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Absolutely home buyers should be concerned about molds in their prospective home. Especially when a good home inspector informs them that there are conditions in the house that may produce future out breaks of mold. Maybe there is a bargain to be had in the real estate transaction. A possible diamond in the rough provided the savvy buyers can identify the causes of the mold and prevent future outbreaks.
Lets start at the beginning.
The public image of mold is often misleading and far from the truth. And yes, certain molds are toxic to humans especially if the individual is sensitive or allergic to molds. However, keep in mind that molds are a large class of organisms that serve a very important function in the environment – they decompose and break organic matter as part of the nutrient cycle. They break down fallen leaves from trees and other detritus. Think of the mold that magically appears and grows on our bread if left uneaten for too long.
Molds are ubiquitous. They can be found in our cars, between our toes, the spores can be found floating in the air. The key to mold growth in our homes is a source of moisture and organic matter and humid environment, anything over 65% humidity will support mold.
Where are molds most commonly found in the home?
In short, mold can be found anywhere in the home provided there is a constant source of moisture, poor ventilation situation and organic surface for mold to feed on. It is even possible for mold to grow on dust covered surface where mold feeds on the dust.
Molds are often found in bathrooms because we have a source of moisture when we shower, a condition for poor ventilation and hence the humidity especially in the winter when we close the windows to keep the heat inside. And, we have a source of organic matter – the drywall, particularly around the ceiling because hot humid air tends to rise and hangs out at the ceilings when there is a lack of proper ventilation. Bathrooms are required to have either a window accessible to the exterior or mechanical ventilation to the exterior with a minimum of 50 cubic foot per minute (cfm) exhaustion. It is highly recommend that after a shower, to leave the bathroom exhaust fan on for about 30 minutes to complete vent the humid air to the exterior. A simple timer installed on the exhaust fan will handle that.
Other common areas to find mold is the basement or crawl spaces and attic spaces. The scent of musky dampness is a very good indicator that the environment has poor ventilation and highly likely will have mold somewhere. Often mold is growing behind wood panels, organic surfaces near the floor where the moisture is highest. In the attic, mold will grow right on the wood framing member and roof sheathing.
What all these places have in common is they have poor ventilation and a source of moisture. Basements and crawlspaces are often damp to begin with. The moisture comes from the ground as the foundation is made of cement which is porous. Efflorescence is a good indicator that moisture has moved from inside the cement and onto the surface of the cement. Attics with improper vent discharges often will result in mold growth. For example, bathroom vents, kitchen vents and even dryer vents can be improperly installed to discharge into the attic space instead of directly to the exterior. These vents exhaust moist indoor air supplying the attic with enough moisture to to support mold growth.
Mold is also commonly found in rooms that have an exterior wall where it can be cold during the winter season with insufficient or missing insulation. When the heat is turned on, warm air passes over the cold surface, often the cold corner of a room where the ventilation is poor, the warm air forms condensation on top of the cold surface. This provides enough moisture to support mold growth around those cold corners of the room. To remedy this is simple, ventilate the room. Make sure enough air is circulating the room and insulate the attic and exterior walls to rid the house of those cold corners.
What you should know to get rid of mold in the house.
A good home inspector will be able to explain in detail and in layman terms to their clients what they need to know about mold should the buyers wish to continue with the real estate transaction. What can be done? – depends on the extent of the damage. First, address the root cause. Where is the moisture coming from? Eliminate the source of moisture. Next remove and replace all affected building materials. Ensure there is adequate ventilation in the new construction.
If the extent of the damage includes structural members, this is where it is having such information is priceless as prospective buyer can determine financially if they which of continue, renegotiate the price or walk away from the real estate transaction. If the home buyer decides to proceed with the purchase, they should be fully aware of the risks involved. A good home inspector needs to explain in laymen terms the implications of the risk factors noted. Every risk factor requires a detail explanation to the client.
If you trace back to the root cause of most damages around the house, they almost always leads back to water damage. This blog discusses where water damage occurs in the house and how we can manage water damage around the house. This is important because good water management around the house can prevent water damage around the house which can potentially cause structural and health problems.
Ideally, the house should be build on top of the highest grade compared to the surrounding to allow water to drain away from the foundation on all four sides. The grade around the house should slope 1 inch down for 12 inches horizontal for at least 6 feet away from the house. If the house is built on poor grading, such as next to a hill or at the bottom of a hill where water can run down towards and accumulate at the foundation, you can expect water issues around the house. Water proofing the foundation walls is a must in these situations. Also, it is recommended that trenches be installed to divert runoffs away from the foundation of the house in order to avoid hydro static pressure building up around the foundation. Should there be cracks in the foundation, water will enter the house through the cracks if there be enough hydro static pressure from the sides or under the foundation.
