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.
The 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.
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.
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.
Because 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.
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.
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.
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.
If you're buying an old house, beware of old water pipes; specifically, galvanized steel. These pipes build up with sediment on the inside, making the inside diameter of the pipe smaller and smaller over time, eventually to the point where water flow is unusable. These pipes also corrode at the joints, which can lead to leaks.
The mere presence of galvanized pipes doesn't constitute an immediate action item, but it does mean that the water distribution pipes in the house should be looked at and tested more thoroughly during the home inspection, especially if there is any evidence of past leaks.
The water supply piping is what brings water from the street to the house. To identify the type of material, take a look at the water piping where it comes into the basement before the first shutoff valve, which should be located right before the water meter. If this water piping has a threaded fitting, it's probably a galvanized supply pipe. This is always bad news. The other types of water supply pipes are copper, plastic, and lead. Copper and plastic are good news, lead is not.
If you see a thicker pipe coming up out of the basement floor with threads on the end, it's probably a galvanized supply pipe. Galvanized or lead water pipes were installed in Minneapolis homes exclusively up until 1928, and in Saint Paul homes up until 1925. Minneapolis' transition to copper water supply pipes was complete by 1932, and Saint Paul's transition was complete by 1926.
Most Minnesota homes with galvanized supply pipes have such poor water flow that doing laundry and taking a shower at the same time is not possible. If the home is in Minneapolis, take a look at item #19 on the Truth-In-Sale of Housing evaluation report; this item asks if the water supply piping is copper. If the piping is copper, this item should be marked as "M". If the piping is something else, such as galvanized steel, lead, or plastic, this item should be rated "C" for comment, and there should be a comment stating the water supply piping was not copper.
A better description for item #19 would probably be "Copper or Plastic Water Line Visible on the Street Side of Water Meter", but these reports have a lot of old language in them that takes a lot of effort to change.
If the water piping coming into the home can't be found, access is blocked, or the main valve is located too close to the floor to determine the type of water supply piping, one option is to call the municipal water works department to find out what type of water supply piping the house has. This is easy to do in Minneapolis, as they keep detailed records of exactly what type of water supply pipe was installed, and when it was installed. The two photos below show a home with a galvanized water supply; all that can be seen is copper, but the piping below the earth is actually galvanized.
I've had a couple of inspections in Minneapolis where the water flow throughout the house was quite minimal, yet all of the water piping looked great, and there was a copper water supply entering the house. In those cases, my curiosity got the best of me and I called the water works department to get the history on the water supply. Apparently, the water supply piping didn't always get replaced entirely. In some cases, there would only be a partial replacement out to the street. The fix is to have the yard / street dug up again and have the rest of the water supply replaced.
An easy way to determine a problem with the water supply pipe is to quickly turn on an exterior faucet. If water comes out with a burst but the flow drops noticeably after a fraction of a second, it's almost certainly a problem with the water supply for the house. In most cases, this indicates an old galvanized supply pipe, but could also indicate a problem with an old lead supply pipe. The video clip below shows an example of this, but it's not very easy to see. There is only a slight change in flow, but it was enough for me to know there was a problem.
For a more obvious example, check out the clip below. When the water is turned on at the garden hose it bursts out, then the flow drops down dramatically. This is because there is plenty of pressure, but insufficient flow. A common concern that home buyers express is for the home inspector to make sure the home has "good water pressure", but what they really mean is "good water flow."
The clip shown above was also the first clip in a compilation of 47 home inspection video clips in under 3 minutes that I put together, which I have featured at the top of our home page. I've received a number of requests to explain some of the problems in that video, and I'll be attempting to do that through blog posts over the next year or two.
If the water supply pipe to a house needs replacement, plan to spend several thousand dollars. The yard will need to be dug up and the water supply pipe replaced out to the street. The homeowner pays for this. If the city water line is on the opposite side of the street, it's more expensive. To determine which side of the street the water supply is on, look for fire hydrants.
If the home has a lead supply pipe, water flow may be restricted because of a damaged pipe, but I've inspected plenty of homes with lead water supply pipes that still had acceptable water flow. The other obvious concern with a lead water supply is with lead leaching into the drinking water for the home. In these cases, the water can be tested for lead. Visit the EPA for more info on lead in water.
