pretty useless.


Most circuit breakers are only designed for one wire to be connected to the breaker, including the breakers shown below.  One of these breakers had two wires connected.  This is an unusual defect for new construction, but hey, that's why we open panels.  For more info on this topic, click here: Double Tapped Circuit Breakers.

Electrical - Double Tapped Circuit Breaker

All unused openings in electric panels are supposed to be covered up to help contain any fires, and to prevent pests from getting into the panel.  This doesn't always happen.

Electrical - Missing knockout in bottom of panelboard Electrical - Missing knockout plug at back of panelboard

That ground clamp needs to be slid up about an inch so it makes full contact with the copper water supply tubing.

Electrical - ground clamp not making contact

This weatherproof cover won't keep water out when it's installed upside down.

Electrical - Upside Down Weatherproof Cover

We had to check this one a couple of times to make sure we weren't losing our minds.  It was an outlet with reversed polarity.  This is a very unusual defect for a new house, but again, that's why we test the outlets.

Electrical - Reversed Polarity

Here's an especially nasty defect; this outlet was located behind the kitchen drawers under a range top in the kitchen.  The outlet is missing a cover plate, the outlet isn't attached to the box, and the box isn't flush with the surface of the cabinet like it should be.

Electrical - hanging outlet

Here's a missing cover plate at a junction box in an attic.

Electrical - missing cover plate at junction box

Check out the location of this outlet.  It's over ten feet away from the radon vent.  The outlet is there so a fan can be installed if radon levels are high... but what good does it do if it's ten feet away?

Electrical - Radon Outlet

While we're on the topic of radon fans, here's a home where the builder agreed to install a radon fan, but installed the fan on its side.  Radon fans should be installed vertically to help prevent water from accumulating, which can cause the motor to burn out prematurely.

Radon - Fan on side

Here's a GFCI outlet in the attic.  GFCI outlets are supposed to be tested every month... not that anyone really does this, but just for the sake of argument, let's say someone wanted to.  Are they really supposed to go into their attic to do this?

Electrical - GFCI Outlet in Attic

By the way, it's very important for attics to be inspected.  Even on new construction homes.


Same old, same old.  We find a ton of new construction homes with way less insulation than they're supposed to have.

Attic - Insufficient Insulation

How does this happen?  There is no such thing as an "attic insulation inspection" for new construction homes.  No joke.  See my blog post dedicated to attic inspections on new construction houses: Who Inspected Your Attic?

When we perform pre-drywall inspections, we frequently find gaps in the attic "lid" that will be attic air leaks once everything is finished.  The gap between the two top plates (2x4s) shown below shows an example of a future attic air leak.  It's still very easy to fix these air leaks today, but it'll be a P.I.T.A. to find them once there's 14-3/4 inches  8+ inches of insulation throughout the attic.

Attic - Air Leak

Here's an infrared image of a disconnected bath fan duct below the insulation in an attic on a cool day.  There were no visible signs of this defect, but a quick scan with an infrared camera made it quite obvious.  The infrared camera also helped us to know exactly where to dig through the insulation to get a photo documenting the condition.

HVAC - Disconnected Duct in Attic


Lots of air leaks in ductwork.

HVAC - air leaks HVAC - air leak #1

When HRVs aren't balanced, they may either put the house under negative or positive pressure, neither of which is usually good.  Check out my recent blog post about siding stains; putting a house under positive pressure would contribute to stains like that.  If the balancing damper (circled below) isn't screwed into place on the HRV, it hasn't been balanced.

HVAC - HRV not balanced

Someone installed a damper on this HRV intake, which prevents the HRV from pulling any fresh air into the home.  Easy fix, bad mistake.

HVAC - Damper on HRV Intake

Here's a furnace intake and exhaust flipped around.  This will cause the corrosive exhaust gases from the furnace to get sucked back into the furnace.  Again, easy fix, bad mistake.

HVAC - Furnace Intake and Exhaust Backwards

Would you accept this crooked hood fan installation?  This is purely cosmetic, but still...

