Cockroaches are unwelcome visitors to any home, and while they can be common all year round, summer is their most active time.
They usually live outside, but in dry weather can enter the home looking for water. Also, if the outside population grows large, some may choose to migrate indoors.
Many companies specialise in cockroach and other pest extermination, such as Cong Pest Challenge, Tran's Pest Control, and Premium Pest Control, who you should contact if you have a big cockroach problem.
PestXpert, a supplier of pesticide products, has the following advice for getting rid of them yourself.
Large cockroaches like a damp and cool environment, so they often hide outside in drains, rubbish bins and garden beds. They can also be found under the floor and in basements. Oddly, sometimes they hide under the insulation in the roof, even though it is hot and dry.
Most important, make sure you use a residual spray which is labelled for cockroaches. Outside sprays should last for three months, and inside sprays for up to six months.
Before you use a pesticide, read the label carefully to see if the product can be dangerous to children or pets. Always take care using them around food trees, vegetables or edible plants. If you have a fish tank or fish pond, cover it before spraying.
Outside, use a long lasting residual spray all around the house (1m up the wall and 1m out from it), as well as doors, windows, and other openings.
Inside, spray hiding places such as under sinks, fridges and dishwashers, inside cupboards, and in any cracks and crevices. Use an aerosol with an extendable nozzle.
If there are areas you do not want to spray, place cockroach baits.
Spray the outside perimeter of the home and likely hiding places twice a year
Keep rubbish in sealed bins
Make sure insect screens on the windows and doors are in good shape
Seal any cracks or openings
Avoid storing goods (especially cardboard boxes) under the house
Keep garden beds away from the immediate perimeter of the house