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AL Greene

Dr. Greene is an entomologist and national IPM coordinator for the GSA’s Public Building Service in Washington, D.C. He can be reached via e-mail at


[Industry Observer] The Green Building Burden

Green Pest Management

Sustainable design is a beautiful concept. Just not for pest control.

October 21, 2014

Even for an ancient, counterculture rebel such as myself, it is not at all pleasurable to take issue with motherhood and apple pie. But after about 15 years of intensive experience with a wide assortment of green buildings, I’m forced to conclude that although they are a wonderful, overwhelmingly positive development for society in general, they are nothing but an aggravation for pest management professionals. Even more dismaying — and I had such high hopes! — they have proved to be no less susceptible to the same basic architectural and operational flaws that plague their less environmentally fashionable cousins. Since there is a growing mythology that these structures are mostly beneficial for our industry, it’s time to temper this illusion with a cold dash of reality.

An Impeccable Notion.

The green (a.k.a. “sustainable,” although it’s not a true synonym) building movement is one of the developed world’s most rapidly expanding environmental endeavors. The term pertains to the integration of a wide variety of innovations in design, construction and maintenance to reduce consumption of energy, water and other resources, lower CO2 emissions and minimize all manner of other deleterious impacts — both external and internal — associated with the built environment. In addition to boasting lower operating costs, successful green buildings tend to be more comfortable and healthful places to live and work. Green building practices include such things as non-toxic, rapidly renewable and recycled/recyclable construction and furnishing materials; water-conserving and energy-efficient designs and equipment, with an emphasis on renewable energy sources; and the use of environmentally low-impact and “least-toxic” maintenance procedures such as IPM. Although sustainable construction has begun making inroads in residential architecture, it has been the public sector that has most forcefully led the way with promotion of the concept through policy and practice.

As an environmentalist who specializes in structural ecology, I find the green building movement to be one of the most exciting and intriguing developments I’ve seen in a long time. I also don’t mind confessing to a substantial envy of the field, which, unlike structural IPM, never suffered a prolonged period of confused disagreement over definitions and acceptable components. This was primarily due to the rapid ascendance in the late 1990s of a near-universally accepted set of comprehensive standards developed by the U.S. Green Building Council (USGBC): the LEED (Leadership in Energy and Environmental Design) Rating Systems. Organizing a multitude of technical parameters into an elaborate scoring procedure in several functional categories, LEED now constitutes the central code for certification (at four different levels) of sustainability in the built environment. Its methods and elements continue to be adopted worldwide.

As it turns out, LEED has been painfully slow in understanding just what a structural IPM program realistically consists of. The latest version, released in 2013, goes a long way toward improving the previous iterations (which were almost a parody of 1990s-style chemophobic ideology), but still contains several irritating anachronisms that do nothing to bolster its credibility among mainstream IPM practitioners. I will be writing more about this curious situation in the near future, but let’s not get distracted with it now — LEED has always been a work in progress, continually receiving and incorporating feedback from stakeholders, and I have no doubt it will eventually modify its IPM rating into something far more useful than it is today. What I’d like to focus on here is the question — from our own selfish, industry perspective — are green buildings a good thing or not? LEED certainly promotes IPM in the sense of an operating philosophy for a maintenance function, but how intrinsically IPM-friendly are the structures themselves? Are they any more pest-resistant than “non-green” (or less green) buildings of comparable age and size?

My conclusion at this point is that, alas, they are not. One of the primary reasons is that none of the principal elements of sustainable construction have very much applicability to what is required for significant pest prevention. These elements are categorized by LEED as:

  • Sustainable transportation.
  • Sustainable site development.
  • Water efficiency.
  • Energy efficiency.
  • Materials selection.
  • Indoor environmental quality.

This is all great and you can explore the details on the USGBC website ( — but you won’t find such nitty gritty items as cunning structural designs to thwart persistent pigeons, selection of food-service equipment to minimize pest accessibility and facilitate inspection, an emphasis on pest-resistant storage of putrescible waste or intelligent integration of centralized waste management equipment with loading dock configuration. When LEED concerns itself with waste management, for example, it worries about things like source reduction, occupant recycling programs and waste stream audits.

