Transite asbestos was a common product used to vent gas appliances such as furnaces, boilers, and water heaters in older homes in Minnesota. This material is no longer used because the interior of the vent can deteriorate and flake apart, collapsing in on itself. That, and it contains asbestos. Once the interior of the flue deteriorates it can get blocked, causing hazardous exhaust gases from the appliance to vent back into the home, rather than be carried to the exterior.
The photos below show a transite asbestos chimney flue liner found during an inspection of a 1955 built home in Columbia Heights. The top of the flue liner had fallen off the chimney, and the interior had collapsed in on itself, causing the water heater to backdraft. This first photo shows what the chimney looked like from the roof.
I had to bring a ladder onto the roof to get to the top of the chimney to get a look down the section on the far right.
Here's the top section of the transite flue liner that had fallen off of the chimney.
Here's another shot looking at the top of the chimney.
Here are a couple of shots looking down the flue.
As you can see in the photo above, the interior had flaked apart and completely blocked the flue. When the happens, the exhaust gases can't escape, so they go back into the home. There was heavy rust staining on top of the water heater, which is a telltale sign that the water heater backdrafts. It doesn't get much more obvious than that.
This fix is to leave the transite asbestos material in place, block the openings at the top and bottom of the chimney, and replace the water heater with either an electric unit or a powervent unit that can vent out the side of the house.
When buying a home with a transite asbestos flue liner / vent, be sure to have the interior of the flue inspected. If it's in pristine condition, as some of them still are, just plan to not use it again once the gas appliances that are connected to it are replaced. If the flue is deteriorated, have it abandoned immediately for safety. An HVAC contractor can help to figure out a different way to vent the existing appliances, or can replace the existing appliances with new ones that don't need to use the transite asbestos flue.
For anyone curious about what other transite asbestos flues looks like, check out the photo gallery below. These are all transite asbestos flues that I've found while inspecting older homes, mostly in Minneapolis. In each case, it's that white stuff.
Author: Reuben Saltzman, Structure Tech Home Inspections
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.
That's a quote from ASHI Certified Inspector John Bouldin, Ph.D, in the May issue of the ASHI Reporter. I've already blogged about the importance of strong guardrails at decks, and I've blogged about the importance of properly attaching a deck to the house, but I need to revisit that last topic. After attending an excellent seminar at Inspection World by John Bouldin on deck inspections, I have a little more information to share about one of the more common deck construction defects that home inspectors come across on a regular basis.
Decks typically shouldn't be attached to cantilevered floors*.
The image above comes from the Prescriptive Residential Wood Deck Construction Guide. The problem with attaching a deck to a cantilevered floor is that there is nothing below the cantilever (overhang) to keep the rim joist at the house from pulling loose; there is no support below it. John Bouldin had some excellent diagrams illustrating exactly why this is so important and exactly how this connection can fail, and was kind enough to share them with me.
This first diagram shows a traditional deck connection. The deck joist is at the far right, which is connected to a metal joist hanger, which is nailed into the deck ledgerboard. The deck ledgerboard is connected to the house with lag screws, which are attached to a 1" engineered rim board. The rim board is fully supported below by either a wall or a foundation. That's good stuff. That's how it should be done.
This next diagram shows a cantilevered connection. Everything in this diagram is pretty much the same, except the floor of the house is now cantilevered. The rim board for the house is no longer supported from beneath.
What happens when the rim board has no support? It can fail. The animation below shows how this can happen.
If there was support directly below the rim board for the house, this couldn't happen. That's why attaching a deck to a cantilevered floor is generally a bad idea. When a deck is built around a cantilevered section of the house, the most common way of supporting it at the house is to have the floor framing headered off, as shown in the diagram below.
If this is done, just be sure that the ledgerboard is large enough to support the added weight. The two photos below show an example of a deck that was headered off at the patio door, but all of the weight was concentrated to a tiny little piece of wood that you could hardly call a ledgerboard, and was simply nailed to the house. I made a big stink about this.
The fix for this particular deck was to have posts installed near the house.
*Of course, there are always exceptions; sometimes it's perfectly fine to attach a deck to a cantilever. If someone went out of their way to make this connection more secure by installing upside-down joist hangers at the house and the framing consisted of all dimensional lumber, it would probably work fine. As a home inspector, I usually don't get to see those details though. That's why I raise concerns over these types of connections while conducting deck inspections.
