Termite damage is the most expensive pest problem a homeowner can have and one of the few that standard property insurance does not cover. The reasoning insurers give is that it is a maintenance failure rather than a sudden event, and irritating as that is, it is broadly correct — almost every serious infestation we find traces back to water sitting somewhere it should not.

What termites actually need

Subterranean termites need three things: cellulose to eat, moisture to survive, and a route between the soil and the timber that keeps them out of open air. Remove any one and the colony cannot establish.

Moisture is the one you control.

The drainage audit

Walk the outside of the house during heavy rain. It is unpleasant and it tells you more than any inspection on a dry day.

• Is every downpipe discharging away from the foundation, or against it?
• Does the ground slope away from the wall for the first six feet?
• Are the gutters overflowing anywhere?
• Is there a damp patch on the foundation that is still damp two days later?

Every one of those is a termite invitation, and every one is cheaper to fix than the timber it will eventually cost you.

Break the soil-to-timber contact

• No timber in ground contact: fence posts, deck stringers, stair carriages.
• Keep siding at least six inches clear of finished soil level.
• Mulch no deeper than two inches, and never against the wall.
• Firewood off the ground and away from the building.
• Cardboard out of the crawl space — it is cellulose in a humid void.

Learn the four signs

Mud tubes. Pencil-width earthen tubes on foundation walls or piers. This is the clearest sign there is.

Swarmers and wings. Small piles of identical discarded wings near windows or light fittings, usually in spring.

Hollow or soft timber. Skirting that gives under a screwdriver, or a floor that feels spongy in one spot.

Blistered paint. Looks like water damage on a surface with no water source.

If you find mud tubes, do not knock them down before the inspection. Their shape, position and moisture content tell a technician which species you have and how active the colony is.

Inspect annually

An annual inspection costs a fraction of one repair and is the only reliable way to catch a colony in its first two years, when the damage is still cosmetic. If the property has ever been treated, the annual report is also what proves continuity of protection to an insurer or a future buyer.