Galvanized steel water distribution pipes were used almost exclusively in Minnesota homes up until about 1950, when copper tubing began to replace galvanized pipes. Copper gradually replaced galvanized piping during the 1950's, and was about the only thing used for water pipes in homes by 1960. CPVC and PB tubing gained some popularity during the 90's and early 2000's, but today PEX is pretty much the only thing used for water distribution piping in new Minnesota homes.
To identify the presence of galvanized pipes, start by looking in the basement. As soon as the water supply pipe enters the house, there will be a shutoff valve, a water meter, then another valve. After that, the water distribution pipes will branch off to the rest of the house. If the home has been re-piped or partially re-piped, it will probably have been done with copper or PEX tubing. It's easy to tell the difference between copper tubing and galvanized pipes because galvanized pipes have threaded fittings, while copper tubing has soldered joints.
If the home has been partially re-piped, there will typically be newer copper tubing in the basement, and the water lines will transition to galvanized piping at the basement ceiling just before disappearing into the walls. The photo below shows an example of a partial replacement by some complete hack.
Sometimes, houses can have galvanized pipes that are still in acceptable condition, and water flow is still acceptable. To help determine if water flow is acceptable, try this test that I've adopted from the Minneapolis Truth-In-Sale of Housing Evaluator Guidelines. Start by running hot and cold water at the laundry sink faucet, then run upstairs to the highest plumbing fixture, preferably a shower, and verify there's still water flow. If there is no water flow or insufficient flow to take a shower, it's a major concern.
In most cases, no flow at the upper fixtures under these conditions indicates a problem with the water supply pipe, or old galvanized water distribution pipes in need of replacement. A couple of other possibilities would be a main shutoff valve that's partially closed, or a problem with a water softener that restricts water flow throughout the house.
There are too many variables for me to cover every possible scenario, but hopefully these tips give enough info to conduct a basic test for water flow on old houses.
Author: Reuben Saltzman, Structure Tech Home Inspections
This blog post is a compilation of three blog posts written by Reuben, which originally appeared at the moisture testing web site www.PrivateEyeMN.com.
Moisture testing on relatively newer stucco houses (mid 1980s - late 2000s) has become standard practice when buying a home in Minnesota, and a lot of those tests reveal problems with moisture intrusion. Water intrusion is never good news, but there are several options to consider when exploring a repair strategy for a home with water damage.
Remediation protocols range from retrofit, which consists of partial repair and maintenance, to full tear off and replacement, which consists of removing all of the stucco and replacing with an alternate cladding material, such as James Hardie HardiePlank® or LP Smartside®.
Today we'll be taking a closer look at all three repair strategies, all of which were performed by Sunset Construction Group (SunsetCG), a Minnesota company that specializes in repairing stucco houses with moisture intrusion problems.
When SunsetCG is contacted to perform stucco repairs on an existing home, there are four basic steps that take place; a review of the moisture testing report, removal of the stucco at the affected areas, repair of the affected areas, and maintenance on the rest of the stucco.
The first thing SunsetCG wants to see is the moisture testing report, which is what we provide. This report will contain photos of the home along with moisture readings, which helps to determine the scope of the work and offers professional guidance to the buyer and sellers of a property. From there, a bid is put together on stucco repairs and various repair strategies are explored.
Reviewing this retrofit-level case study, we first performed moisture testing at this home in 2006, and found several areas with high moisture levels, but no repairs were conducted at that time. We performed moisture testing again in 2013, and many of those same areas showed high levels of moisture, so SunsetCG was contacted to perform repairs.
Here's an excerpt from our moisture testing report, showing exactly which areas of the wall sheathing had elevated moisture levels; our results from 2006 and 2013 are documented right next to each other on the report for comparison.
To keep this short, I'm only focusing on a small portion of the house.
As you can see from the moisture testing report above, the big area of concern was directly below the first floor window. The next step was to have a minimal amount of stucco removed around the window, to expose and give access to the water damaged areas. Click the photo for a larger version.
After the stucco was removed, the source and severity of the moisture intrusion were confirmed. The sheathing, framing, and insulation of the impacted areas were repaired or replaced as needed. The impacted areas were then redesigned using improved materials and installation methods, to highly reduce the potential for future moisture problems.
