Structure Preparation, Sealing, and Tenting
Preparation is a checklist, not a judgement call
Before gas is introduced: confirm occupants, pets, and plants are out; remove or double-bag food, feed, medications, and tobacco as the label requires; open interior doors, closets, cabinets, and drawers so gas reaches them; protect or remove items the label excludes (often foam rubber, mattresses, or certain electronics); and verify no one remains inside. Utilities, pilot lights, automatic doors, and elevators must be handled per label, and any space that could hold a person must be checked and secured.
Sealing and tenting geometry
A fumigation fails at its leaks. Seal ground contact with sand snakes or foam, tape or plug openings, close vents and attic access, and verify the seal before charging. Tarps are commonly 6 mil and must be anchored against wind and secured with ropes or weights; roofs need a cap or "top hat" tied into the wall tarp, and ladders and roof work demand fall protection. Post placards at every entrance after charging and keep them until clearance.
Tarp sizing
Estimate tarp area as roof (or floor plan) area plus wall area, then add roughly 10–15 percent for overlap, tie-offs, and waste.
Worked example: a 30 × 40 ft building with 10 ft walls: roof/floor area = 1,200 ft²; wall area = 2 × (30 + 40) × 10 = 1,400 ft²; total = 2,600 ft²; adding 10 percent gives about 2,860 ft² of tarp.
Traps
Sealing from the outside while open closets remain unopened, forgetting attached garages or crawlspaces, and assuming a tarp is gas-tight when it is merely draped. A short half-loss time during monitoring means go back and seal.