HVAC - crooked hood

Toekick heat registers in kitchens and bathrooms are almost always done poorly in new construction homes.  So poorly, in fact, that I put together a countdown of the top five worst toekick registers I've seen at new construction houses this year.


HVAC - Toekick 5


HVAC - Toekick 4


HVAC - Toekick 3

#2 - look carefully.  I drew a thin black rectangle on this image to highlight the effective opening.

HVAC - Toekick 2


HVAC - Toekick 1

It's called a "toekick", not a "footstomp".

Interior Stuff

Spray foam insulation is great stuff and I'm a big fan of it, but it won't work right if it's not installed right.  Check out this article on Spray Foam Insulation Problems at the Journal of Light Construction web site.  I'm not exactly sure what went wrong with the installation of the spray foam at these rim spaces shown below, but I know wrong when I see it.  There were obvious voids in the insulation at these houses that need to be addressed.

Interior - spray foam insulation problems Interior - spray foam problem

What happens during the summer when you build a home with an exhaust-only ventilation system and the poly on the wood framed portion of the basement wall isn't perfectly sealed?  Humid outdoor air will leak into the basement wall cavity and then condense on the relatively cold poly.   There was so much condensation on the poly at this home that water was pooling at the base of the wall.  The builder had already attempted to fix a supposed leak at the window twice, but this was simply condensation.

Interior - incomplete vapor barrier Interior - incomplete vapor barrier #2

Side note: This is the opposite of what I blogged about last week.  Siding stains show up during cold weather at the upper levels of the home, and 'supply-only' ventilation will exacerbate this condition.  Good stuff, huh?

The fix is to make the poly 100% airtight, or to insulate the wood-framed portion of the wall with closed-cell spray foam insulation.  For the record, I'm no hypocrite; I had that done at my own house three years ago: Spray foam insulation at Reuben's house. Here's a joist cut all the way through.

Interior - cut joist

That's obviously the wrong joist hanger.

Interior - wrong joist hanger

These metal brackets aren't right either.

Interior - wrong hangers

Here's a wall that completely missed the anchor bolts, or more likely, the anchor bolts weren't properly located.

Interior - Missed Anchor Bolts

Here's a sump basket cover that isn't sealed.  An unsealed lid will allow humid air into the basement, as well as radon gases.

Interior - sump cover not airtight

Not only was this sump lid not sealed, but someone used that hole in the sump basket to dispose of their coffee cup.  That coffee cup could float into the wrong spot and prevent the float from operating the sump pump... which could lead to a flooded basement.  Get the trash out.

Interior - Sump Basket with Coffee Cup

Whew.  That's enough for this year.  These blog posts on new construction inspections keep getting longer and longer.  Again, this isn't a knock against builders.  The point here is that a new house doesn't mean a perfect house.  Even new houses should be inspected by private home inspectors.  If you already own a new home and never had it inspected, consider having your home inspected before your one-year warranty is up.  We do a lot of those inspections.

Related Posts:

Author: Reuben SaltzmanStructure Tech Home Inspections


Moisture Testing Homes with Vinyl Siding

Posted by: Reuben Saltzman Updated: November 4, 2014 - 6:31 AM

While the majority of our moisture testing is done on stucco homes, moisture testing isn't just for homes with stucco siding.  Moisture intrusion can happen with any type of siding, and it's always an expensive repair when left unchecked.  Just recently, some friends of mine expressed concern about some dirt that started showing up below the corner of their living room window, so they asked me to take a look.  The photo below shows the "dirt" they were talking about; click on the image to see a larger version.

Dirt below window

Can you guess what caused it?

The title of this blog post probably gives it away, but before I show photos of the rotted wall, let me first explain all of the stuff that went wrong.  To start, here's a photo of the front of the house.  It's a little tough to see through the tree, but there are no gutters at the upper section of the roof, and the valley at the upper roof dumps water onto the lower roof.  From there, the lower roof is supposed to direct water into the gutter.

