Common Home Wildlife Damage

Wildlife infestations always leave some type of damage to the home.   By simply entering a home, wildlife will often cause damage.   Vinyl panels can be torn loose when squirrels climb into soffits, woodwork is chewed open, siding is torn loose, etc., and this does not even include inner home damage that is done once wildlife gets in.

Wildlife damage can range in severity.  While no one wants wildlife chewing up their woodwork, a little bit of woodwork damage doesn’t even hold a candle to having the entire house burn down because of damaged wiring.   Damage is wide ranging, but a few issues seem to repeat themselves The more common problems that I encounter are:

1)      Squirrels chew at woodwork along the gutter to enlarge openings so that they can crawl into attics. 

2)      Vinyl soffit panels are torn loose or chewed out opening entry into soffits/attics from rooftops.  

3)      Flexible ductwork is torn open/shredded and feces/urine deposited inside.

4)      Gable vent screenings are torn open or chewed through.

5)      Foundation vents are torn/pushed open.

6)      Digging occurs under homes, decks, outbuildings.

7)      Wiring damage occurs due to chewing.

8)      Deposits of feces and urine from wildlife in homes.

Woodwork Damage

Have no doubt, rodents can damage woodwork.   Squirrels will gladly chew trim work.   They do this to help maintain their teeth which are eternally growing.  If they don’t chew, the teeth will grow too long and keep them from eating.  Chewing is critical to their survival.   I have also read that rodents actually enjoy chewing.   They grind their teeth together when they are anxious or happy.    You don’t want some type of rodent in your home satisfying his or her natural urges on you home. 

Secondly, wildlife chews to improve access to parts of your home.  If a passage is a little too close for comfort, they can easily open it up a little “Chew Chew Chew Gnaw Gnaw”!!!  But, a squirrel is never satisfied and there is often more than one squirrel.  Over the years, damage can accumulate.   Wildlife-damaged wood on the exterior can be replaced much easier than support timbers that are on the inside of the attic.  I am sure that it would take a lot of squirrel chewing to undermine the structural integrity of a house, but it makes me nervous anyway.    Who wants to be making monthly payments on a home just to let the squirrels chew it up?    The best thing you can do is call a wildlife control professional. 

Wiring Damage

According to statistics that I found online, in the last ten years 37,000 people died in house fires and 8% of those fires were started by rodents chewing wiring.  Theoretically any animal with teeth can damage wiring.  I have seen wiring damaged by raccoons.  Young raccoons will chew on things when they are cutting teeth.  This is just like a puppy chewing up your slippers when they are cutting teeth.  But overall, I believe that rodents are the primary cause of this problem.  I have found wiring damage while working on mouse, gray squirrel, flying squirrel, raccoon, and snake projects.   The snakes do not damage wiring, but they will come inside following mice that do damage wiring.   

When I see wiring damage it is usually in the attic or crawlspace.   But wildlife species regularly enter walls and other small spaces where inspection is impossible.   Damage here may be hard to detect and harder to repair.   A shorted wire can cause a house fire.

I always tell customers that damage is proportional to the number of wildlife pests and the length of time that they have had access to the home.  A single rat is unlikely to chew the insulation off your wiring in its first afternoon inside your walls.   However, homeowners can go for years, in some cases, even decades before they realize that there is a problem.  This is a good reason to have your home inspected for wildlife damage.

Damage to AC System

Flexible Ductwork – The Softest Part of the System

Soft flexible ductwork is a prime target for wildlife to damage.  I have entered attics and seen flexible ductwork left in a “spaghetti tangle” and the homeowners paying high heat and cooling bills.  They did not connect the noises that they were hearing in the attic with their rising energy cost.  Some families have this going on for years before they discover the problem.

Rats love to chew through the walls of flexible ductwork so that they can run through.   Once they cut through one of the ducts, they have access through the entire system. Feces and urine will begin to accumulate inside the ducts and the homeowner may start to smell an odor.  This happened to one of our clients between Bristol and Abingdon.   The odor was the first sign she had of rats in the house. I trapped about 15 rats in her crawlspace before we finished the project. Obviously her problem was much bigger that what she originally knew.

Damage on the Supply vs Return Side of the System

Ductwork has two parts or “sides”.  The intake and discharge sides otherwise known in the industry as the return and supply side.   The return side sucks air from the house through a filter and brings it to the unit to be heated or cooled.  The supply side blows air through the evaporating coils to heat it or cool it and sends it back to the rooms.  Where the animal decides to chew through the ductwork is important. 

Damage to the Supply Side

If it chews through the supply side, it has access not only to the ductwork, but it also has a readymade highway system that will lead it to every room in the house that is supplied with warm or cold air by the AC system.   Floor registers are usually just dropped into place in the floor.   I don’t see too many that are anchored into place.   This means that larger animals (bigger than a mouse but small enough to fit in the duct) can walk through the ductwork and push the register up with their heads and come on out into the room.  I have had rats do this as well as a litter of half-grown raccoons.  I had to fish one of the raccoons out from under a sofa.  It was quite a spectacle.   Another customer woke up in the middle of the night to see a large rat standing on its hind legs in the doorway to their bedroom.

Insulation mysteriously popping up in floor registers is a good sign that this has happened.   When the animal tears through the walls of the system; a little bit of the insulation gets pushed into the interior of the pipe.  The insulation gets swept along with the air and is caught in the register.   If you have seen this, you should call us immediately to get the animal out before the damage gets really bad. 

