SOMETHING’S IN THE ATTIC

Getting a call from a customer who’s hearing noises in his or her attic or walls can sometimes be a difficult and frustrating problem to solve. Gaining access into these areas and figuring out what needs to be done in order to solve the problem seem to be two of the most common areas of concern. There are a wide variety of animals that can, and do, find their way into attic spaces and walls of our customers’ homes and businesses. In this article we’ll take a look at how to develop a plan to effectively deal with these calls.

UNDERSTANDING CONSTRUCTION. In order to successfully solve pest concerns in walls and attic spaces and prevent their recurrence you must have a good working knowledge of home and attic construction. You also must be familiar with the types of potential animals that may invade structures in your part of the country, as well as their biology and habits.

One day I received a call from a business that had an odor problem at its offices. On site I found that there was a flat roof with a drop ceiling in place. After gathering information from the office staff and some extensive inspection work on a stepladder I was able to find a dead mouse in the insulation over the ceiling space. It seems that the pest control company that had been providing services had placed rodent bait inside the office (at ground level) and the mouse had been traveling up through the wall and nesting in the overhead insulation where it had died.

The owner said that the office occasionally had mice and asked what they could do to prevent this problem from recurring in the future. After inspecting the building I sold him an exclusion service and quarterly pest control service program. The mice appeared to have had access into the building through weep hole openings that were at ground level, several building expansion joints and one utility line entry point. (The weep holes were “sealed” with Stuff-It brand material so that the weep holes would still provide needed ventilation to the wall voids.) One thing to always keep in mind is that just because there’s a “critter” in a wall, ceiling or attic doesn’t always mean that it gained access from immediately outside the attic space.

ATTIC LEVEL POINTS OF ENTRY. One of the most common points of animal entry into an attic space is through the attic louvers. Oftentimes these are poorly screened or the screening has been cut or damaged to the point where access is possible. Bat urine will corrode screen wiring and over time cause it to virtually fall apart. House sparrows will build nests between the louvers and screens and eventually push the wiring loose. Tree and flying squirrels will often cut holes through screen wire. If a raccoon wants in an attic bad enough it will sometimes simply rip through the louvers and screening to gain access. Some of the newer non-metal screening seems to weaken over time when exposed to heat and sunlight and will then easily tear or break.

The enclosed area of the roof that extends beyond the side of a building is referred to as the “soffit.” This roofline extends down to a fascia board where there may (or may not) be gutters attached. The soffit is enclosed or “boxed in” with wooden or vinyl sheeting underneath with the ends normally closed off with “end boards.” It is fairly common to find fascia or end boards that have come loose through weathering or decay and these openings can serve as points of entry for animals. When two rooflines run together there is often a gap or crack that often provides an access area into an attic space.

When roof sheeting is installed during the construction of a new home, it is fairly common for there to be a gap where the sheeting meets the fascia boards. In many cases the shingles will cover this gap or metal “drip flashing” will be installed to cover this gap. When there is an unsealed gap present between the roof sheeting and the fascia boards then animals such as mice, rats and squirrels will often gain entry into the attic at these locations. It is usually necessary to use a ladder to gain access to inspect for gaps, holes and openings around roofline junctions and between the roof sheeting and fascia boards.

Exhaust fans come in many shapes and sizes. Some are mounted on the ends of the attic space and others, like “mushroom”-type roof vents, penetrate up through the roofing. Raccoons and tree squirrels will commonly use these vents for points of entry. Bathroom exhaust fans are often ducted up into the attic and out through the side of homes. These vents are a favorite nesting site for starlings. Once starlings begin nesting they will commonly peck through the thin exhaust vent “flexi-duct” and actually end up nesting in the attic space.

In many newer homes the chimney may be simply a hollow void space covering a “flue pipe” running up from a prefabricated fireplace. Many animals have been known to gain access into these voids. Once an animal is in the chimney void it can often obtain direct access into the attic space or walls of a home. Masonry chimneys will at times settle and pull away from the building’s sidewall. If this happens then a crack will appear that can also provide direct access for pests into voids or attic spaces.

Many commercial buildings with flat roofs have a raised “parapet wall” around the roof edge. These walls are often hollow and have some type of covering or flashing present. Loose flashing around the edge of parapet walls or gaps around guttering penetrating through the wall often provide access for bats and other animals into wall voids or attic spaces of these buildings.

Most buildings have vent pipes for the plumbing vented through the roof. Occasionally squirrels or rodents will cut holes around these pipes to gain access into the attic.

SAFETY: NO. 1 PRIORITY. Any time you are going to go in an attic space or on a roof, safety should be your No. 1 priority. Recently we received a call from a local property management company for removal of a black snake from an attic. The home was an older two-story colonial with an open interior entry that was about 20 feet to the ceiling. When our technician arrived he saw a large gaping hole in the ceiling where the electrician, who had been working in the attic, had fallen through the ceiling in an attempt to get away from the snake. The electrician had been taken by ambulance to the hospital and surprisingly was not critically injured.

When you start to go up into an attic with pull-down stairs you first need to check the integrity of the attic stairs. It is common to find screws loose and the ladder in poor condition. It is helpful to have an adjustable wrench in your truck just in case you need to do some screw tightening prior to climbing up.