Front of house original

If there had been gutters installed at the upper portion of the roof, all of that water would have been dealt with, but instead the lower roof gets pounded.

Kickout FlashingAt the lower portion of the roof, there should have been a piece of kick-out flashing installed where the roof ends above the window, but there was none present.  This allowed water that ran down the roof/wall intersection to leak in behind the vinyl siding.

Finally, there was no water-resistive barrier installed behind the vinyl siding.  As I mentioned in my blog post about how to inspect your own siding, vinyl siding isn't designed to be watertight.  It's only supposed to keep most of the water out.  It works because there is supposed to be a weather-resistive barrier installed behind the siding, such as Tyvek®, which is a brand name that is somewhat synonymous with house wrap.  Unfortunately, water-resistive barriers weren't specifically required by the MN State Building Code until 2003, so it was pretty much hit and miss up until then.  In this particular case, it was "miss".  Without a water-resistive barrier, all of that water that leaked in behind the siding ended up saturating the wall sheathing and leaking into the wall cavity, where it caused major damage.

I did some moisture testing around the window to confirm my suspicions, then we took the siding off to get a good look at the damage.

Water damage behind vinyl siding2 Water damage behind vinyl siding3 Water damage behind vinyl siding4 Water damage behind vinyl siding5

Nasty, huh?  Thankfully it was just vinyl siding, which does a pretty good job of allowing the wall to dry out. If this had been stucco siding, the damage likely would have been much more extensive and the repairs much more expensive.

Remember, the only visible evidence of this water damage was the little black flecks that had made their way through the window and landed on the carpet.  I suspect those were little pieces of rotted wall sheathing blowing into the home during periods of heavy wind, but I'm not 100% sure.

This is the type of damage that home buyers try to avoid when buying any home, and this is why some home buyers choose to have moisture testing performed on homes with vinyl siding.  Vinyl does a great job of hiding this kind of damage.  While moisture testing on stucco homes is considered an invasive inspection and requires special permission from the homeowner, moisture testing of vinyl sided homes is done by using a non-invasive surface scanner to quickly scan large areas of the siding for moisture intrusion, and then followed up with pin-probe testing behind the siding to verify the results of the surface scanner.  The siding is then popped back into place, leaving the siding in it's original condition.  This is a non-invasive inspection that requires no special permission from the homeowner.

Included below is a short video clip showing Antonio and I performing moisture testing on a 2007 built townhome that had moisture intrusion below the deck. 

If you're buying a home with vinyl siding or you already own a home with vinyl siding and there is concern about water intrusion, have moisture testing performed.  Vinyl sided homes with no moisture barrier should always raise concerns, but as seen in the video clip above, moisture intrusion can still occur when a moisture barrier is present.  For information about how moisture testing is done on other types of siding, click here:

Author: Reuben SaltzmanStructure Tech Home Inspections


Why Home Inspectors Should Know Building Codes

Posted by: Reuben Saltzman Updated: September 22, 2014 - 5:18 AM

In last week's blog post, which I did not post here on the Star Tribune, I mentioned that there is an upcoming seminar for Minnesota home inspectors, being taught by building code guru Douglas Hansen of Code Check.  Minnesota currently uses the 2006 International Building Code (IRC), but we'll soon be adopting the 2012 IRC, and with that will come a lot of changes.  The upcoming seminar will cover the most important parts of these changes.

Side note: Why are we flying in a national code guru from California to teach this 8-hour seminar when the class has already been put together and is being taught by some extremely knowledgeable and capable building officials right here in Minnesota?
@#$!%* beaurocracy, plain and simple.  The folks that I've reached out to at the Minnesota Department of Labor and Industry have told me they're not allowed to do any teaching outside of the state curriculum because there's a conflict of interest.  I have no idea what the conflict could possibly be, and I'm not at all satisfied with that answer, but in the interest of getting this class put together and notifications sent out to MN home inspectors in a timely manner, I didn't fight the issue.  I'm not done with it though.

