Carpenter ants easily excavate foam insulation to build nests. When water leaks in, the foam holds moisture and heat against the wood. Moist, warm wood is the perfect environment for carpenter ants to thrive. Pay attention for water leaks and ant activity if you have blown in foam insulation. A routine pest inspection of accessible spaces with blown in foam insulation may allow for early detection of insect infestation. The inspector will look for live and dead ants, excavated wood and foam insulation, and evidence of water stains. Excavated wood and foam insulation will be pushed out. This excavated material makes piles sometimes right under the nest opening. In some cases, the ants will carry and drop the frass a distance from the nest opening.
Similar to the issues presented by rigid foam insulation many years ago, the pest control industry is keenly aware of the opportunities and challenges the widespread use of foam insulation has created. Foam insulation and tightly built homes can make small water leaks harder to detect. Carpenter ants love wet wood to start a nest. The insulation has the additional benefit of being very warm keeping the carpenter ant nest active much later in the year. A home with this type of insulation needs a regular inspection by pest control technicians.