How can you treat foam board insulation with closed-cell consistency that doesn't allow penetration from surface application?

The treatment of foam board insulation with closed-cell consistency requires an approach that ensures penetration for effective pest control, as simply applying a surface treatment would not address the potential presence of termites or other pests that may be within the material or adjacent areas.

Injection and surface spray as a combination treatment method enhances the capability to reach areas that a surface application alone cannot. When one injects the treatment directly into the insulation, it allows the pesticide to penetrate fully, targeting any hidden infestations. This is particularly crucial for materials like closed-cell foam, which are designed to resist penetration. Surface spray serves to create a protective barrier at the exterior, preventing pests from accessing the insulation.

The other methods listed may not achieve the desired efficacy. Surface spray alone would not penetrate the foam effectively, and foam applications are typically meant for other types of treatments rather than for direct pest control in closed-cell scenarios. Heat treatment, while effective for some types of infestations, may not be practical or effective for foam insulation without the risk of damaging the material itself.

Thus, the combination of injection and surface spray is the most comprehensive treatment method for addressing pest management in closed-cell foam board insulation.