Damage to the Return Side of the System

If the animal comes through walls of the duct on the return side it will reach the intake side of the unit.  This is no less troubling for homeowners.  Filters can be damaged and filth and insulation will plug up the machine.   Machine efficiency can fall to nothing.   The machine will continue to run, but it will get harder and harder for it to heat or cool the house.  Air flow through the system will drop dramatically.  You may not get an early warning that this has happened like you would with damage on the supply side of the machine. In this case, insulation will be trapped in the unit itself and not blown to registers. The first sign that you will get is that the system slowly stops working. It is also possible, that both sides of the unit could be damaged at about the same time.  There is nothing to say which side the critter is likely to attack first.

What is Left behind in Your Unit

I met an AC technician on a rat job who was working on replacing the Air Conditioner system.  It had been invaded by rats and was a mess.   The insides of the ductwork were filthy.   The technician said that all systems have some dirt in the ducts, but that having animals moving through the system makes it worse.  They leave a lot of fur, dirt from their feet, urine, feces, etc. inside.   Systems that have been torn into are much dirtier than a closed, properly working system.   He also mentioned that animals also occasionally end up on the heating coils.   The coils are on the return side of the unit and animals that wind up there get cooked.  How terrible!   That funny “hot smell” coming from your unit may be frying rodent.

 Wildlife Inside the AC Unit Hardware

You would think that that big tough metal box that protects the innards of you HVAC system would do an awesome job of protecting it - not necessarily so.  Sometimes animals even get inside the AC unit itself.   I once met a lady who came home one day to find a snake skin hanging from the air duct right over her couch.  Needless to say, she was a little stressed about the possibility of snakes in her house, not to mention the possibility of one plopping on her while she was watching TV.   Mice had found a couple of small holes in the metal cabinet that covered the inner parts of her system.  A snake (or snakes) had followed the scent trail inside.  In short, she had a small ecosystem in her ductwork.  

In situations like this, knowing where to look to find the problem takes some skill.   Few people would think to check the right locations and would leave holes somewhere.   The problems lie not only in the ac unit itself, but also on the exterior of the house.

This is what generally happens in this situation.   First, let’s talk about what has happened to the AC system itself.  Some species of wildlife do not have the capability to chew or rip into a duct.   If flexible ductwork is breached, wildlife can travel through this ductwork to reach the interior of the AC unit.   Construction of the unit determines a lot about whether or not it is vulnerable to infestation by wildlife.   I have seen holes in the outer cabinet of the unit where tubing passed that was only plugged by foam or plastic.  Once the foam was chewed out, it was an easy thing for wildlife to enter the unit and create havoc.  

If wildlife cut through the walls of the ductwork and makes it into the system, they can easily reach the unit.  What part of the unit they reach, intake or discharge, determines what the animal may encounter.  Animals may encounter wiring to chew on, circuit boards to urinate on, or filters to chew through.   Air conditioners were not made to house wildlife and they don’t generally fare very well when this happens.  Things can get expensive quickly.  Even a few mice that chew into a unit can cost a couple thousand dollars.  If the animal is inside the unit itself can it damage the unit, most certainly.  

 Have You Found Insulation in Floor in Your Floor Register?

Recently, I had a customer tell me that they had seen insulation show up in the floor register.  They thought nothing of it and went on about their business.   Later they heard noises in the middle of the night.   They opened the return on the AC system to see an opossum looking back at them.    The opossum had torn open some flexible ductwork to enter the system.  When it did, it released a little bit of insulation into the system and it blew along with the draft generated by the blowers.   It bounced along inside the duct until it was caught in the floor register.    I have seen the same thing happen to clients who were trapping rats.   If you see insulation mysteriously appear in your floor register; it is a good sign that your ductwork has been breached. 

Don’t be too Quick to Repair Ductwork

At about 3:00 am last fall I got a call from a lady who had an opossum staring back at her from behind her AC filter.   I came right over and learned that she had already had a local air conditioning company replace parts of her ductwork a few months before.   I felt sorry for the lady.   She was right back where she was and with less money on hand to deal with the problem.    The HVAC guys knew what had damaged the system, but they tried to take care of the wildlife control work themselves and did a poor job.  They didn’t do the lady any favors.  Before you fix the system, you need to be absolutely sure that all the entrances are sealed and hardened up.  It might also pay to have a couple of inspections done at key times after the sealing is done just to make sure that things are good.  Wildlife is working 24/7 to find a good place to nest or keep warm. 

What to Do First – Getting Rid of the “House Critter”

You should realize that a huge portion of my business involves removing denning females and litters.  You may remove this year’s problem, but denning season will roll around again next year and you will be right back where you are now.   If momma was happy with her accommodations she will be back.  Lots of customers tell me that they had been having wildlife infestation problems for years before.  I believe in what I call the “old home place” effect.  I suspect that juveniles that grew up in a certain attic might be likely to return to their “old home place”.  At any rate, just remember, that that critter entrance has an invisible “vacancy” sign flashing outside of it that the entire animal kingdom is aware of.

Should I call a Professional Wildlife Trapper/Controller

Once you discover that you have wildlife damage to your home, you need to make sure that those critters are evicted!  Whatever the species is, they need to be evicted.   Keeping the critters on the outside prevents problems and lets you sleep at night.   Sealing up the entrance means screening out the problem animal and a permanent solution.  But, you can’t just shove something in the hole and walk away or just try to trap the animal and haul it off.  This will leave you with problems later.   

At this point most people need a wildlife control specialist.  The trick is to remove all the animals from the home and seal the entrances permanently.  This is not a simple process.  How do you know if there is a litter in the home, and if there is, how do you get them out?  What do you do with the animal once you have it trapped?  What legal issues are involved?  I show up at homes lots of times to find some type of badly done wildlife screening, burrow plugging, or other failed measures that didn’t effectively keep the animals out.  Lots of times the damage is severe.   It would have been a lot cheaper to have called a professional in the first place.  Now the customer has to spend money on securing the home and on repair/clean up as well.