Throughout this I will highlight the different systems found in the attic, followed by the main problems home inspectors identify during the attic inspection. In order for the attic space to function well, the combination of insulation, ventilation and vapor barrier must work in harmony. However, it is all too common for one or more of these components to be flawed, which ultimately leads to any number of conditions.
The attic is also a space where other systems such as the structure, roof sheathing, electrical, heating and plumbing concerns can be discovered…which makes this space one of the most important areas of the home to investigate.
Structure – The roof and ceiling structure can be seen in the attic. Sometimes we discover that structural members are leaning, broken, rotting, split, sagging, cut or improperly installed. These are the issues that would warrant further investigation or repairs, depending on the specific situation.
Roof Sheathing – This is the main support for the materials that cover the roof, such as the shingles. We look at the sheathing to see if we can notice any leakage, water stains, wood rot or fungal staining. (Mold)
Electrical – It is not uncommon to see electrical wires running through the attic. We want to make sure that the wires have been properly secured to the structural members and out of the way. However, I see wires running in all sorts of directions laid out on the insulation and fully exposed. This can pose a serious fire hazard especially if rodents find and chew on the wires. Sometimes pot lights are covered with insulation, which could be a fire hazard if the lights are not containing the letters IC, which stands for insulated ceiling.
Heating – Chimneys and vents often run through the attic on their way up through the roof. Often, the connections are not secure or the fully discharging out through the sheathing. Metal chimneys could be rusted from condensation or missing a fire stop at the bottom.
Plumbing – Much like chimneys and heat vents, plumbing stacks run through the attic and on through to the outside. Home inspectors pay attention to plumbing stacks that discharge their gasses into the attic area. This is fairly evident from the gas odors… and confirmed when we can actually see it.
Insulation, Vapor Barrier and Ventilation Concerns:
Insulation – The insulation is meant to keep the living space below the attic warm. The most common issues I find are too little, inconsistent, compressed or missing insulation. 
The main concern is heat loss, which leads to higher energy costs. So, it makes a lot of sense to ensure that the attic space has adequate and consistent insulation. When the insulation has been compressed or wet from leaks or condensation it loses its R-value (The greater the R-vale, the better insulation can resist heat loss)
The main concern is heat loss, which leads to higher energy costs. So, it makes a lot of sense to ensure that the attic space has adequate and consistent insulation. When the insulation has been compressed or wet from leaks or condensation it loses its R-value (The greater the R-vale, the better insulation can resist heat loss)
Sometimes however, adding too much insulation in the wrong areas of the attic can be problematic as well, because it will make the attic colder, but not necessarily limit the moist air that leaks into the attic (this is what vapor barrier is for). As a result, condensation builds up on the wood members because the warm moist air mixes with the cool attic air before it can be vented out. If left unchecked for long enough, rot damage will happen.
In older homes, there is the possibility of finding dangerous insulation, such as vermiculite containing asbestos. When disturbed, the tiny particles of asbestos can get lodged into the lungs leading to cancer, years down the road. I recommend that the vermiculite be tested. If the test reveals that there is a dangerous percentage of asbestos found, then a Hazardous materials company must be called in to remove it. This can be very disruptive and expensive, depending on the time it takes and the overall amount to be removed.
Vapor Barrier – When installed correctly, the vapor barrier is essentially what stops the warm, moist air from the living space from entering the attic from below. In cooler climates the vapor barrier must be placed on the warm side (below the attic insulation). The main problems we find includes incomplete, incorrect placement and vapor barrier that is missing altogether. Really, any opening from the living space below can lead to moisture related problems, depending on the temperature and ventilation in the attic. Some common leakage points include, plumbing attacks, pot lights, vents, ducts and around chimneys. Subsequently, a properly weather-stripped and insulated attic hatch with vapor barrier is one of the best ways to reduce the heat and airflow into the attic.
Ventilation – Proper ventilation is the last piece of the puzzle. The different types of attic vents include ridge, (at the very top, along the length of the roof peak) roof, soffit, and gable vents. Poor ventilation usually happens as a result of improper installation. One condition I frequently discover is when soffit vents have been blocked by insulation. Other times there are not enough roof vents installed. Ideally, about 50% of the ventilation should be located in the soffit areas.
Again, if the attic ventilation has been obstructed or there is or inadequate ventilation then condensation will take place, leading to mildew, mold and rot damage.
I have also seen other problems in the attic such as broken bathroom vents, laundry exhaust vents discharging into the soffit areas, torn vapor barriers, bee hives and other pests, just to name a few.
