New Builds and Renovations: Where Pest Problems Begin

A new home is not a pest-proof home. It is a home with fresh gaps, no established protection, landscaping planted directly against the slab, and no inspection history to compare against.

Renovations add a second problem: the work itself disturbs whatever was already living in the structure. Knowing what to check at each point is what keeps a new build from becoming a five-year project.

How a new build lets pests in

• Landscaping against the wall. Mulch, garden beds and planter boxes installed hard against the slab edge are the classic bridging detail over a barrier.
• Unsealed penetrations. Pipes, conduits, air-conditioning lines and cabling through the slab and cladding are open doors if the sleeve is missing or the sealant has shrunk.
• Wet areas and drainage. New downpipes, poorly graded ground and an unconnected stormwater line create damp zones that attract cockroaches, silverfish and termites.
• Construction residue. Timber offcuts, formwork, packaging and cartons left under the house or in the yard are immediate harbourage.
• No barrier history. Some homes have a physical or chemical barrier with a certificate; some have neither. If you don't have the certificate, you don't know what is under the slab.

In NSW, termite management is a documented system

New residential work is expected to include a termite management system designed to AS 3660.1, with a certificate issued at completion and a plan showing what was installed and where.

Ask for that certificate at handover. It should tell you the barrier type, the areas covered, the exclusions, the inspection intervals that keep the warranty valid, and who to contact. Without it, the warranty is theoretical — and at sale, a buyer's inspector will ask for it.

Renovations disturb what was already there

• Adding a wet area (bathroom, ensuite, laundry) creates a permanently damp zone; check the adjoining frame and floor for existing damage before closing it up.
• Cutting or extending a slab can expose or sever a barrier — and can open a path into a wall cavity.
• Removing a wall often reveals old damage, previous treatments and activity that was never documented.
• Building over a path or old paving leaves a concealed surface against the wall, which is a termite risk and a moisture trap.
• Extending a deck or pergola puts new timber against the house — attachments and stumps need to be detailed so they are not a bridge.

If termite activity or old damage is found during a renovation, stop and get it assessed before the linings go back on. It is the cheapest moment in the project to deal with it.

The first twelve months in a new home

• Month 1: walk the perimeter after landscaping is finished. Check that no bed, mulch or planter is mounded above the slab edge, and that all penetrations are sealed.
• Month 3: check the stormwater actually discharges where it should, and that no ground has settled into a low point against the wall.
• Month 6: look under the house or in the subfloor if there is one, and in the roof space — packaging and offcuts are often still there.
• Month 12: book the first annual termite inspection. This starts the record that matters when you sell.

What to keep in the file

Termite management certificate and barrier plan, the inspector's reports, any treatment records, product and warranty details, and a note of landscaping changes you make. Buyers' inspectors ask for exactly this, and so do insurers in some cases.

Practical prevention that costs nothing

• Keep mulch and soil below the slab edge and weep holes clear
• Store timber, cardboard and garden supplies off the ground and away from the wall
• Fix leaking taps and overflowing downpipes before they create a damp zone
• Don't stack firewood against the house
• Check the roof space and subfloor twice a year with a torch
• Leave at least a hand's width between garden beds and the wall, and never bridge a weep hole

What goes wrong, repeatedly

• Landscaping installed after handover with no reference to the barrier
• A renovation that closes up a wall without inspecting the frame behind it
• Packaging and offcuts left in the subfloor for years
• No certificate, so no enforceable warranty
• The first termite inspection happening after a problem is found, not before

Buying a newly built or renovated home

A fresh renovation is one of the harder properties to assess, because the finishes hide the history.

• Ask for the termite management certificate and barrier plan, and check the plan matches what is actually on site.
• Ask what was found during the renovation, particularly around bathrooms and the frame.
• Look for landscaping already mounded against the slab, and for weep holes that are covered.
• Check that the subfloor and roof space are clear of packaging and offcuts.
• Commission your own building and pest inspection — a new build is not exempt, and a pre-purchase inspection on a renovation often finds concealed work.

Solar, decks and later additions

The most common pest mistakes made after handover are all additions: a deck attached to the house with timber bearers against the wall, a garden bed built up over the weep holes, a shed slab poured without sealing the edges, and solar or air-conditioning penetrations drilled straight through the cladding.

Each is a small job with a large consequence. When a trade drills through a wall, ask them to seal it — and check that they did.