Examples of new materials and methods would be new head flashing above the window and new pan flashing below the window.
The stucco color and texture were then patched and matched as closed as possible, and then the front of the house was painted with a high quality, breathable stucco paint to give the front of the house a uniform look.
While existing stucco homes may not have been constructed with the same details that a new stucco house would be built with today, the areas that have proven to perform over the years are maintained in their current condition with a quality caulk/seal effort. Some areas of particular attention will be the window miters, mullions and perimeter of windows, and vertical transitions between stucco and other surfaces, such as windows and doors.
The theory/risk proposition with a retrofit repair is that the areas that have performed over the past ten to fifteen years will probably continue to perform, even though it may not be an ideal installation. The main benefit with this type of repair is cost; these types of repairs will typically cost 30% - 40% of what a full tear off and redo would be.
When a retrofit repair is performed, a follow-up moisture testing inspection should take place three to five years after the repairs have taken place.
Along with the lower cost of repairs comes a limited warranty on the work. A ten year warranty (per MN State Statute) is not likely to apply under most (if not all) retrofit repair strategies, as the contractor is only touching part of a wall. If a ten year warranty is a must, the next two repair strategies would be good options.
The photos below show a house that had missing kickout flashing at a roof end, which led to extensive moisture damage at the front wall, including sheathing and minor framing repair.
After the stucco was removed and the damaged sheathing replaced, new plywood sheathing was installed, the window was properly flashed, and the first of two layers of building paper were applied to the exterior wall.
Proper kickout flashing gets installed at the roof end, and a quality drainage plane was installed to create an air gap.
The repaired areas are covered by a 10-year warranty, and the cost of the job was approximately $20k. Follow-up moisture testing can be conducted between three and five years after the repair work as a health check-up, as well as to provide documentation to any future home buyers that the repairs are performing as they should.
As is standard practice when buying a newer stucco home in Minnesota, the folks buying a stucco-clad home in Plymouth had invasive moisture testing performed as part of their purchase agreement. Despite the fact that there was no visible evidence of moisture damage inside or outside the home, the moisture testing report showed high levels of moisture in many locations throughout the home.
The home seller contacted SunsetCG to verify the results of the moisture testing, and the results were confirmed by cutting exploratory holes into the stucco; this helped to confirm the problem and determine the extent of the water damage.
Side note: If you ever happen to see a stucco home with caulked squares of stucco, you're probably looking at a home that has had exploratory holes cut. The photo below shows what these exploratory holes look like after they're patched.
After the home sellers were shown the extent of the moisture damage inside the walls, they decided to have the stucco completely torn off and the home resided with a different product. They decided to go with James Hardie® fiber cement siding, which has become a very popular product on new homes throughout Minnesota.
The photos below show the home before the stucco was torn off, while it was being repaired, as well as the finished product.
While a full tear-off and redo is the most expensive option when it comes to stucco repairs, there are plenty of benefits to this method. Instead of having only the areas with damage / water intrusion repaired, everything is opened up and redone. For example, pan flashing gets installed at all of the windows, proper kickout flashing gets installed at all of the roof ends, and the deck is completely re-flashed at the ledgerboard. At-grade or low wall plate lines that are too close to grade can be exposed and re-designed at the same time. All of the siding is now covered under a full 10-year warranty per MN Statute 327A, which can be a very attractive feature for potential home buyers. Finally, the stigma associated with newer stucco homes is removed.
For a full stucco tear-off and re-do, the cost can go into the six-figure realm, but of course this price involves all of the stuff that happens under the siding; it's not just about replacing existing siding. It's also about figuring out and repairing all of the items that caused water damage in the first place.
Special thanks to Matt Roach of SunsetCG for providing the photos and information about the repair process for these three case studies.
Author: Reuben Saltzman, Private Eye Moisture Testing
While real estate web sites give the most important information about homes to potential buyers, there are many other free web sites that give public information about homes in Minnesota. I use these sites on a regular basis, especially when I'm inspecting a flipped house. Not only is it interesting to see if permits have been pulled for work being done, but it's also interesting to see if the work has ever been inspected and approved.