The are 4 main strategies to reduce the risk of water damage around the house. 1) reduce rain water entry from sky and ground. This means controlling rain and snow melt with overhangs, proper flashing, gutters and downspouts to divert the water away from the foundation. 2) control the temperatures of condensing surfaces by insulating to increase the R-value of that part of the house. 3) control unwanted air flows that carry moisture by sealing air leaks around the house. 4) Control moisture sources and indoor air pollutants with mechanical ventilation.
Where does all the unwanted water come from?
The exterior sources of water such as a leak in the roof or foundation can contribute. Leaks in flashings around roof and windows can also be source of unwanted water. Uninsulated air ducts can also be a source of unwanted moisture as water condenses on the cool surface, especially in the cooling season when the warm moist air comes in contact with a cool uninsulated surface of air ducts.
Water can also be wicked from concrete surfaces such as crawl spaces or foundations. This water source acts like a “pump” as moisture is wicked into the house, evaporated, exits the house via the stack effect only to draw more moisture from the foundation walls. A quick and easy test can determine where the water is coming from. Tape a 2 ft x 2 ft plastic sheet on the basement concrete for a few days, water droplets form on top of the plastic sheet, then moisture from inside the house is condensing on a the cool surface, if water droplets form under the plastic, moisture is moving from the concrete foundation into the house.
A family of 4 can produce 2-3 gallons of water from vapor just by breathing, washing, showering, cooking, and drying their clothes.
Why is all this moisture a problem?
The moisture in the air by itself is not a problem, in fact, it is comforting in the winter to breath humid air. The problem occurs during the coldest days of winter when that moisture condenses on cold surfaces around the house. Water is formed and if left unchecked, can cause damage to the surface and promote mold growth. These surfaces include wall sheathing, roof sheathing, window surfaces, poorly insulated walls and ceilings, insulated air ducts.
How to reduce water vapor.
Eliminate large sources that can be reduced or removed such as humidifiers, unvented combustion appliances, ground water evaporating from basement or crawlspace.
Use kitchen and bathroom exhaust fans to remove moist air from the house.
Provide controlled, continuous fresh-air ventilation. This gives effective dehumidification in cold weather.
Control the movement of vapor by using vapor retarders
Infrared thermal imaging is an awesome tool in electrical inspections. Best of all, it is safe for the inspector as we do not touch any electrical equipment during the inspection.
As we know, good infrared cameras are good at detecting heat differences in high precision. This means that the camera can identify and produce thermograms to show materials with very small temperature differences. This is great for detecting moisture damage around the house.
This is also a helpful and important feature when we inspection the electrical components of the house. The infrared camera is particularly good at detecting overloaded circuits and breakers. An overloaded circuit is protected by breakers that trip or fuses the blow when the current drawn is in excess of the rated breaker or fuse. What if the current is incorrectly protected with a higher amperage then what the wires are rated for? A common mistakes home owners make is using a 14 AGW with 20 A or 30A breakers. The breakers would not trip until the current drawn reached 20 A or 30 A depending on the breakers used. In the mean time, the 14 AGW copper wire is being heated as more current is being drawn then what the wire thickness can handle. The hazard here is the wire can melt the sheathing and worst, a potential electrical fire hazard.
If current was being drawn during the inspection, the infrared camera would pickup the heated wire. If left on long enough, the wire behind drywall can also be detected by the infrared camera. The infrared camera can also sense breakers working close to their rated limit. If detected, the breaker should be examined closer for possible causes. Some breakers with built in GFCI are warmer compared to regular breakers, in this case, if the built-in GFCI breaker was the same temperature as other breakers, then there would be a problem with the GFCI breaker.
Superman has the super power of “X-ray” vision which allows him to see behind walls or inside houses. Imagine if you have that power before you buy your next house? Read more about infrared thermal imaging and seeing behind walls.
What other defects and damages can infrared thermal imaging detect that is not visible to the human eye? Moisture! How is that possible you ask? Remember that infrared thermal images display temperature difference. The image produced is a thermogram displaying surface temperatures relative to one another.
So why does the drywall under the window clearly show a cooler temperature? Recall that blue is cooler compared to red or orange. If the temperature was not significantly different, we would not look further into this. The mostly like two reasons include missing insulation behind the drywall or the drywall is moist. We use a moisture meter to eliminate the moisture issue, leaving the missing insulation the most likely explanation. However, if the moisture meter indicates moisture, we inspect the window well and window still closer for signs of moisture damage. We always confirm with a moisture meter reading before concluding moisture damage.