Illusion vs. Reality.

Nevertheless, many of the current generation of green buildings have, at least initially, given the impression that they are superior to conventional structures when it comes to pest deterrence. Here are three reasons why.

First of all, they’re new. Most new buildings tend to be more pest-free than they are after aging for a decade or two. They haven’t begun to comprehensively deteriorate in all of the inevitable macro ways (e.g., settling cracks in the foundation) or micro ones (e.g., loose vent screens). Second, they’re cleaner. Organic residue has only just begun to accumulate in the crevices of kitchens, locker rooms, janitor’s closets and so forth. And third, they tend to be built away from urban core areas, which not only means less external pressure from some common pests that are endemic in that sort of habitat, but also confers a greater chance the loading dock will be better designed simply because there’s more space available for it.

On the other hand, there are several features associated with public and commercial green buildings that are worrisome. They often have operable windows, which are more subject to leaks, maintenance problems and pest penetration through defective screens compared to fixed windows. From an IPM viewpoint, this is an awfully big step backwards. They tend to have raised flooring throughout much of the structure, a superb innovation for cable management and air delivery that also has distinguished itself as an unparalleled rodent refuge and distribution system.

They often have many indoor plants and, in some cases, complex plantscapes with built-in irrigation systems that mimic natural habitats (Figure 1). “Build it and they will come” would be an appropriate pest-perceptive response, although in some cases such installations actually start out “pre-infested” from purchased plant stock. The surrounding landscapes of green buildings often include substantial natural areas or are designed to be more naturalistic than with conventional architecture, often requiring specialized management skills beyond that of the average landscape contractor and frequently serving as habitat for a host of relentless structural invaders (Figure 2, on the right). And as the crowning (literally) addition to their biophilic tendencies, they often have vegetated roofs.

I’m well acquainted with this trend. The federal government installed its first green roof in 1975 and now has more than 1 million square feet of plant-covered roofs nationwide, a fraction of the total that exists throughout the country. Their virtues are often extolled by a growing corps of adherents with an enthusiasm that borders on breathless: improvement of local air quality, additional insulation for the structure and that all-important reduction of the burden on storm water systems and local waterways that is reflected in reduced sewer charges. Actual quantification of these benefits (particularly compared to alternative green options) is still rather sparse, but there is no denying their visual charm, derived from a hobbit-like fusion of the built environment with the natural one.

Nevertheless, good intentions may ultimately be insufficient to counteract the considerable technical challenges inherent in sustainably melding vegetation with building materials, exacerbated by the enduring themes of short-sighted design, sloppy construction, natural deterioration and deferred maintenance. In particular, vegetated coverings would seem to blatantly violate age-old architectural and engineering principles that 1) water, the great destroyer of all things man-made, should be shed as quickly as possible from a building rather than retained close to its shell and 2) any man-made construction should be built so that critical components are easier, not harder, to inspect and service. Since low-slope roofs (which characterize the majority of green roofs) are an inferior way to keep water out of a building, the problem is compounded by covering the membrane system with an elaborate planting matrix that will have to be removed when the inevitable leaks occur. Once again, grand architectural conceptions must rest on the shoulders of the maintenance class (and their perpetually inadequate budgets).

And then there’s the faunal element, which is universally lauded as an unqualified benefit by the green building community. Indeed, a pioneering study in London during 2004 confirmed numerous anecdotal observations that green roofs of all sorts rapidly become colonized by a wide variety of invertebrates, some of which may be uncommon or even rare in adjacent terrestrial habitats. Only time will tell if this happy development in maximizing local biodiversity will always come with a dark side for pest managers, but evidence is accumulating that certain nuisance invaders (e.g., spiders, ants and clover/erythraeid mites immediately come to mind) benefit greatly from large expanses of rooftop vegetation and its associated substrate.

