First-ever national guidelines published on designing buildings to prevent pests

Pest Prevention Guidelines developed by a coalition led by San Francisco Department of the Environment

Is your building pest-proof? The San Francisco Department of the Environment this week unveiled a new resource for designing buildings that are more resistant to common pests, such as rats, termites, pigeons and cockroaches. The free guidelines aim to reduce both pests and the use of pesticides for the lifetime of a building, thereby improving indoor air quality, reducing toxics exposure, and more effectively managing pests.

 “The standard definition of ‘green building’ has mostly included considerations around location, energy use and recycling materials,” said Melanie Nutter, Director of the San Francisco Department of the Environment. “Through today’s release of the Pest Prevention by Design guidelines we are now expanding the definition to incorporate innovative design features which can reduce lifetime exposure to pests and pesticides.  These guidelines are an excellent resource for building professionals in learning how to design and build simple cost effective solutions to prevent the need for toxic chemicals to eradicate pests.”

The idea for the project, entitled “Pest Prevention by Design”, came from San Francisco’s Integrated Pest Management (IPM) Program, which is responsible for pest management and pesticide reduction on City-owned properties.  The program had reduced city government’s pesticide use by 80% in its first ten years, but as the reduction trend flattened out, it became clear poor design was a key problem, both for landscapes and buildings.

“There are a lot of events beyond our control that affect pesticide use, such as increases in mosquito-borne diseases,” said Chris Geiger, San Francisco Department of the Environment’s IPM Program manager. “But bad design is something we are able to address, and its effects will last for generations.”

The guidelines include measures appropriate for the design stage of a new building or for renovations of existing buildings. Examples include using stainless steel mesh to exclude termites, putting caps on roof tiles to reduce bird and rat infestations, sloping windowsills to discourage pigeons, and building in hatches to permit easier inspections of foundations. 

“Pest prevention is an important part of the design for a lifetime of living and working in a building,” said Margie O’Driscoll, Executive Director of American Institute for Architects San Francisco. “We can avoid the use of harmful pesticides by designing pests OUT of the structures we inhabit- schools, homes and offices- 90% of our lives. Kudos to the San Francisco Department of the Environment for developing these landmark guidelines that fill a critical need.”

The peer-reviewed guidelines incorporate a year’s worth of discussions by a national committee of experts, including architects, engineers, pest control representatives, and pest management experts.  The Center for Environmental Health was contracted to coordinate the project, and the International Code Council reviewed the final document.

“For too long people have thought that the best way to deal with bugs is to ‘kill them dead,' ” said Caroline Cox of the Center for Environmental Health. “But our new tool lets people know that keeping pests out in the first place can eliminate pesticides and other chemicals that can harm their children and families.”

Contrary to popular belief, more pesticides are used in urbanized areas than in agriculture.  According to the California Department of Pesticide Regulation, about 12.6 million pounds of pesticides were used in California’s buildings in 2010, and this includes only products used by professional pest control businesses.  The actual amount is much more, since about 2/3 of all pesticides used are either products sold to consumers or water treatment chemicals, neither of which are recorded in the state’s databases.

Both pests and pesticides pose health hazards in buildings.  Detritus from cockroaches, mice and other pests are known to be among the most common allergens in homes.  In a study of seven urban areas[1], the 73% of homes were infested with cockroaches and 49% were infested with mice. Other studies have shown that toddlers exposed to pesticides are twice as likely to develop asthma[2], an affliction that costs the U.S. $56 billion each year, with the highest prevalence among the poor. 

“The 10 key principles of pest prevention and their specific application to various building areas, such as the kitchen, bedroom and bathroom, is a focused approach that allows the effective use of pest prevention methods” said Dave Walls, International Code Council Executive Director of Sustainability Programs. “Less pesticides and less pests will undoubtedly result in healthier building environments and cost savings at the same time”.

The Pest Prevention by Design Guidelines was funded by the US Centers for Disease Control and Prevention as part of a larger project addressing health disparities in low-income housing. The document is available on the San Francisco Department of the Environment’s website at:

[1] Crain EF, Walter M, O’Connor GT et al. 2002. Home and allergic characteristics of children with asthma in seven U.S. urban communities and design of an environmental intervention: the Inner-City Asthma Study. Environmental Health Perspectives. 110(9): 939-45.

[2] Salam MT, Li YF, Langholz B, Gilliland FD. 2004. Early-life environmental risk factors for asthma: findings from the Children’s Health Study. Environmental Health Perspectives 112(6): 760-765