February, 2003
Inspection News and Views from the American Society of Home Inspectors

Animal Damage Inspections


The national team of wildlife control experts at Critter Control has seen it all. The experts have removed squirrels, raccoons, and bats – even deer – from inside buildings. They’ve found holes in roofs, damaged electrical wires, foundation problems and plugged chimneys. They’ve also found dead animals in walls, heat ducts and toilets, and skunks, opossums and woodchucks living under decks and concrete slabs.

CCNest-in-Vent.gifHome inspectors are also aware that birds and animals frequently move into homes and buildings uninvited. They find the damage done by these interlopers, and sometimes they encounter the perpetrators themselves. But as ASHI Member James Hanratty advised, unless a home inspector is absolutely certain he knows what kind of animal is present or has caused the damage, he should allow the experts in this field to identify and deal with the pest problem. (Photo: Sparrow nest located in an attic lower vent.)

Hanratty said home inspectors may choose to note the likely suspects when they report the damage and recommend contacting a control professional; but there’s no reason to go further because control experts should conduct their own inspection before recommending action.

CCAEW-Roof-Vent.gifAnd, according to Kevin Clark, Critter Control founder and CEO, this isn’t your typical building inspection. In fact, except for work incidental to their main mission, wildlife control experts aren’t building inspectors at all. Clark has been licensed as a pest control operator, residential builder (with HVAC) and real estate agent for more then 20 years. Based on lessons he and his team have learned over the years, and the techniques they’ve developed to locate animal-caused building problems, he believes the inspection should begin with an interview and proceed according to a set format. (Photo: Attic vent destroyed by a raccoon – Notice the hardware cloth installed under vent, which prevented easy access by the raccoon. This is a simple step that can prevent animal intrusion.  Better yet, simply install new stainless steel roof vent guards.)

Inspecting for animal damage

The typical animal damage inspection begins with an interview of the building occupants.

What have they seen, heard and even smelled?

Where, when and how long has it been going on?

AEW-Roof.gifClient responses and an intimate knowledge of wildlife biology, animal behavior and life histories are necessary to identify the offending species. If the animal can be correctly identified and its behaviors are known, the likely type and location of the animal damage can be quickly determined. For example, daytime activity in a bathroom fan duct would suggest birds, and a very different type of damage and resolution than would the nocturnal noises that a raccoon with a litter of young might cause in an attic. The sounds and smells of a colony of bats in an exterior wall would be damage of a different sort still. (Photo: Animal entry point located above fascia board
(gutter line) - most likely caused by a raccoon who found soft (rotted) roofing material.)

Report form the key

AEW-Utility-Line.gifMuch like tools used by traditional building inspectors, the key to the Critter Control inspection is a copyrighted Animal Entry Worksheet & Inspection Form. This inspection form organizes the inspection and allows for a logical discussion with the client. Although the inspection form format may be familiar to building inspectors, many of the skills and thought processes involved in finding and identifying animal specific damage are not. Is that dropping from a bat or a mouse?  To a person who knows the habits of each animal, the answer suggests what type of damage to look for and where to look for it. For instance, mouse droppings are usually dull, and fairly firm or even hard; while bat droppings may be shiny with insect parts and crumple readily. (Photo: Common entry point for mice, rats, ground squirrels, birds and other small animals. Better attention should be paid to utility line entry points.)

Rac-in-Workroom.gifThe first stops on this type of inspection are inside the attic and the crawl space. Clark recommends starting inside the building to avoid tracking dirt and debris in from the outside. It is rare to actually see an animal in an attic, but caution and attention are appropriate. A cornered wild animal in the confines of a cramped attic or crawl space can be hazardous to one’s health. It is more likely to find an animal trail in the insulation, a pile of bird nest debris under a roof vent, droppings – or nothing at all. Anyone who inspects an attic should always watch for exposed electrical wiring, because rodents, such as squirrels, mice and rats, chew on wires to keep their constantly growing teeth short and sharp. Sometimes luck prevails and enough light enters from the outside so that exposed wiring, other damage or signs of animal presence are plainly visible. But more often visibility is poor, making it difficult to find and identify damage. (Photo: Raccoon in workroom.)

Sq-in-Fireplace.gifAfter inspecting the attic, the control expert conducts a gross exterior inspection, beginning with a ground level walk-around to find obvious animal damage, such as a soffit vent torn open, apiece of siding peeled back, construction gaps or damaged shingles. A good pair of binoculars comes in handy for inaccessible areas, as a search continues for animal tracks and claw marks on the building indicating an animal is coming and going. Find these and it’s likely there is an entry hole somewhere on the building. If a potential entry is found, control experts look for the telltale gray-to-black “slick” left by animal body oils on structural surfaces as an animal repeatedly enters and exists a building. A noticeable slick suggests the problem has been long-term and the damage might be severe. Overhanging tree branches, downspouts, corner trim and trellises are typical places to look for the signs animals leave as they come and go from a structure. Utility lines can serve as critter highways to the roof. Lower on the building – decks, porches, foundations and concrete slabs – can be damaged or undermined by burrowing animals. (Photo: Squirrel in fireplace.)

House-Vent-Repair.gifOnce the general exterior condition of the building has been inspected and recorded, it’s time to get the ladders off of the truck. Gutter lines and the interface between fascia boards and roof sheathing are prime locations for animal entry and damage. In many cases gaps left at the time of construction provide a toehold (or tooth hold) for animals to find and enlarge. The proximity of these gutter line entries to rain water increases the chance of wood rot and water damage. Conversely, failure to keep gutters clear of debris can cause softening of wood surfaces leading to or exacerbating animal damage. Home inspectors as well as control experts should consider animal involvement when they find damage at the inside corners of the gutter line under roof valleys and the outside corners where the gutter and soffit end. More evidence: have the louver vents been damaged and is the original louver vent insect screen ripped? Insulation, hair, tracks and droppings found in the gutters might help identify the offending bird or animal and pinpoint likely damage locations. (Photo: Common entry point for mice, rats, ground squirrels, birds and other small animals. Better attention should be paid to utility line entry points.)

Roof valleys are a great place to find and identify droppings that have collected after rainfall. Roof vents and attic fans can be damaged or even torn off by determined wild bird and animal invaders. Dormers are carefully checked; the angles and overhangs are prime locations for animal damage. Chew marks and tooth patterns can often be found near animal damage and may be a key to identifying the species involved. Chimneys and vents (masonry, wood burning, gas appliance, sewer stacks) are always considered as potential animal damage or entry locations. Wildlife knowledge and proper identification can translate into efficiency for both home inspectors and control experts when it comes to finding animal damage on buildings.

Animals must go

Finding animal damage is only half the battle. All animals must be gone before repairs are initiated. Experience shows that clients take a dim view of the annoyance and additional damage caused by animals sealed in due to premature repairs. Even worse is the client who must deal with the odors and related insect pests resulting from birds or animals that die from being trapped in a structure by repairs.

Varied and stringent requirements

In nearly every state, the trapping and removal of pest wildlife requires special permits or licenses. The laws and regulations can be complex and some states require specific liability insurance. While home inspectors who learn to find, identify, and report animal related damage provide their clients with valuable information, Hanratty said their service usually ends with a recommendation to the client to contact a licensed animal removal or pest control company.

According to Clark, “People appreciate the application of wildlife knowledge to protect their home and loved ones. For many of our customers, it’s like we are ‘The Crocodile Hunter’ and ‘Jungle Jack Hanna’ all wrapped into one … live and in person.”  

For home inspectors and homeowners, he says answers to wildlife pest questions can be a simple phone call away.