How to use a household surface spray safely, and where it goes

August 11, 2025

Read the label first, and that isn't a formality

A residual surface spray is an insecticide that's designed to stay active on a surface for weeks, which is exactly why it works and exactly why it deserves some care. The label on the bottle carries the approved uses, the surfaces it's safe on, the re-entry time and the first aid advice, and it's specific to that product rather than general.

So the label wins over anything written here or anywhere else. If the two disagree, follow the label.

Worth saying plainly, because the marketing muddies it: low odour doesn't mean low toxicity. It means the solvent has been changed so it doesn't make the room smell. The active ingredient is doing the same job it always did.

What to wear, and what to open

Gloves, and covered arms and legs. Closed shoes rather than thongs. Eye protection if you're spraying anywhere above waist height, because the overspray comes back down. A P2 dust mask if you're doing a whole house or working in a confined space like under a floor.

Open the windows and doors in the room before you start and leave them open while it dries. Turn off any fan that's going to blow it around rather than out.

Then wash your hands before you touch anything else, and wash the clothes separately from the rest of the laundry.

Where it goes

Surface sprays work as a barrier, so you're treating the routes insects travel rather than the middle of a room.

Along skirting boards and around door frames
Window sills and tracks
Around the outside of the house at the base of the wall, and up about 30cm
Under and behind heavy appliances where you can't easily clean
Along the edges of a garage or shed floor

Where it never goes

This is the part the packaging tends to skip over, and it matters more than any of the above.

Not on food preparation surfaces. Not benchtops, not chopping boards, not the inside of a pantry shelf where food sits. Clear the shelf, spray the kickboard and the back corner, let it dry, keep the food off the treated surface.
Not on anything your skin sits on. Bedding, lounges, towels, the dog's bed.
Not on plants. A household surface spray isn't registered for use on edibles or ornamentals and it'll damage a lot of them.
Not near a fish tank. Pyrethroids are extremely toxic to fish. Cover the tank and turn the pump off, or treat a different room.
Not around an open flame. Let it dry before you light a candle or a burner in that room.

Children and pets

Keep both out of the room until the spray has dried completely, which is usually a couple of hours and longer in cold or humid weather. Wet is the risky state. Once it has dried the residue is bound to the surface and is far less available, but that isn't a reason to spray where a toddler crawls or a cat sleeps.

Cats are worth a separate mention because they groom constantly and are more sensitive to some insecticides than dogs are, so anywhere a cat routinely walks and then licks its paws is a place to use a bait instead.

For ants, a bait usually beats a spray

This is the practical bit that saves people repeating themselves. Spraying a trail of ants kills the ants you can see and does nothing to the nest, so they're back in a fortnight and you spray again.

A bait works the other way. The foragers carry it back and it reaches the part of the colony you can't get to, so it's slower to look like it's working and much more likely to actually finish the job. Put the bait on the trail, resist cleaning the trail away while it's working, and leave the spray for the barrier around the outside of the house.

Storing it and getting rid of it

Keep it in the original container with the label on, up high, away from food and out of the sun. Never decant it into a drink bottle. Don't tip leftovers down a drain or onto the garden, and take anything you want rid of to a household chemical collection rather than putting it in the bin.

Shop related products

Antex Insecticide Baits 4 Pack. The better answer for an ant trail indoors.
David Grays Antex Insecticide Granules 500g. For nests and runs outside.
David Grays Ant and Termite Spray 500ml. A smaller spray for spot work rather than a whole house.
Coopex Residual Insecticide Sachet 25g. A concentrate you mix, for treating a larger area.

Did you know we keep the Brunnings Outdoor and Indoor Surface Spray 2L in the shop along with gloves, P2 dust masks, safety glasses and pump sprayers, and none of that's on the website. Give us a ring on (08) 8536 4333 to check what's on the shelf, and the rest of the pest control range is online.