Structural Fumigation Volume Calculator: Cubic Feet and How Much to Charge

A real house is not one box. We sum the main living area, a pitched attic (taken at half its bounding box to approximate the triangular cross-section), a raised-foundation crawlspace, an attached garage, and any patios or carports into one total enclosed volume. Tent fumigation is priced per 1,000 ft³, so we also show the thousand-ft³ figure that sizes the quote.

living   = sqft × ceiling           (or L × W × H)
attic    = L × W × ridge ÷ 2        (half of the bounding box)
crawl    = L × W × height           (raised foundation only)
garage   = L × W × H
patios   = Σ (L × W × H)
total    = living + attic + crawl + garage + patios
priced   = total ÷ 1,000            (the fumigation pricing unit)

The price: the volume charge is the thousand-ft³ figure at your own rate. Your minimum is a floor on that charge, and the add-on lines you enter are added after the floor, so a minimum can never swallow work you quoted separately. The effective rate tells you what the finished job actually earns per 1,000 ft³ once the minimum and the add-ons are in.

volume charge   = (total ÷ 1,000) × your rate per 1,000 ft³
base charge     = max(volume charge, your minimum charge)
add-ons         = Σ (tarp, monitoring, clearance, other)
job price       = base charge + add-ons
effective rate  = job price ÷ (total ÷ 1,000)

Worked example (illustrative figures an operator typed, not a market rate): a 40 × 60 × 12 ft structure is 28,800 ft³, or 28.8 thousand ft³. At an operator-entered 150 per 1,000 ft³ the volume charge is 28.8 × 150 = 4,320. Add tarp 400, monitoring 250 and clearance 175 and the add-ons come to 825, so the job price is 4,320 + 825 = 5,145. The minimum case: a 3,200 ft³ job at the same 150 per 1,000 ft³ is only 480, so a 950 minimum floors the base at 950, and a 400 tarp line on top makes the job price 1,350. Both figures are arithmetic on numbers the operator supplied: we publish no rate, no minimum and no add-on price.

Where the price numbers come from: you. There is no published, verifiable market rate for structural fumigation, so this tool ships none and invents none. The rate, the minimum and every add-on are your own figures, and the arithmetic is the only thing we supply.

Measure enclosed volume from the exterior eaves — the trade measures from outside; interior-only dimensions under-size the tent. The attic ÷2 is a symmetric-gable approximation (it averages ridge height to the eave) — hip and complex roofs are over- or under-estimated. Per-section formulas follow Homesteady's "How to Calculate Cubic Feet for Fumigation" and GC Termite Control's measuring guide (the 60 × 30 × 8 = 14,400 ft³ and 40 × 60 × 12 = 28,800 ft³ worked examples). This is a cubic-footage worksheet that sizes the job — it emits no fumigant quantity; the EPA-registered product label governs the dose.

Where the label classifies the product as a restricted-use pesticide, the certification category, the supervision and the record-keeping that go with that classification apply to the whole job, not just the dose. Clearance and re-occupancy are their own step, and the re-entry interval timer turns the interval you read off the label into a posted date and time. On the commercial side of a drywood job, whole-structure work is usually quoted against the alternatives, which the termite treatment cost estimator lays out, with any renewable warranty priced by the what a renewable warranty costs to carry.