If you are using a ladder to gain access into an attic “cubby hole” remember the warning on stepladders that says, “Do not use the top of this ladder as a step.” I prefer to use an 8-foot stepladder or a collapsible ladder that can extend into the attic space for easier entry.

Once in the attic I try to “take in” a general over view from the top of the steps, my ladder or the attic entrance. If an attic is unfloored and you need to enter into the space I strongly urge you to have several 1 by 12 boards that you can use for temporarily flooring. If there is flooring present take a close look at how it is installed and the strength. It seems that homeowners will use just about anything that will fit up through the attic entrance for flooring or “storage space.” Thin plyboard and particleboard that doesn’t hold up well in high heat seem to be common in our part of the country.

Of course you need a good light to perform a proper inspection. A quality headlamp is useful and allows you to have free use of both of your hands.

Where blown insulation is present a dust mask helps prevent inhalation of disturbed insulation. If you are in an attic where deer mice or an accumulation of droppings are present, you should wear protective clothing as well as a hepatic filtered respirator with eye protection.

Our bodies don’t work as well in 120+ degrees and you should schedule your attic inspections (if possible) for early mornings. Drink plenty of fluids and remember that when you’re hot and tired the potential for an accident increases.

WHAT ARE WE INSPECTING FOR? When dealing with animals in attics or walls it is important to interview the folks who live in the home . The information that they can provide will often make it a lot easier to solve their problem.

Following the initial customer interview, I normally like to start my inspection on the exterior. This will help you identify potential points of pest entry, conditions that may contribute to the presence of certain pests and the type of construction features that are present. In the case of flying squirrels a large tree immediately adjacent to one side of the home may serve as a “glide tree” for all flying squirrels leaving that structure. A single electrical line with no tree limbs present may serve as a direct point of access onto the roof for a tree squirrel. Ivy growing on the foundation could be serving as a highway for rodent activity or even snake access into the attic space.

Your inspection should always take place with a “3-D” perspective. That is, look at the area surrounding the structure, the ground area immediately around the structure, the sides of the structure and, whenever necessary, the roof. You also need to be prepared to perform a complete inspection with the equipment that you’ll need on your vehicle. You need to be open-minded about what you’re looking for and what type of animals might be present.

Depending on the information I have I will normally inspect the interior ground level and basement level of the structure next. Again, keep in mind that the “critters” had to gain access into the structure and must also be obtaining regular access to food and moisture if they have been in the structure for any length of time.

After completing the exterior and interior inspection then I turn my attention to the attic space. One thing to remember is that in this area there should be some type of evidence of occupancy or movement in the attic space left behind by the animal in question. The first place I always look is at the upper side of the step or cubbyhole cover. Often animals such as mice, rats and squirrels will sit on these “covers” if insulation is not present and leave droppings.

The insulation in an attic space tells a story like a “written record” of what has been in the attic. Trails and holes on and in the insulation made by animals in years past will often be present. You must look closely for this evidence to determine what is old vs. what is currently active. Droppings, trails, scuff marks, chewings, scratch marks, nesting material, evidence of feeding and tracks in dust can all aid you in determining the type and number of animals that may be present. During your inspection of the attic space it is also important to make sure that there are no food sources present. I have found everything from grass seed to old hamster food stored in attic spaces. Mice, rats and some squirrel species will also cache food such as nuts or pet food in walls or attic spaces. Even though these animals have food available to them on the interior of the attic space they will still routinely go out and forage for food. One exception to this statement is when dealing with rodents that may have gained entry into the structure through a broken sewer line, missing cleanout plug or loose section of vent exhaust pipe.

When access to the attic space is not available then it is important to find where the animal is traveling and exiting the space. In these cases this is where your trapping or removal efforts will need to be concentrated.

In most situations I do not recommend sealing the entry points of a structure until all offending animals have been removed. There are few things worse than having a customer dealing with a dead animal odor situation that you contributed to and are unable to locate. In certain cases, such as bat exclusion or a “wide open” structure, it is necessary to seal most openings to create a manageable number of sites where the animal(s) present can be excluded or captured.

CONCLUSION. Keep in mind that a call for “something in the attic” may involve control efforts in the attic, on the roof, in a crawl space or at ground level on the outside. I once had a call in a cluster home where the property owner had seen a rat run behind an organ. Upon removal of the back off of the organ we found that the rat had made a huge nest inside of the organ but was not present. We also found that it was going under a kitchen cabinet. Several days later I caught a single rat in a snap trap outside the carport utility room by an opening where the air-handling unit’s utility lines went through the wall. In this case the rat was going under the cabinets and up into the wall. Its only access to the carport utility room was through the attic space. From there it was going back down the interior of the utility room wall to get into the exterior through the hole by the utility lines. We sealed the opening around the utility lines and the homeowners never had a rat recurrence.

With a little effort and serious “detective work” you should be able to determine what that “something’s in the attic” is. By solving these problems you not only provide a valuable service for your customers but also generate additional income for your company.

The author is owner of McNeely Pest Control, Winston-Salem, N.C. He can be reached at smcneely@pctonline.com.