Whole house fumigation is a pest control method that seals an entire home under tarps and fills it with a lethal gas to eliminate insects, most commonly drywood termites. The process typically spans three days and two nights, costs $1 to $2 per square foot, and requires everyone (including pets and plants) to vacate the home until gas levels drop below 1 part per million.
When Fumigation Is Necessary
Whole house fumigation exists primarily for one pest: drywood termites. Unlike subterranean termites that enter from the soil, drywood termites live entirely inside the wood of your home, forming colonies that can be scattered across walls, attics, and framing members you can’t see or reach. That hidden, spread-out nature is exactly why fumigation becomes the recommended option.
Localized spot treatments work when an infestation is limited to a single board or small cluster of boards. The problem is that current detection methods aren’t reliable enough to guarantee you’ve found every colony. A termite inspector may identify damage in one area, but there’s no way to confirm additional colonies aren’t hiding deeper in the structure. Whole house fumigation solves this by treating accessible and inaccessible infestations simultaneously. The gas penetrates into wood throughout the entire structure, reaching colonies that no drill or injection could.
Fumigation is also used for severe infestations of wood-boring beetles and, in some cases, bed bugs that have spread throughout a home. But drywood termites account for the vast majority of residential fumigations.
What Happens During the Three-Day Process
Day 1: Tenting and Gas Release
A fumigation crew covers the entire home with large nylon tarps, sometimes weighing over 150 pounds each, dragging them across the roof and securing them at the foundation with sand-filled tubes called “sand snakes.” Inside, a licensed fumigator confirms that all food, medicine, plants, people, and pets have been removed. Interior doors, cabinets, and drawers are opened so gas can circulate freely, and fans are positioned to distribute it evenly.
Secondary locks go on every entry point, and warning signs are posted around the perimeter. A tear-inducing warning agent (chloropicrin) is released first. At concentrations above 2 ppm, this chemical causes enough eye and throat irritation to force anyone who accidentally enters back outside. It’s a safety measure, not the treatment itself. Once the warning agent is in place, the fumigator introduces the actual fumigant into the sealed structure. The gas remains trapped inside for a predetermined exposure period, typically 18 to 24 hours.
Day 2: Aeration
After the exposure period, a licensed fumigator opens a pre-installed ventilation system that allows fresh air to flow through the home and push the gas out. This aeration phase runs for the rest of the day and overnight.
Day 3: Clearance and Re-Entry
The crew removes the tarps. A fumigator then takes air samples from interior living spaces using specialized detection equipment. Federal law requires gas concentrations to measure below 1 part per million before anyone can return. Once clearance is confirmed, a re-entry notice goes on the front door listing the exact date and time the home was certified safe. Secondary locks and warning signs come down, and you can move back in.
How the Fumigant Works
Nearly all residential fumigations use a single chemical: sulfuryl fluoride. It’s a gas at room temperature, which allows it to penetrate deep into wood where termites live. Inside the insect’s body, sulfuryl fluoride breaks down into fluoride and sulfate. The fluoride disrupts the insect’s ability to metabolize stored fats and carbohydrates, essentially cutting off its energy supply. The insect attempts to switch to protein as a backup fuel source, but the metabolic rate can’t keep up. The result is death across all life stages, including eggs, which are notoriously difficult to kill with other treatment methods.
Sulfuryl fluoride leaves no lasting residue in the home. That’s both an advantage and a limitation. It means you don’t have chemical deposits on surfaces after treatment, but it also means fumigation provides zero protection against future infestations. New termites can colonize the same home weeks or months later.
What It Costs
For most homes, fumigation runs between $1 and $2 per square foot. A 2,000-square-foot house would fall in the $2,000 to $4,000 range before any add-ons. Several factors push that number higher or lower.
- Home size and complexity: Multi-story homes, crawl spaces, and large attics all require more gas, more tarp material, and more labor. Wood-frame construction, which is more susceptible to termite damage, may need more intensive treatment than concrete or masonry structures.
- Severity of infestation: A mild, localized problem might be treatable with spot treatments or bait systems, saving you the full fumigation cost. Severe drywood infestations that have spread throughout the structure require higher gas volumes and longer exposure, increasing the price.
- Structural extras: Homes with basements, crawl spaces, or extensive attic areas can add $500 to $1,500 in extra charges. If subterranean termites are also present, trenching and baiting systems around the foundation may add another $800 to $2,500.
- Location: Coastal areas with high termite pressure and strong demand tend to charge more. Central and inland regions are often more competitive.
- Season: Termite swarms peak in spring and summer, and fumigation companies get busiest during those months. Scheduling during fall or winter, when demand drops, may get you a better rate.
Preparing Your Home
Preparation is one of the most time-consuming parts for homeowners. You need to remove or double-bag in special fumigation bags all food, medicine, pet food, vitamins, and anything consumable that isn’t in a sealed glass or metal container with the original manufacturer’s seal intact. Opened bottles, plastic-wrapped items, and cardboard-boxed foods all need to come out or go into the bags your fumigation company provides.
All people and pets must leave, including fish (the gas is highly toxic to aquatic life) and any indoor plants. You’ll need to turn off pilot lights and gas-fed appliances, and your fumigator will typically coordinate with your gas company. Exterior landscaping that touches the house may need to be trimmed back so the tarps can seal properly against the foundation. If you have an irrigation system on a timer, shut it off so water doesn’t pool under the tarps.
Plan for two nights away from home, minimum. Some fumigations extend to three nights depending on the structure’s size and construction. Your fumigation company will give you a specific timeline.
Risks to Your Roof and Property
The tenting process itself can damage your home, and this catches many homeowners off guard. Crews drag heavy tarps across the roofline, and technicians walk on the roof to position and secure them. The risk depends almost entirely on your roofing material.
Asphalt shingles hold up well. You might see minor scuffing of the surface granules, but structural breakage is extremely rare. Wood shake roofs carry moderate risk, especially older ones where the wood has become brittle and prone to splitting under foot traffic. Concrete tiles are high risk because their hollow profiles can crack cleanly under a technician’s weight. Spanish clay (terra cotta) tiles are the most fragile of all. Some fumigation companies will refuse to tent a two-story home with clay tiles unless specialized scaffolding is set up to keep crews off the roof entirely, and that adds significant cost.
Before signing a fumigation contract, read the liability waiver carefully. Most operators explicitly state they aren’t responsible for broken roof tiles, damaged satellite dishes, or bent gutters. To protect yourself, take high-resolution photos of your roof before tenting, ideally using a drone or hiring a roofer for a quick inspection. Repeat the documentation immediately after the tarps come down. If damage occurs, that before-and-after evidence is what you’ll need to file a claim with your homeowner’s insurance.
After Fumigation: What to Expect
Once you receive the re-entry notice and return home, the gas itself is gone. Sulfuryl fluoride dissipates rapidly and doesn’t cling to fabrics, surfaces, or food containers that were properly sealed. You don’t need to wash every surface in your house, though many people choose to wipe down countertops and tables for peace of mind.
Dead termites won’t necessarily fall out of the walls the day you return. Over the following weeks, you may notice small piles of wings or fecal pellets (tiny, wood-colored granules) dropping from exit holes as dead colony members break down. This is normal and actually a sign the treatment worked. If you’re still seeing fresh pellets months later, that could indicate a new infestation rather than a remnant of the old one, since fumigation offers no residual protection.
Many pest control companies include a warranty period, typically one to two years, covering retreatment if drywood termites reappear. Some offer extended warranties for an additional fee. Check the terms before your fumigation, not after, since warranty coverage varies widely between companies.