Author: Reuben Saltzman, Structure Tech Home Inspections
After writing a blog post about leaking temperature and pressure relief (TPR) valves at water heaters, I learned that this particular issue seems to completely befuddle folks. In the two years that I allowed comments, that post received 245 comments, including my own. The majority of the comments were questions from readers who were trying to troubleshoot their own leaking TPR valves.
I spent so much time responding to questions on that one blog post alone that I finally disabled comments on blog posts over 90 days old. Responding to reader comments on old blog posts was turning into a part-time gig for me.
The good news is that while answering reader questions, I ended up doing a fair amount of research to help myself understand problems that people were having, and to make sure that the advice I was giving was correct. The purpose of this blog post is to give some troubleshooting advice to people with leaking TPR valves.
All water heaters are equipped with a temperature and pressure relief valve. This valve will allow water or steam to escape from the water heater if the temperature or pressure gets too high; these valves are set to open when the pressure reaches 150 psi, or when the temperature reaches 210 degrees fahrenheit. This prevents water heaters from exploding or turning into missiles.
The rest of this blog post is going to be about troubleshooting a leaking TPR valve. If a TPR valve leaks, either it's defective or it's not. If it's not defective, it's leaking because the temperature was too high or the pressure was too high. In other words, a leaking TPR valve indicates one of these things: a defective valve, excessive pressure, or excessive temperature.
As I mentioned earlier, the TPR valve on a water heater is set to go off at 150 psi, or 210 degrees Fahrenheit. These numbers will be printed right on the valve, or on a tag attached to the valve. See below.
If a pressure relief valve for a boiler is accidentally installed on a water heater, it will leak like crazy from the start. These valves may look identical, but they're set to go off at 30 psi, not 150 psi.
If the proper valve is installed and it leaks, go on to step 2.
As I mentioned in my original post about leaking TPR valves, an easy troubleshooting step is to replace the leaking valve. TPR valves cost less than $15 and they're fairly easy to replace. If you're not sure how to go about doing this, hire a plumber. If you're trying to do this on the cheap because you can't afford a plumber, search YouTube for videos of "relief valve replacement". You'll find a ton of 'em there.
If a new, proper TPR valve leaks, it's probably just doing its job. It's relieving excessive temperature or pressure. The next step is to figure out which one it is.
This one is pretty simple. Run some hot water at a plumbing fixture and take a temperature reading with a meat thermometer. Make sure there are no tempering valves installed between the water heater and the faucet; whole-house tempering valves are typically installed at the water heater, and look like the type shown in the photo below, which I used in my blog post about safe water temperatures. If one of these valves is installed, the temperature you'll get at the faucet will be less than the temperature inside the tank, by design.
New single handle bath tub faucets installed in Minnesota since 2013 also require tempering valves (http://www.structuretech1.com/2013/04/new-safety-requirements-for-bath-tub-faucets-in-minnesota/). Those valves are typically installed below the bath tub, but can sometimes be found near the water heater.
For the record, a safe temperature for water coming out of faucets is 120 degrees. Temperatures in the 150 degree range are downright dangerous and in need of attention, but still wouldn't explain a leaking TPR valve. Temperatures really need to approach boiling to set off a TPR valve. This is extremely unlikely, but I suppose it is a possibility.
If the pressure in the plumbing system exceeds 150 psi, the TPR valve will leak. Getting to the bottom of this issue should be quite simple and straightforward. Buy a pressure gauge with an extra indicator to show surges, and connect it to the plumbing system. It doesn't matter if it's connected to a hot or cold water pipe, because both will be at the same pressure.
The easiest way to do this is to get a gauge with a garden hose thread, connect it to an outside garden hose faucet (sillcock), and open up the faucet. You should expect the pressure to be somewhere in the 40 - 80 psi range, with no other water running. If the pressure is over 80 psi, it should be corrected. The solution is to have a pressure regulator installed. Get a plumber to do that.
If the pressure is within the acceptable range, you play the waiting game. Once the temperature and pressure relief valve at the water heater leaks, go check the pressure gauge. If the 'surge indicator' shows something at or near 150 psi, the problem is excessive pressure. Excessive pressure is typically the result of a closed system; the water heats up and expands, but it doesn't have anywhere to go, so the relief valve does it's job and relieves the pressure. The solution, as I mentioned in my original blog post (http://www.structuretech1.com/2012/01/leaking-relief-valve/), is to install an expansion tank. If an expansion tank is already installed and there is still a problem with excessive pressure, either the expansion tank is not installed properly or it's not charged properly.
I may write another post later this year on solving excessive pressure, because that seems to be the most common problem that people deal with.
Author: Reuben Saltzman, Structure Tech Home Inspections
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