Radon mitigation is any process used to reduce radon gas concentrations in the breathing zones of occupied buildings, or radon from water supplies. Radon is a significant contributor to environmental radioactivity. Mitigation of radon in the air is accomplished through ventilation, either collected below a concrete floor slab or a membrane on the ground or by increasing the air changes per hour in the building. Treatment systems using aeration or activated charcoal are available to remove radon from domestic water supplies. Because high levels of radon have been found in every state of the United States, testing for radon and installing radon mitigation systems has become a specialized industry since the 1980s. Many states have implemented programs that affect home buying and awareness in the real estate community, however, radon testing and mitigation systems are not generally mandatory unless specified by a local jurisdiction.
According to the EPA’s “A Citizen’s Guide to Radon, the method to reduce radon “primarily used is a vent pipe system and fan, which pulls radon from beneath the house and vents it to the outside”, which is also called sub-slab depressurization, soil suction, or active soil depressurization. Generally, indoor radon can be mitigated by sub-slab depressurization and exhausting such radon-laden air to the outdoors, away from windows and other building openings. EPA generally recommends methods that prevent the entry of radon. Soil suction, for example, prevents radon from entering your home by drawing the radon from entering your home and venting it through a pipe, or pipes, to the air above the home where it is quickly diluted and EPA does not recommend the use of sealing alone to reduce radon because, by itself, sealing has not been shown to lower radon levels significantly or consistently according to the EPA’s “Consumer’s Guide to Radon Reduction: How to fix your home.
Ventilation systems can utilize a heat exchanger or energy recovery ventilator to recover part of the energy otherwise lost in the process of exchanging air with the outside. For crawl spaces, the EPA states, An effective method to reduce radon levels in crawlspace homes involves covering the earth floor with a high-density plastic sheet. A vent pipe and fan are used to draw the radon from under the sheet and vent it to the outdoors. This form of soil suction is called sub-membrane suction, and when properly applied is the most effective way to reduce radon levels in crawlspace homes.”
The most common approach is the active soil depressurization(ASD). Experience has shown that ASD is applicable to most buildings since radon usually enters from the soil and rock underneath and mechanical ventilation (MV) is used when the indoor radon is emitted from the building materials. A less common approach works efficiently by reducing air pressures within cavities of exterior and demising walls where radon emitting from building materials, most often concrete blocks collect.
In hot, humid climates heat recovery ventilators (HRV), as well as energy recovery ventilators (ERV), have a record of increasing indoor relative humidity and dehumidification demands on air conditioning systems. Mold problems have originated in homes that have been radon mitigated with HRV and ERVs have an excellent record in heating climates.
A recent technology is based on building science. It includes a variable rate mechanical ventilation system that prevents indoor relative humidity from rising above the present level such as 50% which is currently suggested by the US Environmental Protection Agency and others as an upper limit for the prevention of mold. It has proven to be especially effective in hot, humid climates. It controls the air delivery rate so that the air conditioner is never overloaded with more moisture than it can effectively remove from the indoor air.
It is generally assumed that air conditioner operation will remove excess moisture from the air in the breathing zone, but it is important to note that just because the air conditioner cools does not mean that it is also dehumidifying. If it is 14 degrees or less, it may not dehumidify at all even though it is cooling.
Factors that are likely to aggravate indoor humidity problems from mechanical ventilation-based radon installations are as follows and an expert radon mitigation/building scientist will check for and correct any and all of the following when he or she performs radon mitigation procedures:
Air conditioner duct leaks located outside the breathing zone, such as in the attic.
Excessive exhaust fan operation
Oversized or over-capacity air conditioners
AC air handler fans do not stop running when the air conditioner compressor stops running.
Delta, which is the amount that the air-cooled as it is passed through the air conditioner’s cooling coils. A good delta performance figure for home air conditioners is about 20F in comparison, automobile air conditioners deliver delta performance of 32 to 38f. A delta of 14f will dehumidify poorly if at all.
These are useful to see if further testing is warranted. Most are activated charcoal-based or use electret ion levels for two to seven days. You can mail your tests to a lab for the results. Short-term tests are available at home centers, hardware stores, and online retailers.
Long-term radon tests:
These radon tests measure levels for 90 days to one year. Most, such as the Airthings Corentium Home Model – Digital Radon Detector test, is based on alpha particle tracking. This is a more accurate indicator of average annual levels, which can vary significantly from day to day and month to month based on factors such as a drop in air pressure, gusty winds, variable soil moisture, and snow cover, which traps radon gases. Long-term radon tests are available through state radon agencies and online retailers.
Continuous radon tests:
Electric monitors, such as the Airthings Corentium Pro Digital Radon Monitor, Portable. These can be used for both short-term and long-term testing to give you a running average every day.