I think it's wise to check the permit history when buying a home. The standard Seller's Property Disclosure Statement asks the seller if appropriate permits were pulled for any work performed at the property, but I think this is a fairly worthless question, and I often find the check boxes on this form just left blank.
If permits were pulled, it means the seller was given permission to perform work. It doesn't mean the work was completed, inspected, or approved. If you were buying a home, wouldn't you want to know if there were a bunch of open permits? Or that the basement was completely finished without permits? Or that no permits were pulled for a bunch of hack wiring that was done as part of a kitchen remodel?
The old timey way to check permit history was to call the building inspections department, but today there are at least eighteen cities in the Twin Cities metro area that give building permit history online. If I missed any, please let me know and I'll add them. I also have these cities listed under the "External Links" page on our web site.
*Minneapolis and several other communities use state electrical inspectors, so electrical permits must be looked up here: https://secure.doli.state.mn.us/etrakit2/AdvPermitSearch.aspx
Currently, only Minneapolis and Saint Paul have TISH evaluations publicly available online. Here's how to look them up.
Minneapolis: Go to the Minneapolis Development Review site to look up information about properties within the city. Just type in the house number and street name; don't bother with things like "Avenue" or "East." If there are multiple listings for your search terms, you'll be given a choice. Once you've found the property, click "View this Property".
The next page will have a bunch of links at the top left, including one that says "Truth in Sale of Housing". Click this link to look up any current TISH evaluations. If there are open repair orders, those will also be listed here.
Saint Paul: Go to the Saint Paul One Stop page to look up property information about Saint Paul homes. For TISH evaluations, start by clicking the link that says "Property info and Permits by Address." Type in the house number and street name, hit submit, and you'll be taken to the property info page. To know if there is a TISH evaluation on file for the property, look for an entry that says "Truth In Sale of Housing Inspection".
At the bottom of such an entry should be one or two hyperlinks; one linking to the TISH cover sheet, and another linking to the 'guts' of the report... or in same cases, both the cover page and the guts may be combined into a single report. I've heard some guys have figured out a way to combine the two reports into a single document, but I haven't.
The Hennepin County web site gives information about who the current owner is, what the property last sold for, aerial photos, and rough diagrams showing the sizes and shapes of lots. The image below gives a shrunk-down example of what this looks like. Click the photo to see a large version.
Hennepin County's property information site is the only one I use with any regularity, but other counties give similar information on their sites.
As of January 1st of 2014, there are new requirements for home sellers in Minnesota regarding radon disclosure. The old disclosure form that home sellers would fill out just asked if there were any environmental concerns with radon, and the sellers would check yes or no. It couldn't get any more basic.
If the home hadn't been tested for radon, the answer would of course be "no". End of story.
The new Minnesota Radon Awareness Act requires sellers to give home buyers a lot more information about radon, including whether or not tests have been performed, the most recent test results, any details pertaining to radon reduction or mitigation systems, a warning about radon, and a copy of the Minnesota Department of Health publication titled "Radon in Real Estate Transactions".
Whew. That's a lot of stuff. Here's what the radon section in the new disclosure form looks like:
With the new Radon Awareness Act, radon testing in Minnesota is going to become much more common in real estate transactions. In 2013, my company conducted radon tests at approximately one out of every three buyers inspections that we did; the number will probably increase to at least one in two for 2014.
If you're buying a home, hire a professional to test it for radon. Don't go with the sellers results. I had an almost comical situation occur this fall when a buyer hired us to conduct a radon test along with our home inspection. The seller acted very insulated because she had already conducted a radon test on her own, "proving" that radon levels in her home were low. After some conversation with the seller, it seemed quite obvious that she had placed the do-it-yourself test on the second floor of her home and the windows were probably open when she conducted the test, making the test results worthless. It was no surprise to us when the radon results came back high.
To test your own home for radon, simply purchase a do-it-yourself test kit and follow the instructions. Short-term tests can be purchased online for $7.95 at http://www.radon.com/sub/mn/. Don't bother calling a home inspection company like us; our tests are geared for real estate transactions, where the testing needs to be done quickly by a third party professional.
Click these links for more information:
Author: Reuben Saltzman, Structure Tech Home Inspections