When a home undergoes tenting for structural fumigation, safety is the top priority. Many homeowners may not realize that accessory dwelling units (ADUs) or converted garages attached to the main house often cannot be occupied during the fumigation process. This restriction is crucial because of shared building systems like electrical conduits and the risk of fumigant gas leakage between connected spaces.

Why ADUs and Converted Garages Must Be Vacant During Tenting

Shared Electrical and Utility Conduits

In many modern homes, ADUs or converted garages are integrated into the overall building infrastructure. This means they often share electrical wiring, conduit systems, plumbing, and sometimes HVAC ducts with the main structure. These shared conduits create pathways that allow fumigant gases, such as Vikane (sulfuryl fluoride), to travel from the tented main house into adjoining spaces.

Risk of Gas Leakage and Exposure

Vikane gas is highly effective for pest elimination but is also toxic to humans and pets at fumigation concentrations. Although the main structure is sealed with a tent during fumigation, the interconnected conduits can allow the gas to seep into connected units like ADUs or garages. This leakage can create hazardous conditions in those spaces, making them unsafe for occupancy until the fumigation and aeration process are complete.

Building Codes and Safety Regulations

Fumigation companies and regulatory agencies strictly enforce safety protocols to prevent accidental exposure. Because of the risk posed by shared utilities and gas migration, occupants are required to vacate not only the main home but also any attached or connected units during the entire fumigation period. This precaution ensures that no one is inadvertently exposed to toxic gases.

What Homeowners Should Know Before Scheduling Fumigation

• Inform Your Pest Control Provider: Let them know about any ADUs, converted garages, or other attached living spaces so they can plan accordingly.
• Plan for Temporary Relocation:All occupants in the main structure and connected units must vacate for the duration of the fumigation, including aeration time.
• Seal or Disconnect Utilities:Professionals may take extra steps to seal or isolate shared conduits to minimize gas migration risks.
• Post-Fumigation Safety Checks: After aeration, the fumigation company will verify that gas levels are safe in all parts of the property before allowing re-entry.