When an initial short-term test registers 4 pCi/l or higher, the EPA recommends doing a 2nd radon test. A long-term test will give you the most accurate information, but the short-term test is acceptable if you need the results quickly, such as for a real estate transaction, or your first levels registered 8 pCi/l or higher. If a second test registers about 4 pCi/L, consider taking steps to reduce radon levels in your home, the EPA cautions. If your home has high levels of radon, you can start by trying these easy repairs to reduce radon levels. These efforts alone rarely reduce levels significantly, but if your level is only slightly elevated, these repairs might make a difference. They will also make out her radon reduction methods more effective and cost-efficient
Caulk foundation cracks, construction joints, and other openings with polyurethane caulk.
If you have a sump pump, install an airtight cover on it (choose one that allows access to your sump).
Cover soil in crawl spaces with polyurethane plastic sheeting ( with a minimum thickness of 6 mils, available at home centers) tightly attached to the walls.
You can also try sealing concrete, although the EPA has found concrete sealers to be a temporary solution at best.
Once you’ve tackled this, retest the home. If levels are still high, consider contacting a pro.
As a seller, many people think that only the home buyer has a home inspection upon buying the home. However, a seller can benefit from a pre-listing inspection because it avoids unnecessary problems down the road. If you’re selling your home, consider getting pre-listing home inspection services. You may be surprised to learn that about 35% of our home inspections are sellers’ inspections.
How Does a Pre-Listing Inspection Work?
Normally, the pre-listing inspection is performed before the home is listed on the market. This allows prospective buyers to see the condition of the home before negotiations being made. Having the inspection performed after negotiations can cause all kinds of issues on the part of the buyer, so it’s easy to see how this kind of inspection can benefit everyone involved.
The inspector will provide a typical inspection and create a report, and as the seller, you will also have a summary-page overview prepared for easy reference. The seller or with a real estate agent then review the report and/or summary-page for approval, and may choose to adjust the listing price or other factors. Then, both the report and overview are published and available to real estate professionals and prospective buyers.
What Are the Benefits of a Pre-Listing Inspection?
As we said before, the benefits are numerous. Being upfront about the condition of the home will help to eliminate conditional offers or issues with negotiations, resulting in the seller having to sell the home more than once because the buyer has changed their mind. Everything is agreed upon before the listing is published and the home goes on the market, which minimizes the liability for all parties.
On top of this, if the home is found to be in better condition than originally thought, the price can reflect this. The buyer is also more likely to make an offer without their inspection because one has already been performed, which can increase the speed at which the house is sold and changes hands. There will be no conflicting information making the transaction complicated—just peace of mind for everyone, and a smoother, quicker process where everyone wins.
If you’re selling your home, we highly recommend considering a pre-listing inspection to make your sale as quick and easy as possible. Thornton Home Inspections offers Pre-Listing (Sellers) inspections as one of our home inspections services. For more information just call 423-414-3009/706-250-6218 or schedule online
Thank you to all that voted for Thornton Home Inspections as the Chattanooga Times Free Press’ 2018 Best of the Best!
We are honored by the nomination and winning this award. We constantly strive to provide the best customer service and home inspection services that our area has to offer and we thank each of our clients and partners for deciding we were the best.
Here at Thornton Home Inspections, we pride ourselves in thorough home inspections. If we find that a home has major issues, we are going to let you know, even if that delays a purchase/sale. Honesty and integrity are very important to us. Therefore, we develop relationships with our clients, not real estate agents. We want you to know we are working for you and not them. They are interested in the sale, but we are interested in informing you about your potential investment.
Follow these links for more information on our services:
Why get a home inspection when buying an “as is” home?
Answer:
Some sellers – often, those working without an agent – want to sell their home “as is” so they don’t have to invest money fixing it up or take on any potential liability for defects. There is nothing wrong with buying a home “as is,” particularly if you can buy it at a favorable price, but if you are considering buying an “as is” home, you should still hire a competent home inspector to perform an inspection. There are several reasons for this.
First, you don’t know what “as is” is. Sure, you can walk through the home and get an idea of its general condition. You may even spot some defects or items in obvious need of repair. But you won’t obtain the same detailed information you will receive if you hire a home inspector. Home inspectors are trained to look for things you are not likely to notice. InterNACHI inspectors, for example, must follow InterNACHI’s Residential Standards of Practice and check the roof, exterior, interior, foundation, basement, fireplace, attic, insulation, ventilation, doors, windows, heating system, cooling system, plumbing system, and electrical system for certain defects. Armed with a home inspector’s detailed report, you will have a better idea of what “as is” means regarding that home, which means you’ll be in a better position to know whether you want to buy it. You may also be able to use information from the home inspection to negotiate a lower price.
