Appraising, Helpful for FSBO, Helpful Info For Agents, Helpful to Home Owners, Home Repairs

Infestations That Nibble Away Home Value

Sharing is caring!

When I was a kid, on Saturday afternoons I loved watching old sci-fi movies. One of my favorites were movies about bugs and other small creatures that ended up in a radioactive substance, causing them to grow into giant monsters.  Here is an example.

I was intrigued by these kinds of movies because, in my mind, there was a slight possibility that if small insects were exposed to radioactive material, they might really be able to grow into monsters. Of course, this is not possible. While small insects are not likely to ever grow into monsters, they can create monstrous problems to a home.

That’s why in appraisal reports, the appraiser will disclose any evidence of infestation. In fact, in Fannie Mae forms, there is a box to check, if evidence of an infestation is observed.

See Evidence of Infestation Box

The box is easy to miss. But it is an important box to be aware of.  Just to be clear, if the box is checked, this does not mean that there is an infestation.  It means that there is evidence of it, and a qualified professional should investigate the matter to see whether there is an infestation. Appraisers are not experts in the many kinds of possible infestation that might exist. We are only looking for indications of a possible problem.

What kinds of infestation is this little box referring to? Any kind of infestation that would have a negative impact on the market value or marketability of a home. That would include deadly animals, vermin and wood destroying insects.

What are some types of infestation that can have impact the market value and marketability of a home? Let’s talk about several of them.


Termites are small and hard to detect. The good news is, by some estimates, it would take a single termite 3,144 years to eat all of the wood in a thousand square foot home. The bad news is that termites live in colonies of up to 15,000 termites. How much wood can a colony of termites eat? According to Terminix, the largest colonies can eat about a pound of wood a day! According to Colonial Pest Control, a colony of 60,000 can eat about one fifth of an ounce of wood per day. That translates into one foot of a pine 2 x 4 in about six months.

Unfortunately, because they are small and silent, they’re difficult to detected until major damage is already done. The cost to repair termite damage is quite high, as you can imagine. Damage means a loss of value in a home.

The best way to help minimize termite infestation is to make sure there is no exterior wood on your home that is touching dirt. This is often how these little critters get into a home.

If the appraiser notes evidence of wood destroying insects, they would note this on the report and call for a qualified professional to inspect the home to see if there really is an infestation and, if so, the extent of it along with a remedy.

By the way, how can you tell if you have termite damage vs. rotten wood?  Check out this little video.


If you’re like me, the fear of bees and wasps in a home is more about getting stung than in damage to the home. However, they can damage a home. Carpenter bees and wood wasps can bore through wood, causing damage to a structure.  They don’t eat wood, like termites. However, they bore holes to make their nests. I see this a lot in homes with wood panel exteriors or wood siding. I have also seen extensive damage to untreated logs on log homes.

Carpenter bee holes are approx. 1/2 inch in diameter. However, the tunnels they create can be as large as 8 inches in diameter. The female carpenter bee prefers to reuse holes already burrowed through, because it’s easier. However, as they use these same tunnels year after year, the tunnels can get larger, which can cause structural damage. To give you an ideal of the damage that carpenter bees can create, check out this video.

Wasps can also cause damage to a home. Left unchecked, their nests can become quite large, extending into walls, which can damage a home. Their nests are often found on porch ceilings, window and door frames, deck floors, in attics and on overhangs on the exteriors of homes. Most wasps can become aggressive, if agitated, and sting a person. These little critters are welcome in the wild, but not in or on a home.

Check out an infestation of red wasps in this clip.  (I used to love watching this show. It’s a bummer that it is no longer running.)



While carpenter ants can cause major damage to wood, it is interesting that their motives are different than those of termites. Termites eat wood. Carpenter ants use wood to make their nests. This might be why damage from carpenter ants is usually not as extensive as the damage caused by termites.

However, their ability to damage a home should not be under-estimated. According to some insurance companies, carpenter ants can cause as much damage, per year, as a natural disaster. So, they are nothing to mess around with. As is the case with termites, a good way to help minimize infestation is to make sure no wood surfaces on the exterior of your home are touching the ground.

If you see small piles, of what appears to be sawdust, that may be a sign of problems. These small piles are not sawdust. They are called frass. Frass is a composition of soil, dead insects and wood shavings. Water stains may also be a sign of ant damage. How so? When the structural integrity of exterior wood is compromised, it can allow moisture in, which can find its way into the interior of a home.

Here is a video showing what carpenter ant infestation looks like.


ROUS (Rodents of Usual Size)

While the ROUS’s, that is rodents of unusual size, as seen on the Princess Bride, are inconceivable, rodents of a usual size can create some real problems in a home.