I sent out an email notification to all of the Minnesota ASHI members letting them know about this seminar, and I've been making phone calls as well to make sure that everyone got the word.

I had one conversation with another Minnesota home inspector, who I'll call Inspector X, that prompted me to write this post.  When I told Inspector X about the upcoming seminar that would be covering the code changes to the IRC, I said I considered this  seminar to be 'must-have' training for any home inspector in Minnesota.

Inspector X said he disagreed that this is must-have training, because he doesn't conduct code enforcement inspections in any capacity.  I didn't have time to engage at the moment, so I just told him he was right, home inspections are not the same as code enforcement inspections, but it's still important for us to be familiar with current building codes.  I couldn't get him to agree with that either, so I basically just wished him well... but if I had had the time, I would have explained it this way:

ASHI Home Inspection Standards of Practice require home inspectors to provide clients with a written report that states those systems and components inspected that, in the professional judgement of the inspector, are not functioning properly, significantly deficient, unsafe, or are near the end of their service lives.

Unsafe is defined as "A condition in a readily accessible, installed system or component that is judged by the inspector to be a significant risk of serious bodily injury during normal, day-to-day use; the risk may be due to damage, deterioration, improper installation, or a change in accepted residential construction practices."

Current building codes are what define accepted residential building practicesIf a home inspector is not familiar with current building codes, they're not familiar with accepted residential building practices.

Code Knowledge vs. Code Inspection

Even though home inspectors should be familiar with current building codes, this doesn't mean that home inspectors should report code violations.  Our standards of practice clearly state that home inspectors are NOT required to determine "compliance of systems and components with past and present requirements and guidelines (codes, regulations, laws, ordinances, specifications, installation and maintenance instructions, use and care guides, etc.).

If you want to know the difference between a code compliance inspection and a home inspection, look at the reasoning behind the recommendations for change / repair.  ASHI Standards of Practice require home inspectors to report the reasoning or explanation as to the nature of deficiencies reported that are not self-evident.  If the home inspector bases their reasoning on code, they're heading into 'code compliance inspection' territory.

As an example, take a look at the sump basket cover at this new-construction home; the cover isn't airtight, which will allow for moist air to enter the home.  This air may also bring radon gas into the home.

unsealed sump basket cover

Here's a bad way for a home inspector to report on this: "The sump basket cover was not airtight, which is required by Minnesota Administrative Rule 1322.2103, Section AF103.4.4.  Have this corrected."

The problem with this type of reporting is that it tells the client that this is a problem because the installation does not meet code... and that's about all.  It doesn't give the reasoning or explanation as to the nature of this deficiency.

The proper way for a home inspector to report this type of defect would be "The sump basket cover was not airtight, which will allow for air to leak into the building.  This air will have relatively high levels of moisture, and will contribute to radon gases coming into the home.  Have the sump basket cover made airtight."

See the difference?

If the home buyer addresses this issue with the builder and asks them to correct this, the builder might say it already passed inspection and meets code.  At that point, a home inspector who is familiar with building codes would be happy to give their client the above code reference, backing up their recommendation.  That's a good thing, and it doesn't mean the home inspector is doing a code compliance inspection.

Author: Reuben SaltzmanStructure Tech Home Inspections


Radon Testing: Should Home Buyers Rely on the Seller's Test?

Posted by: Reuben Saltzman Updated: September 8, 2014 - 10:00 AM

We routinely get requests from past home inspection clients of ours asking us to re-send the radon gas test results from testing that we conducted many years ago. We get these requests because our past clients are now selling their home, and they’re performing their due diligence attempting to gather whatever information they can about their home to give to potential home buyers. In most cases, we still have the results and are happy to send them out. We recently received an email asking about this:

"Two months ago the seller had another buyer inspect the home.  The radon test came back at 1.8.  Does this need to be done again? Thanks!"

That's a great question.  Here's my generic advice on relying on the seller's test results.

Over Two Years Old? Forget it.