Who owns the barrier after handover

The builder installs the system; the owner keeps it valid. Most termite barrier warranties are conditional on annual inspections by a licensed technician, on landscaping not being altered against the slab, and on the owner reporting any moisture or damage promptly.

That means two simple acts protect a new home. Book the inspection every year without being reminded, and tell your inspector before you change landscaping, add a deck or pave against the wall — those are precisely the changes that void cover.

The handover file: five documents to insist on

Most owners receive a folder of appliance manuals and a warranty booklet and never see the pest paperwork. If you are buying a new build, ask for these specifically.

The termite management system installation certificate, which states what was installed, where, and when. The durable notice, which should be attached in a serviceable location, usually the meter box or under the sink, telling future owners a system exists and who installed it. The product specification or technical data for whatever was used, so a future technician is not guessing. Any compliance certificate issued by the installer, where the system requires one. And the maintenance schedule, because almost every system installed in a new home carries conditions that keep the warranty valid.

Where a home is being sold and the file cannot be produced, that is a negotiating point rather than a reason to walk. But a missing durable notice is meaningful: it means the next owner of the property may not know a system exists, and one of the most common causes of barrier failure is a system being cut, buried or built over because nobody knew it was there.

Landscaping that undoes a barrier

The barrier in a new home is usually installed before the landscaping, and the landscaping is what quietly defeats it. Retaining walls built over the line. Garden beds raised against a slab. A paved path that hides the slab edge and stops it being inspected. An irrigation line that keeps the soil at the wall permanently damp.

None of these are unusual, and none are malicious. They are the natural consequence of building a garden around a house without knowing where the protected line is.

Two habits prevent most of it. Keep soil or mulch below the damp course and below the slab edge by sight, not by memory, so the boundary line stays visible. And keep paving at least a hand's width away from the wall so the slab edge can be seen. Where a raised bed is genuinely wanted, a physical barrier or a chemical barrier renewal along that specific wall is the way to keep both.

Anything that changes the ground level against the house changes the barrier. That is the single rule worth remembering.

Extensions, decks and the chain of certificates

Every time work is done that touches the barrier, the documentation chain should extend. A deck attached to the rear wall of a house with a slab barrier is one of the most common compromise points in domestic construction, and it is entirely preventable.

If a deck is added, the fixing detail at the wall should not create a path over the barrier, and the barrier along that wall should be re-established and documented. If an extension is built, the new work carries its own system and its own certificate, and the junction between old and new is where inspections should focus for the next decade.

The failure pattern we see is a house with three generations of work and one certificate, from 2009, for the original build. Every later addition is undocumented, and a technician arriving at the property has no way of knowing what is protecting which section of wall. Keeping the file current is the owner's job, and it takes about five minutes per project.

Statutory warranty: how long you actually have

NSW gives homeowners statutory protection on residential building work, and the time limits are worth knowing because they set the practical deadline for raising a barrier defect with a builder.

Broadly, the warranty period is six years for major defects, that is, defects that affect the structure or make the building unsafe or uninhabitable, and two years for other defects, running from completion. A missing or incorrectly installed termite management system can fall into either category depending on the defect and the consequences.

What follows from that is simple. Document the handover properly, inspect within the first twelve months while everything is fresh, and raise defects in writing while the clock is running. A call to the builder two years and one month after handover about a barrier that was never installed properly is a much harder conversation than the same call at eight months.

Twelve months in: what the first inspection should confirm

The first inspection after handover is the most useful one a new home will ever have, because it is the only one where the baseline is documented and the building is still unaltered.

What it should confirm: the system is present where the certificate says it is, the durable notice is in place, the barrier has not been damaged by landscaping, paving or the bin pad, ground levels are still below the damp course, and the subfloor or slab edge is accessible. Any gap between what the certificate describes and what is actually there is best raised with the builder while warranties are fresh and they are still motivated.

Book it before the twelve-month mark, not after.

And if the builder cannot produce the certificate at all, get a system assessed and a new certificate issued before you landscape anything. It costs less than a garden bed, and it is the only point in the life of the house where the barrier is easy to reach and easy to prove. After that, every visit involves moving something out of the way first, and a barrier nobody can see is a barrier nobody maintains.

How Accurate Pest Control can assist

We inspect new builds and renovations, install and certify termite barriers, and set up the annual inspection schedule that keeps a new home's protection intact.

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