Inspection Unit 3C

Types of Inspections

This section breaks down the inspection process into its component parts. A complete inspection will require all these sections. However, if you only need to do one of them, then the appropriate lesson should provide a good introduction.

On-site Inside of House

Now that the outside is done, proceed to look at the inside. Generally speaking, the most important areas of the house to inspect will be the attic and various crawl spaces. Once done with the attic, you should proceed to investigate the basement. I don’t like crawling around attics. It is messy, dangerous, and uncomfortable. However, since you don’t know in advance if the attic will reveal something, you must inspect it. From the inside, you can better inspect the screening on the vents. Sometimes it looks intact from the outside but the inside reveals that it has been pulled away from the edge or chewed through. Sometimes you may even find bats hanging on the screen.

Turn your flashlight off and look for light entering the attic. If you see areas where the light is entering, make sure its not due to a ridge vent or soffit vents. Modern houses have a lot more vents than older ones. Be sure to note all vents before you enter the attic. Mushroom vents are difficult to inspect because the mesh isn’t in plain view. Use your mirror to inspect the integrity of the mesh.

As you enter the attic, you must always be concerned about safety. Falling through the floor is a real possibility. Make sure you walk on the crossbeams and not on the insulation which fills the space between them. But remember even this safety tip doesn’t guarantee that you won’t fall through. Sometimes the cross beams are too weak to hold you and they can break. If insulation obscures the beams, you can get an idea of where they are by looking at the trusses or by moving the insulation. If it is too dangerous to crawl around the attic then at least try to get a good look at it from the ladder you are standing on. You also want to be wearing, at minimum, a HEPA filter mask. Attics, being confined spaces, can expose you to dusts and fecal materials that you don’t want in your lungs.

Pay careful attention to the insulation. You would be surprised how much it can tell you. I like to look for quarter size holes in it. If I find them, then I know I am dealing with mice. Blown and fiberglass insulation will also reveal trails. Mouse trails can be very faint. The insulation will look like someone rolled a small rubber ball over it.

Mouse trails in insulation. Photo by Stephen M. Vantassel.

Obviously, trails made by squirrels or raccoons will be very pronounced. If you see the paper backing of fiberglass insulation without the fiberglass, then you know a squirrel has been stripping the insulation for a nest. As always, keep an eye out for feces. While mice feces are usually under the insulation, there are exceptions. I would also encourage you, as I did earlier, to wear a high quality filtration mask. I suspect that insulation fibers and your lungs don’t get along well. Sure it’s hot in the summer, but the protection is worth it.

Finally, if possible, I like to stand up in the attic so I can follow the roofline down to the soffit area. It is in these soffit areas that squirrels in my area like to live. Standing is usually the only way to see the soffit area because it lies below the level of the attic floor.

Even if the job seems simple, I would still strongly suggest that you inspect the property carefully. Sometimes the building has had multiple problems that the seller has quickly tried to solve.

Most of my writing thus far has centered on visual clues. I would be remiss if I didn’t advise you about using your sense of smell in your inspections. I don’t want to give you a false impression. Odors will constitute a very small part of your inspection work. However, I want you to be sure to pay attention to your nose. You will find that squirrels and raccoons have a distinctive odor, just like skunks. Pay attention and you will soon be confronted with a time where you can diagnose the problem just by taking a deep breath. I just wish I could put odor samples in this article. Urine smell can come from a variety of sources: raccoons, bats, mice, rats, pets, etc. Identifying which source is the culprit can really only be properly done by a thorough inspection of the property. Look around your building for holes and openings.

The following general information will focus on hole openings various species need. Identification of the problem species is often difficult. Many signs, especially for smaller animals, overlap one another. The difference between a novice and a professional lies in the ability to: a) find the signs and b) piece them together to make a diagnosis. Sometimes a definite determination is not possible; however, you should be able to significantly narrow the possibilities.

  • Mice need ¼-inch size openings and leave rice seed type droppings scattered about. If you touch them (with gloved hands) they will be hard. I also want to warn you about Hantavirus when dealing with mouse droppings.
  • Gray squirrels need a minimum of 1 ½-inch diameter holes but will typically be about 3 inches. You may or may not find droppings. They are notorious for shredding pink insulation down to the paper for their nests.
  • Bats need at least a 3/8-inch gap and their droppings will be concentrated below where they roost. The droppings will crumble like dust when disturbed. Again don’t forget the need for HEPA mask (at minimum) as bat droppings, like bird droppings, can carry the fungus that causes Histoplasmosis.
  • Birds need various size holes (inch diameter would be a minimum) but you will often find the tell-tale white dropping on the building below where they enter. If you can’t find any holes, then you must think internally, i.e. the source of the smell is internal to the house, such as a broken pipe, pet, etc.

Finally, as an inspector, you need to think about the home that is too good. Just as in buying a used car that has a new paint job should make you curious as to what happened to it, so too should the house that has all the preventative steps taken for wildlife. For example, if you come to a home with hardware cloth installed over the attic vents (from the outside), you should ask yourself, “Has this house had problems with squirrels or raccoons?” The general rule of thumb is that homeowners only buy what is needed to solve their problem at the moment. Few of my clients ever accept my advice for installing preventive animal damage measures. Here are some preventive measures that should clue you in to the building’s past struggles with wildlife: Finding mouse poison in crawl spaces. Attic vents screened from the outside with hardware cloth. Dryer vents and other exhaust vents screened. Aluminum flashing (painted or otherwise) installed at the eave level. Usually a squirrel hole was repaired here. Chimney caps suggest previous animal activity in the chimney, although a good builder may be proactive. Wire screening around porches and decks prevent skunk dens.

In conclusion, don’t get overwhelmed with the data presented here. Inspections can be a frustrating exercise. It will help to systematize your inspections so that you can reduce the variables and narrow the possible causes of the problem. Don’t worry if you can’t remember all the things I mention here. I have included a reproducible checklist located at the end of the lesson that you can use on each of your jobs. Sometimes the clues are right on the attic floor, like these bat feces.

©2005 Stephen M. Vantassel

Unit 3D