How much value is there in old radon test results? If the test results are more than two years old, the EPA recommends conducting a new test. If the test results are less than two years old, there might be some value in those results.

Who Conducted the Previous Radon Test?

If the test results are less than two years old, find out who conducted the radon test before relying on the results. For obvious reasons, I don’t recommend relying on any type of DIY radon tests unless you Did It Yourself. If the radon test was professionally conducted, make sure the person / company conducting the test was qualified to do so. You’d hope that any home inspector charging money to conduct a radon test would be qualified to perform the test and would do it properly, but I’ve personally seen enough egregious testing errors to know that there are plenty of unqualified folks conducting radon tests in Minnesota. While there are no licensing requirements for radon testing companies in Minnesota, there are two large certifying bodies for radon measurement providers: the National Radon Proficiency Program (NRPP) and the National Radon Safety Board (NRSB). I’d feel fairly confident in relying on the radon gas test results from an NRPP or NRSB certified company. That’s not to say that you shouldn't rely on the results from someone who isn't certified, but you’d be right to at least ask a few questions about the qualifications and experience of the person / company doing the testing.

Has Anything Changed?

If there have been any major structural changes, HVAC changes, or there have been any significant projects that involved air sealing, which is most commonly done in the attic, don’t go with the old test results. Too much has changed that may have affected the radon levels. Have your own test conducted.

Where Was The Test Placed?

When a homeowner conducts a radon test on their own home, they’re supposed to test the lowest level of the home that is regularly used. If the home has an unfinished basement and nobody spends any time down there, the test should be placed on the first floor. When a radon test is conducted as part of a real estate transaction, the radon test should be placed in the lowest livable part of the home, whether it’s finished or not.  If a home buyer is going to rely on the seller’s radon test results, they should make sure the test was placed in the lowest livable area, not the lowest level that is regularly used.

In Conclusion

If a home buyer is going to rely on someone else's radon test results instead of hiring their own company to conduct a radon test, they should make sure that the previous test was done within the last two years, the testing was done by a qualified person / company, no major changes happened at the home that could affect radon levels, and that the radon test was placed in the proper location.

Author: Reuben SaltzmanStructure Tech Home Inspections


How Accurate is Exterior Moisture Testing?

Posted by: Reuben Saltzman Updated: June 5, 2014 - 6:08 AM

This is a guest blog post by Barry Eliason, of Structure Tech Home Inspections and Private Eye Moisture Testing. 

I received a call a few weeks ago that was typical of calls I get several times a year. It was the real estate agent for a client of mine that had recently hired me to do a moisture test on a stucco home they were buying. The moisture testing had found several areas of high moisture and even some soft or missing sheathing, indicating some structural damage. The sellers of the home questioned the accuracy of my report and hired another company to re-test the house. This other company did their testing from the interior rather than from the exterior as I had done. Their report to the home owners? “Every place we tested was dry”.

The agent on the phone was politely asking me if I thought I had gotten it wrong. First I summed up the situation. “Well, you now have two different opinions and we need to know which one of them is correct.” He agreed and wondered how to resolve the situation. My answer was to do what I had recommended in my initial report: remove some small pieces of stucco in the areas that tested high and see what's going on.

How do we test for moisture?

Moisture MeterThe pin probe testing that we do involves drilling two small holes, using a 3/16” drill bit,  about one inch apart through the stucco at each test site. We then insert the probes of a moisture meter into these holes and pound them into the sheathing material that is just behind the stucco. The sides of these probes are insulated to protect them from contacting the stucco or the metal lath  fastened to the exterior of the sheathing. The moisture meter passes a small electrical charge between the probes and calculates the percentage of moisture, by weight, of the material being tested based on the level of conductivity. If a material is wet,  it's a better conductor and results in a higher reading.

What do the readings mean?