If the moisture meter comes up positive and the window still shows moisture damage, depending on how long this condition has gone on for and whether the immediate area has good ventilation or not, this could be good conditions for mold growth if left unchecked. Also, behind the drywall would definitely be subject to mold conditions as ventilation is nil plus the ample moisture supply.
A quick scan with the Flir B-250 gives the home inspector an idea of where to investigate further. The scan is non-invasive and does not damage the walls or any other part of the house. This makes the inspection fast, accurate and provides clients with proof of defect or damage.
Ice damming is a roofing problem unique to northern climates in which the low pitched roofs form ice dams and trap water causing water damage to the roof sheathing and seepage into the building. There are several conditions that has to exist before ice damming occur. Freezing temperatures as already mentioned, a low pitched roof, and a worm attic. When snow falls and accumulates on the roof it may sit there for days. During the day, temperatures may rise above freezing and with the help of the sun, melt the snow which accumulates at the eaves of the roof. At night, temperatures drop below freezing and the melted snow forms an ice dam at the eaves of the roof. As the cycle repeats, the melted snow, now water, enters the roof sheathing. A warm attic accelerates the process.
What can home owners do to prevent ice dams? The atmospheric temperature cannot be controlled but factors around the house can be. Changing the pitch of the roof is not feasible. What is controllable is the insulation and leaks in the attic. Keeping a cold attic is key. Seal the attic leaks and add more insulation to keep the attic cold in the winter are critical steps to preventing ice damming.
Additional measures to help address ice damming include adding eave protection, waterproofing membrane, along the first 18-24 inches of the roof from the eaves. Another anti ice dam measure is the use of heating cables along the eaves. Often, home inspectors view heating cables as an indicator that the house has had ice damming issues in the past. Another indicator of past ice damming issues is pike ax damage marks on the shingles along the eaves. Venting from soffit vents to the roof vents helps keep the attic cold.
The damage ice dams can have on a house can be extensive and mysterious as the water seeps through the roofing shingles and sheathing, and may run along framing members. If undetected, damages can include moisture damage to drywall, ceiling, flooring and creating of an environment friendly to mold.
In winter, when warm air is vented directly into the attic, the moisture in the warm air will condense. Over a season, that can add up to a lot of moisture in your attic and that creates an ideal condition for mold. Furthermore, the roof sheathing start to cup and rot. The moisture can also run down the ceiling and into the drywall, and again, this creates an ideal environment for mold and rot.
So what is mold? Simply put, mold is a fungus found pretty much everywhere on this planet. Ever left food out and after a week or so, the food grows fuzz around it? That’s mold. Aside from food spoilage, molds are microbes involved in all natural material bio-degradation. This also includes building materials such as wood framing members, sheathing, and drywall.
Molds are ubiquitous. Mold spores are a common component of household dust. However, when mold spores are present in large quantities, they can present a health hazard to humans, potentially causing allergic reactions and respiratory problems.
There are thousands of species of molds, all requiring moisture to grow. In the ecosystem, their role is to decompose. The term “toxic mold” refers to molds that produce mycotoxins, such as Stachybotys chartarum.
Mold around the house is found in damp, dark or steamy areas such as bathroom or kitchen, cluttered storage areas, recently flooded areas, basement areas, plumbing spaces, areas with poor ventilation and outdoors in humid environments. In addition, attics particularly with vents that improperly discharge directly into the attic are prone to supporting mold. Often time when I inspect an attic, it is common see a bathroom vent or kitchen vent discharge directly into the attic, and the framing immediately around the vent discharge is covered in black mold.
The key for mold growth around the house, as already mentioned, is a damp environment and a lack of ventilation. For the average home owner, visible mold is relatively easy to spot if you know what you are looking for. However, when mold is hidden behind drywall, a panel, storage items, or behind furniture attached to the wall it may be difficult to identify.
Identifying mold is beyond the scope of a standard home inspection. A good home inspector can recognize conditions the would support mold growth and report that to the client. And, if home buyers expect to buy a home free and clear of any mold, then don’t buy any home because as mentioned above, mold is ubiquitous. They are in your cars, on your clothes, in your hair, on your skin so on. We cannot control their presence, we can only control the environment to limit their growth.
