Fumigation vs Spray Treatment: What's the Difference?
Short answer: Spray treatment applies liquid pesticide to surfaces and harborage zones. Suitable for most pests; residents stay home during application with 2-4 hour re-entry after. Fumigation seals the area and applies gas or heat (55-60°C) to penetrate all surfaces and voids. Required for bed bugs (heat method), severe stored product infestations, and some drywood termite situations. Costs 3-10x more and requires occupant evacuation for 4-24 hours.
The terms fumigation and spray treatment are sometimes used interchangeably, but they describe fundamentally different methods with different applications, costs, and requirements. Understanding the difference helps you know what to expect from your treatment and why each method is chosen for specific pest situations.
Spray Treatment Explained
Residual spray treatment is the standard method for the majority of residential and commercial pest control situations. A licensed operator applies a liquid pesticide formulation to specific surfaces, harborage zones, and entry points using a calibrated pump sprayer or motorised sprayer. The chemical deposits on treated surfaces and kills pest insects on contact for the residual duration of the product (3-16 weeks depending on product and environment).
Spray treatment is applied in zones: internal skirting boards and wall junctions, kitchen and bathroom harborage areas, subfloor timbers, roof void (where dust is more common than spray), and external perimeter. Different products are used in different zones: gel bait in kitchen harborage, residual pyrethroid on internal surfaces, dust in enclosed voids, and heavier concentrate on external perimeter. Occupants can remain in the property during external-only treatment; internal treatment requires a 2-4 hour re-entry period for surfaces to dry.
Fumigation Explained
Fumigation is a sealed-environment treatment that fills an enclosed space with lethal concentrations of gas or heat. Two primary fumigation methods are used in Brisbane pest control.
Heat fumigation (thermal treatment)
The most common "fumigation" method for residential bed bug treatment. The property or room is sealed and heated to 55-60°C using specialised heating equipment and maintained at that temperature for 90+ minutes. Heat penetrates all surfaces, voids, furniture, and harbourage zones and kills all life stages (eggs, nymphs, adults) in a single visit. No chemical residue remains after treatment. All occupants, pets, plants, and heat-sensitive items must be removed. Re-entry is typically 4-6 hours after the heating period ends.
Chemical fumigation (gas fumigation)
A sealed tent or sealed building is filled with a fumigant gas (methyl bromide or sulfuryl fluoride) to kill pests throughout the structure. Used for drywood termites (rare in Brisbane's subterranean termite environment), severe stored product pest infestations in commercial warehousing, and some heritage timber treatments. Requires specialist licensing beyond standard pest management. Re-entry 12-24 hours after fumigant clearance. No ongoing residual protection after treatment.
Residual spray treatment
Liquid pesticide applied to targeted surfaces and harborage zones. Kills on contact and leaves residual protection for 3-16 weeks.
Heat fumigation (bed bugs)
Room or property heated to 55-60°C for 90+ minutes. Kills all life stages in a single visit. No chemical residue after treatment.
When Each Method Is Used
| Pest / Situation | Standard spray | Fumigation / Heat |
|---|---|---|
| General household pests (ants, spiders, cockroaches) | Yes: standard method | Not required |
| German cockroach infestation | Gel bait program (3-visit) | Heat as alternative if severe |
| Bed bugs | Chemical 3-visit program | Heat treatment preferred (single-visit) |
| Fleas | IGR spray to carpets and furnishings | Not required |
| Rodents | Bait stations + exclusion | Not applicable |
| Termites (subterranean) | Chemical barrier (Termidor); baiting | Gas fumigation for drywood only |
| Stored product pests (commercial) | Limited effectiveness in stock | Gas fumigation for severe cases |
| End-of-lease general pest | Standard spray: certificates available | Not typically required |
| Rental between tenancies (bed bugs) | 3-visit chemical program | Heat preferred for single-visit clearance |
Safety Considerations
Spray treatment
Standard spray treatment uses APVMA-approved products applied at label rates. Internal surfaces are safe for re-entry after 2-4 hours for dry surfaces. Gel bait has no re-entry restriction. Pets should be removed from treatment areas for 2-4 hours after spray. Fish tanks should be covered and pumps turned off before internal spray; birds should be removed. Full safety information at our pest control safety guide.
Heat fumigation
Heat fumigation requires removal of all occupants, pets, plants, temperature-sensitive electronics, medications, and perishable foods from the treated area. The operator provides a preparation checklist. No chemical residue remains after heat treatment, so there are no ongoing safety restrictions after re-entry. The property can be used normally once the re-entry clearance period is complete and the space has been ventilated.
Gas fumigation
Chemical fumigants require specialist licensing to apply and are subject to stricter regulatory controls than standard pest management products. Clearance testing is conducted before the re-entry period is confirmed. Gas fumigation is a rare treatment in residential Brisbane pest control but is used for drywood termites in heritage properties and commercial grain storage applications.
Cost Summary
The cost difference between spray and fumigation reflects the equipment, specialist licensing, preparation requirements, and treatment time involved. Standard spray treatment for a Brisbane house: $180-$320. Heat fumigation for a single bedroom: $600-$1,200. Heat fumigation for a full property: $1,200-$2,500. Gas fumigation for a residential property: $2,500-$5,000+ depending on size. Full pricing detail at the pest control pricing guide.
Which Method Do You Need?
Understanding the Term Fumigation in Practice
In Australian pest control, fumigation is sometimes used loosely to describe any pesticide treatment including standard spray. True fumigation requiring full occupant evacuation is a specialist method. When booking, ask specifically whether you need to leave the property: 2-4 hours means standard spray treatment; 4+ hours means heat fumigation; 12-24 hours means gas fumigation. This distinction determines cost and preparation required. For the vast majority of Brisbane residential pest programs, spray treatment is the correct method. Fumigation arises most commonly in Brisbane for bed bug heat treatment. Termite control uses chemical soil barriers and baiting systems rather than building fumigation. If you have been quoted for fumigation for general household pests and want a second opinion, call 0406 178 471. Full method details at the treatment methods page.
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Frequently Asked Questions
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