Any reading of 15% or less is considered normal in an exterior wall. A reading of 20% or more indicates excessive moisture and the possibility of structural damage; if not now, certainly over time. A reading of 15-20% is higher than normal and indicates some amount of leakage. Wood materials won’t start to rot until their moisture level reaches about 28%, but the decay process will continue until the material dries back down to 20% or less. If it never goes above 28% there may never be any damage. Wood and wood materials are considered to be saturated at about 40%.

Sometimes, as the drill bit passes through the back side of the stucco and encounters the wall sheathing there is little or no resistance and the drill bit pops right into the wall cavity or wooden framing member. This indicates structural damage- usually caused by a moisture problem.  This is indicated in the report as "Soft" or "No sheathing detected".  In some cases, when the sheathing is completely rotted away, there is nothing left to hold moisture anymore.  In that situation it is possible that the moisture meter will not detect any high readings, but the lack of any sheathing indicates a problem and possible structural damage.

How accurate are the results?

I’ll be the first to admit that this testing method is not perfect and there is always the possibility that in spite of my best efforts the probe touches something unexpected that produces a false high reading. Usually these “false positives” are isolated high readings surrounded by one or more normal readings. Two or more high readings in an area reinforce their accuracy. I always try to take multiple readings when I encounter areas of high moisture. Contractors that have removed stucco for repairs based on my testing tell me that I usually “nail” it. Most reliable contractors insist that a comprehensive moisture test be done before they start ripping stucco off of the house. When the stucco is finally removed the extent of the damage is often much more than the home owner ever imagined.

What should be done if the report says "wet"?

Exploratory Hole in StuccoBecause there are seldom any visual clues as to the extent of the damage, or what is causing it, I recommend that a small area of stucco be removed - about a 6" x 6” area - to verify the accuracy of the test. If this small square is done at the bottom corner of a window it can also give us a clue as to what is causing the failure and what it will require to correct it. Once the stucco is removed (we call this a stucco cut) the sheathing can be re-tested with a moisture meter to verify the accuracy of the original reading. Remember, if the sheathing has never gone over 28% it will not appear to be damaged. In fact, it may appear to be just fine, but the sheathing is in a part of the assembly that by design should always be dry. Even after a driving rain, or during days of high humidity, this part of the wall should be dry. If it is above 20% there is uncontrolled moisture entering the system. This is a problem and steps need to be taken to stop it.

Do we ever get it wrong?

It's extremely rare to have a stucco cut reveal that our initial probe test got it wrong. This is usually the result of the probes touching something like a metal flashing, aluminum tape, a cluster of staples or the wire stucco lath. This is what is referred to as a “false reading”. Yet, this is what those with a vested interest in the testing being wrong hang their hat on. Our testing has about a 95% accuracy rate but the party that stands to lose big bucks if we're right will sometimes try to get the entire test thrown out based on a small percentage of false positives. This can be real estate agents, home builders and their insurance companies, and sometimes homeowners. Everyone is entitled to their opinion as the the accuracy of a moisture test, but they are not entitled to their own facts.  The results of a probe test are a fact. The accuracy of that test is an opinion. The only way to prove or disprove the accuracy is to start peeling back the layers and see what is going on with our own eyes.

Getting back to the story...

The real estate agent took my advice and had a stucco contractor come out to make some exploratory holes in the stucco to get a look at the sheathing.  Can you guess what was found?

The sheathing was wet and damaged enough so that the exterior surface could be scraped off with your fingers! It’s entirely possible that the interior side tested by the other company was still dry and undamaged; for now. This house was a ticking time bomb and was going to cost somebody a lot of money to fix. By spending under $500 for a moisture test, my client saved themselves tens of thousands of dollars and a lot of heartache.

The sellers, on the other hand, wasted whatever they paid for the second test rather than go straight to the stucco cut. Once again, the exterior probe testing method proved to be the most accurate,  minimally invasive and low in cost. After doing thousands of exterior probe moisture tests I am convinced that it is the only way to go.


Author: Barry EliasonPrivate Eye Moisture Testing

Barry has been a home inspector for nearly the past 30 years, and has been the "go-to" guy for moisture testing inspections in the Twin Cities since 1998.


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