Back drafts are caused when the house is under negative pressure. A good sign the house is under negative pressure is when you open a door and it closes by itself behind you or if you open a window and a breeze blows in. Depending on the appliances you have operating in the house, back draft conditions may exist and occupants may be subject to carbon monoxide poisoning. CO is produced when you have incomplete combustion, when the fuel being burned does not have enough combustion air to completely burn the fuel. A common situation found during a home inspection is a furnace room being sealed up with dry wall without sufficient supply air. This situation is fine if the appliances in the the room is direct vented. That means the intake supply air and exhaust are piped directly to the exterior through the side walls. The appliances of concern include hot water tank or mid efficiency furnace which uses natural draft to vent the combustion exhaust, Natural draft appliances require the house to be under positive pressure to work adequately.
During a home inspection, experienced home inspectors look for the above conditions and note the potential hazard. In addition, some subtle situation the home owner may not be aware of include the dryer acting as an exhaust, a kitchen exhaust fan, a attic or whole house fan exhausting directly to the exterior, a chimney flue left open, which all can contribute to the house being under negative pressure preventing natural draft appliances from working properly.
Another subtle condition are the leaks in the ducts from the boot of the furnace to the jumper in the furnace room. All the leaks add up to the equivalent of having return vent near the blower motor. First, the return air should come from either the first floor or second floor but not in the basement as a rule of thumb. There is typically enough leaks in the duct works around the furnace to decrease the efficiency of the system about approximately 15%. The blower motor is strong enough to create a negative pressure environment in the furnace room and thus create back drafts in the natural draft vents. With a return vent close by or at the blower motor, a negative pressure environment is also created.
This my seem like a simple question. It is your house and shelves and cabinets are easy to build. What is the big deal? Why even ask such a question?
From the home inspector’s point of view, it depends. Generally, as home inspectors, we view shelves and cabinets secured to the walls of car garages as unsafe and not rated for load. Often we see home owners store items that may overload the shelves and thus create a hazardous condition.
Some home owners are correct to be concerned and should check with an expert before taking on such a simple project. The issue to be concerned with is structural safety and the load that shelves can take. The current home owner may be aware of these safety issues but as a home buyer moving into the home, they may not know what load the shelve and cabinets were rated for. A worst case scenario is that new owners move in and decide to store some tires on the shelves. The shelves may sage or fail and worst, compromise the framing of the garage and the house. The new home owners call up the home inspector and complains that they were not warned of this and threatens to take legal action.
So from a home inspector’s point of view, when asked about a simple project as putting up storage space in the garage can be a legal mess. And if the home owner insist on building such structures to the garage, I recommend they check with a structural engineer first to get proper drawing plans, building materials, and the proper skilled carpenter to build it.
I have the old furnace and old boiler systems. How can I tell if they are still safe to use this winter?Oct 21 2013
By the term ‘old’ we are referring to the natural draft appliances that burn natural gas or propane. These include furnaces and boilers that recently, TSSA has determined may result in carbon monoxide (CO) safety hazard in the home and may cause personal injury and even result in death.
The safe use of fuels used to heat our homes in Ontario falls under the Technical Standards and Safety Act, 2000. The Technical Standards and Safety Authority (TSSA) is designated by Ontario’s Ministry of Consumer Services to administer and enforce this Act.
CO is a colorless, odorless and tasteless gas produced when fuels such as natural gas and propane are incompletely burned. Common causes include poor maintenance of the appliance leading to incomplete combustion of the fuel and depressurization of the house causing back draft conditions in the house. The depressurization of the home is caused by other exhaust systems that prevent the natural draft to work properly. Other exhaust systems include dryer exhaust, kitchen or bathroom exhaust and wood fire place. Also, the upgrades to more efficient windows and doors limit the outside air infiltration into the home creating a ‘tighter’ environment.
The symptoms of CO poisoning include vomiting and nausea, burning eyes and dizziness, difficulty breathing, confusion and victims may also become unconscious. If CO is undetected in the home, occupants have been found dead in their sleep.
So how can you tell if the appliances are safe to use? Get them checked and maintained on an annual basis by a licensed gas technician. They will perform a CO safety check during the maintenance visit. Install CO detector in the house. The ideal location of it is not in the furnace room or anywhere near it. You want it working ideally on the second floor hall way so that there is early warning when CO is detected instead of waiting of it to travel from one room to the next if you installed it in one of the bedrooms.
For more information visit www.tssa.org
Infrared Thermography used in a home inspection can show the client defects around the house that no other home inspection method can. The technology is used in a variety of inspections around the house. The infrared camera can detect moisture damage around the house, these are environments ideal for mold growth. it can also detect cold spots or missing insulation in the attic, exterior walls or ceilings. Infrared thermography is also used to detect water leaks around the house, in the roof, and in the basement whether it is from a plumbing leak or from the exterior through the foundation walls. It is also used in electrical inspection and is used to detect overloaded circuits or defective breakers.