One of the first public building green roofs in Washington, D.C., served as the breeding ground for an enormous population of millipedes that subsequently invaded the structure’s interior en masse. The situation was readily mitigated with a vacuum and better door sweeps, but it was a convincing demonstration that vegetated urban habitats are as likely to be exploited by disruptive species as benign ones.

Beyond all of these factors, however, is the inescapable truth that green buildings are not all that different from their predecessors in many ways. My guess is that, as a group, they’ll continue to turn out pretty much the same as conventional structures from a pest control standpoint. Why? Because they’re buildings and thus susceptible to the same types of challenges that have plagued facilities throughout the ages.

Green or not, they are designed by ambitious architects for looks more than function, they are slapped together by a construction industry that values speed over craftsmanship, they are cared for by overworked maintenance staffs on a disgraceful shoestring and they are occupied by tenants who refuse to store food and clean up after themselves in a responsible manner.

Same Old Same Old.

As one example, I experienced the following items during the first several months of operation of a large office building that received a LEED Silver rating, subsequently upgraded to Gold:

  • Inadequate door sweeps allowed an assortment of small invaders to access the interior, including three species of snakes.
  • As is usual for public structures, the building went online before the exterior shell was fully complete. This led to several memorable indoor raccoon incidents. Premature occupation is virtually guaranteed to maximize human/rat interactions in new buildings located in urban core areas, particularly when the rodents are eventually sealed inside.
  • Doors propped open by occupants taking unauthorized smoke breaks on the green roof resulted in the entry of a small flock of house sparrows. These birds were common on the roof, probably because they like to nip off the edges of sedums, a ubiquitous type of green roof plant. Dealing with them indoors proved to be extremely difficult, due to surreptitious feeding (and trap sabotage) by the inevitable coterie of ornithophilic employees. The enormous open work areas characteristic of modern office buildings, together with easy access up into the ceiling plenum, gave the birds an abundance of space and shelter.
  • Geese quickly found the picturesque settling pond, became a nuisance on the adjacent lawns and sidewalks, and aggressively approached the toddlers for handouts at the day-care center playground.
  • Raised flooring immediately provided an ideal habitat for house mice that had probably been stowaways in boxed material from previous offices. The mice eventually established an enduring foothold throughout the structure due to widespread, irresponsible food caching and waste disposal practices, a global trait among building occupants, green or otherwise.
  • Last, but certainly not least, the gleaming new fitness center began to fill up with wandering German cockroaches — lots of them. It was initially assumed that cartons of infested junk from the old facility were responsible, until it was discovered that the pests were continually being introduced in the bottom of large, plastic carts used by the laundry contractor to collect and return the gym towels (which the company also used interchangeably for the restaurant part of their business!). Sheets of kraft paper that lined the bottom of the carts provided perfect concealment for traveling populations of roaches that feasted on accumulated food remains from tablecloths past, but would then find themselves marooned in a far less favorable environment if they crawled away in the gym. Bed bugs have similarly been recorded as using linen carts to disperse throughout hotels and hospitals. Other common examples of the “Trojan horse syndrome” in public buildings include electronic equipment and modular office cubicles (“systems furniture”) harboring brownbanded cockroaches; trash carts (often introduced by the custodial contractor) with residue containing fruit fly larvae; and household plants (often introduced by the tenants) with soil containing fungus gnat larvae.

The bottom line was that I got to know this young, showcase structure intimately at a time in its life when pest levels in general are typically at their lowest. Truth be told, it wasn’t any more of a headache than any other similar-sized building in my inventory — it’s just that its “green” status was simply irrelevant for my line of work.


This article has been adapted from a forthcoming book on the theory, history and practice of IPM in buildings. The opinions expressed herein are the views of the author and do not necessarily reflect the official policy or position of the U.S. General Services Administration (GSA). The author is entomologist and national IPM Coordinator for the GSA’s Public Building Service in Washington, D.C.

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