Not only do they tunnel through walls and personal property, they also gnaw through wiring, which can cause house fires. One might not be a huge problem. However, they multiply quickly. By some estimates, some small rodents can reproduce up to sixty-three offspring. That makes rabbits look a little slow!

To make the case about rat reproduction, here’s an interesting video showing how two rats become 15,00 in a year!

Okay, we’ve talked about rats. How about bats? Other than being a nuisance, can bats really cause damage to a home?

Bats have one of the fastest fecal accumulation abilities of any mammal? I’m pooped just thinking about it. Bat feces, also known as guano, can contaminate an attic. The odor that is created from bat droppings and urine can permeate a home. Guano carries diseases that can be fatal to those with a weak immunity.

For instance, bat guano often contains a fungus called histoplasma capsulatum. The spores of this fungus are microscopic and can easily become airborne. If inhaled, a person can develop a chronic lung infection, which left untreated, can be fatal. Like other rodents, bats also chew into wood and can damage insulation and wiring.

Check out this video.


I’ve covered a lot of ground in this post. We’ve talked about termites, to bees & wasps and rodents of different sizes. Hopefully the videos I shared are helpful in demonstrating how these little critters can nibble away at the value of a home.

The point to take away from this article is this… If you see even the smallest evidence of an infestation, get it checked out. And if an appraiser sees evidence of an infestation, they will call for it to be checked out. It might keep a small problem from become monstrous!

If you’ve ever seen or experienced a horrible infestation, please share it in the comments below. I’d love to hear about it!

As always, I am grateful to you for reading my articles! I hope you find it interesting.

Have a great day!


Looking for a qualified real estate appraiser in your area? Go to

FindMyAppraiser Logo


Are you a consumer looking for information on real estate? Go to

Consumer Home Value Logo

If you enjoy listening to podcasts, check my new podcast out. I hope you enjoy it! You can find my on Apple Podcast, iHeart Radio, Spotify, Google Play Music, Sound Cloud,, RadioPublic, Deezer, Breaker, Stitcher as well as other feeds.

Home Value Stories Logo

You can also listen right here at Cleveland Appraisal Blog!

Here are some links to other articles and videos I enjoyed recently! I hope you will also…

Housing Is Like Dogs Jumping From Trees – Housing Notes by Jonathan Miller

Crack in The Foundation? – Voice of Appraisal with Phil Crawford (PODCAST)

6 Ways Floor Plan Sketches Can Help Birmingham Rental Companies – Birmingham Appraisal Blog

How do I find a good home appraiser? – Rachel Massey’s article at ConsumerHomeValue

Legacy Appraisal vs Data Science Approach – George Dell’s Analogue Blog

The market is hot (but dull on paper) – Sacramento Appraisal Blog

FIRREA Under Attack – Spectacular Spirals – Lending Up to 2005 Levels – APPRAISAL TODAY

Independent, Objective & Impartial: The Appraiser’s Creed – The APPRAI$AL Cast (PODCAST)

I Couldn’t Think of a Snappy Name for this Podcast – The Appraiser’s Advocate with Time Andersen (PODCAST)


10 thoughts on “Infestations That Nibble Away Home Value”

    1. Thanks Joe! I believe that climate change is having an impact on infestation. In my area, and much of the northeast, our winters are getting warmer, which is leading to more insects in the summer months. It will be interesting to see how this continues to change.

  1. But what if you’re “infested” with era charm or a modern vibe….? Okay, I’m kidding. Nice job Jamie. It’s been a long while since I’ve seen the “infested” box because this check box is not located on the private appraisal form I use.

    1. Haha! Good point! 😃 Truthfully, I have not seen a lot of homes with evidence of infestation either. However, whoever our client may be, if we see signs of an infestation, we do well to mention it in our reports. At least in my opinion. That being said, it’s rare to see.

  2. I have a house in an estate that I am working on as we speak. Wish I could attach some photos to this reply so you could see the carpenter bee holes on the exterior siding and the bat droppings in the interior. The masterpiece was created by the owner’s son. He nailed a big rat trap to the siding by the eaves next to the hole the squirrels are using. It even gets better. There has been no central heat in the house since the famous blizzard of 1978. With assignments like this, I wonder if I made the wrong career choice…

    Keep up the great work on these blogs, Jamie.

    1. Hi Cynthia! Holy moly! That sounds horrible. This is the kind of appraisals that will keep ya up at night. Hang in there! I hope you never have to appraise a home that bad again. Thanks for sharing this. Proof that infestation can impact value!

Leave a Reply