for October, 2013
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.