Second, many states require the seller to provide you with written disclosure about the condition of the property. Sellers often provide little information, and a few even lie. A home inspection can provide the missing information. If an inspector finds evidence that a seller concealed information or lied to you, that may be a sign that you don’t want to buy a home from that seller.
Finally, if you buy a home “as is” without hiring a home inspector and then later discover a defect, all is not lost. A home inspector may be able to review the seller’s disclosure and testify as to what the seller knew or should have known about. The inspector may find evidence that the seller made misrepresentations or concealed relevant information from you. Even the seller of an “as is” home may be held liable for misrepresentation or concealment.
But the better choice, obviously, is to hire a home inspector first. Remember: The cost of a home inspection is a pittance compared to the price of the home. Be an informed consumer, especially when buying an “as is” home, and hire an InterNACHI Certified Professional Inspector®.
Double-paned window condensation can be a problem here is why.
Condensation is the accumulation of liquid water on relatively cold surfaces.
Almost all air contains water vapor, the gas phase of water composed of tiny water droplets. The molecules in warm air are far apart from one another and allow the containment of a relatively large quantity of water vapor. As the air cools, its molecules get closer together and squeeze the tiny vapor droplets closer together, as well. A critical temperature, known as the dew point, exists where these water droplets will be forced so close together that they merge into visible liquid in a process called condensation.
Double-pane windows have a layer of gas (usually argon or air) trapped between two panes of glass that acts as insulation to reduce heat loss through the window. Other types of gas used in this space have various effects on heat gain or loss through the window. Some windows also have a thin film installed between panes that separates the space between the panes into two spaces, further reducing heat loss and heat gain through the window. If multiple-pane windows appear misty or foggy, it means that the seal protecting the window assembly has failed.
Silica Desiccant
A desiccant is an absorbent material designed to maintain dryness in the space it protects. In a double-paned window, silica pellets inside the aluminum perimeter strip absorb moisture from any incoming air that enters the space between the panes. If not for the silica desiccant, any moisture in the space between the panes would condense on the glass as the glass cools below the dew point temperature.
Silica gel has an immense surface area, approximately 7,200 square feet per gram, which allows it to absorb large amounts of water vapor. As the sealant protecting this space fails over time, increasing amounts of moisture-containing air will enter the space between the panes, and the silica pellets will eventually become saturated and will no longer be able to prevent condensation from forming. A double-paned window that appears foggy or that has visible condensation has failed and needs to be repaired or replaced.
Why Double-Paned Windows Fail: Solar (Thermal) Pumping
Although double-paned windows appear to be stable, they actually experience a daily cycle of expansion and contraction caused by thermal pumping. Sunlight heats the airspace between the panes and causes the gas there to heat up and expand, pressurizing the space between the panes. At night, the window cools and the space between the panes contracts. This motion acts like the bellows of a forge and is called thermal pumping.
Over time, the constant pressure fluctuations caused by thermal pumping will stress the seal. Eventually, the seal will develop small fractures that will slowly grow in size, allowing increasing amounts of infiltration and exfiltration of air from the space between the panes.
Failure Factors
Windows on the sunny side of a home will experience larger temperature swings, resulting in greater amounts of thermal pumping, seal stress, and failure rates.
Vinyl window frames have a higher coefficient of expansion resulting in greater long-term stress on the double-pane assembly, and a higher failure rate. Windows also experience batch failure, which describes production runs of windows, especially vinyl windows, that are defective, meaning that the pane assemblies have been manufactured with seals that have small defects that will cause the window to fail prematurely.
The Nature of Damage
If it’s allowed to continue, window condensation will inevitably lead to irreversible physical window damage. This damage can appear in the following two ways:
river bedding. Condensed vapor between the glass panes will form droplets that run down the length of the window. Water that descends in this fashion has the tendency to follow narrow paths and carve grooves into the glass surface. These grooves are formed in a process similar to canyon formation.
silica haze. Once the silica gel has been saturated, it will be eroded by passing air currents and accumulate as white “snowflakes” on the window surface. It is believed that if this damage is present, the window must be replaced.
Detecting Failure
Condensation is not always visible. If the failure is recent, a failed window may not be obvious, since condensation doesn’t usually form until the window is heated by direct sunlight. Windows in the shade may show no evidence of failure, so inspectors should disclaim responsibility for discovering failed double-paned windows.
Thermal Imaging as a Detection Tool
Under the right conditions, it’s possible to use an infrared (IR) camera to detect failed windows. IR cameras are designed to record differences in temperature.
