VERTEBRATE PESTS:Spending Time Up On The Roof

Around buildings, the ground level is a critical zone for inspections and pest management procedures to keep rodents, insects and other arthropods in check. Pests enter buildings through various foundation wall breaks, beneath doors and around improperly sealed ground-level utility lines.

Too many times, however, the easily accessed and inspected ground-level areas receive the majority of an inspection’s attention, while the more difficult to reach and less visible overhead aerial areas and roof tops are not checked regularly enough.

Two months ago, this column discussed the importance of inspecting and servicing overhead areas (e.g., suspended ceilings) inside buildings. This month, we continue the discussion of inspecting overhead areas but focus on the exterior, namely roof areas for both residential and industrial clients.

RESIDENTIAL ROOF INSPECTIONS. For routine aerial areas for residential inspections, it isn’t necessary to get out the ladder and climb to the roof to look around each service visit. But because the typical residential roof is vulnerable to a range of pests it should be inspected at least to a cursory level each time the residence is serviced. The following pests are but a few of the vertebrate and insect pests that commonly enter houses through the roof or harbor within soffits and attics of houses: bats, tree squirrels, raccoons, opossums, mice, roof rats, pack rats, birds, ants, bees, wasps, spiders and several other insect pests.

Obviously, for those pest professionals who work with bird and roof rats on a regular basis, inspecting and working on roof areas is an essential part of their work. This is also true for wildlife control operators that manage tree squirrels, raccoons and bats.

Areas and items to inspect during a residential roof inspection include checking for warping or damaged fascia boards and soffits, uncapped chimneys, warped flashing around stacks and chimneys, clogged gutters and broken or rotted out louvers and vent screens.

Keep in mind that informing a residential client of a structural issue prior to it becoming a serious expense is perhaps the most important service you could provide. Thus, all faults and damaged areas should always be brought to the client’s attention. Consider the value of being informed of a structural problem caught early as compared to a “preventive spray application” to keep exterior perimeter pests in check. Which of these two services seems more valuable to you if it were your house?

COMMERCIAL ROOF INSPECTIONS. With industrial commercial accounts, roof inspections are especially important. This is true for food plants, warehouses, hospitals, hotel complexes, schools and pharmaceutical plants. All of these facilities (and many others) are vulnerable to roof area pest problems because many of them vent large amounts of food odors or warm temperatures out through the roof. These resources are of obvious value to birds, mammals and a host of flying insects. Commercial roofs often process large amounts of air for cooling, resulting in condensate puddles and streams. This water is obviously of critical value to birds, ants, bees and wasps and other pests.

The following areas of commercial roof tops should be inspected on a periodical basis (e.g., quarterly) by a servicing pest management professional.
1. Drains and gutters. Accumulating water on the roof attracts a wide range of both vertebrate and insect pests. Oftentimes roof drains are overlooked by the sanitation and maintenance staff of our commercial clients. For example, roof drain covers commonly blow away or are knocked out of position. This results in leaf debris or product fines (those pieces and parts sometimes blown out of roof vents as part of manufacturing) clogging the drain and causing a wide range of problems for the client. During the warm weather months, significant fly problems can occur in these clogged drains. Or, the backed up water attracts bird and wildlife pests. In the colder parts of the country, the rain downspouts are usually channeled through the inside of the building. In other areas, they are channeled along the outside walls. Outside wall spouts should be rodent-proofed at the top and at the bottom to prevent rodents from accessing the drains and gaining access to the roof.
2. Air exhaust and intake hoods. The screens on the underside of these hoods must always be checked to ensure they are in proper repair and sitting (or secured) properly in place. If not, birds and other animals will enter and become trapped or contaminate the duct system.
3. Roof insulation and covering. Rats, mice and insects commonly harbor beneath various types of roof coverings and within roofing insulation. Vinyl and rubber-style roof coverings must be inspected for rips and tears or rodent gnawing, especially at the bases of parapets and where the covering is covered up by parapet walls. Processing plants that manufacture grain products (using flours, grain fines, sugars, etc.), and that also contain rubber or vinyl roof covers, can be particularly vulnerable to serious rodent infestations, which can be found directly beneath the roof covering.
4. Accumulating food spills. Rooftops of commercial food manufacturing plants should always be checked for overlooked or forgotten food spills and blowouts. Obviously, when spills are allowed to remain, they will quickly attract birds, rodents and insects.

CONCLUSION. In summary, roof areas for both residences and commercial accounts are just as important as ground level areas (and perhaps more so) for routine inspections. In fact, it is fair to say that our clients should expect their pest professional to keep a trained eye on roof areas while performing routine service work. The results, even when everything is OK, should always be delivered to the homeowner or commercial client. This one service activity alone can demonstrate to your clients the value maintaining the services of a pest management professional.

The author is president of RMC Pest Management Consulting and can be reached at rcorrigan@pctonline.com or 765/939-2829.