Recommendations for Failed Windows
According to industry experts, the glazing assembly can be replaced approximately 75% of the time. Occasionally, the sashes must be replaced, and only about 5% of those cases require that the entire window be replaced.
Inspectors should be aware that there are companies that claim to be able to repair misty windows through a process known as “defogging.”
This repair method proceeds in the following order:
A hole is drilled into the window, usually from the outside, and a cleaning solution is sprayed into the air chamber.
The solution and any other moisture are sucked out through a vacuum.
A defogger device is permanently inserted into the hole that will allow the release of moisture during thermal pumping.
Inspectors should know that there is currently a debate as to whether this process is a suitable repair for windows that have failed, or if it merely removes the symptom of this failure. Condensation appears between double-paned windows when the window is compromised, and removal of this water will not fix the seal itself. A window “repaired” in this manner, although absent of condensation, might not provide any additional insulation. This method is still fairly new and opinions about its effectiveness range widely. Regardless, “defogging” certainly allows for cosmetic improvement, which is of some value to homeowners. It may also reduce the potential for damage caused by condensation in the form of mold or rot. Some skepticism exists about the effectiveness and cost-effectiveness of this method of repair.
In summary, condensation in double-paned windows indicates that the glazing assembly has failed and needs repair or replacement. Visible condensation can damage glazing and is the main indication of sealant failure.
Client Speaks:
I highly recommend Thornton Home Inspections! All inspections have been stellar; this is the third inspection that they completed for me. We scheduled it in less than two days. Desmond arrived on time, thoroughly inspected the home from top to bottom, provided helpful pictures with explanations, and followed up with a detailed report. He also linked me to helpful companies should I need repairs. I feel like I have a partner for future home purchases and upgrades to my present home. Great Job – excellent value for the price.
– Paula Jeffery Desmond Thornton and his team of professionals provided this first-time homeowner an ideal customer service experience. Inspection was for a home in Cleveland, Tennessee. I received the report on the same day as the inspection. Desmond was my inspector and he provided a detailed and thoughtful report with pictures and diagrams to help me understand the inspection. I was welcomed to join him during the inspection but was unable to, so his detailed report and a warm welcome to call him for further clarification, if needed, at a later time gave me reassurance and peace of mind. Thank you Desmond!
– Audra Highley
Thornton Home Inspections provides the most complete and responsive service we have ever encountered. We have had many inspections done on other homes and his patience, knowledge, and efficient methods are amazing. Hire this GREAT service provider!!!
– Barbara Martin
Arranging for a home inspection is one of the biggest investments you can make in your property. As with all investments, there are good ones and bad ones. If you want to make sure that your home inspection pays off, here are 5 mistakes to avoid.
1. Not researching the home inspector
Let’s face it, if you were going to invest money on the stock exchange, you wouldn’t just go to any broker. You would do some research to make sure that your broker will invest your money wisely. The same is true with a home inspector. Make sure that he is highly qualified and comes with solid recommendations and is a member of a recognized home inspectors’ association.
2. Not being at the inspection
Even though you might not understand everything said during the inspection, it’s important to be at your home inspection. This will give the inspector a chance to explain certain things in the report. He may have to ask you some questions regarding certain features of your home.
3. Not reading the report
This may not be your fault because some home inspectors write up complicated reports full of industry jargon. However, you need to take the time to thoroughly read through the report. When looking to hire a home inspector, look for samples of previous reports to find one who writes in a clear and concise way.
4. Not arranging a pre-sale inspection
Before selling your home, it’s important to have a presale inspection carried out. This will give you enough time to fix up anything needing to be done in the home and in the end you will get top dollar for your property.
5. Not preparing the home
Home inspections can take a long time; therefore make it as easy as possible for the home inspector to gain access to all areas of the home. If there are repairs that need to be carried out, make sure and hire a professional. This will reduce the need for repeat inspections in the future.
As a seller, many people think that only the home buyer has a home inspection upon buying the home. However, a seller can benefit from a pre-listing inspection because it avoids unnecessary problems down the road. If you’re selling your home, consider getting pre-listing 
On top of this, if the home is found to be in better condition than originally thought, the price can reflect this. The buyer is also more likely to make an offer without their inspection because one has already been performed, which can increase the speed at which the house is sold and changes hands. There will be no conflicting information making the transaction complicated—just peace of mind for everyone, and a smoother, quicker process where everyone wins.
If you’re selling your home, we highly recommend considering a pre-listing inspection to make your sale as quick and easy as possible. Thornton Home Inspections offers Pre-Listing (Sellers) inspections as one of our 
Thank you to all that voted for Thornton Home Inspections as the Chattanooga Times Free Press’ 2018 Best of the Best!
