Borer in heritage and special character homes

Is the house scheduled, in a special character area, or neither?

Auckland's Unitary Plan has two separate systems. Scheduled historic heritage places are individually listed in Schedule 14.1, each with its primary features and any exclusions. Special character areas are groups of buildings protected for the collective look of a street or neighbourhood. A house can be in one, both or neither.

Auckland Council points owners to the Unitary Plan schedules and its GeoMaps viewer to check a property, and notes that its schedule is separate from the Heritage New Zealand List. Special character boundaries have been revised in recent plan changes, so check the current maps rather than relying on what applied when you bought. That status shapes everything that follows the inspection.

What can it mean for replacing original exterior timber?

The Unitary Plan's regional policy statement encourages retention and maintenance of scheduled places, and in special character areas requires additions and modifications to maintain the area's character while restricting demolition. Replacing original weatherboards, verandah timber or joinery may therefore need resource consent. Ask Auckland Council before work starts.

Whether a particular repair counts as maintenance, or as an alteration that needs consent, depends on the rules for that place or area and on how the work is done. Like-for-like repair of a few boards in the same profile is a very different proposal from re-cladding a wall in a new material. The inspection does not answer the planning question, but it gives the council and your builder an accurate account of which timber is affected, and how badly.

How does the inspection help keep original fabric?

Holes alone are not a reason to replace timber. The common house borer feeds mainly in sapwood, so a weatherboard or bearer can carry many old holes and still be sound. The inspector probes suspect members and records each as holed but sound, active, or weakened, which is the distinction that decides whether timber can stay.

Treatment of bare timber is explained under treating live borer, and the weatherboards guide covers why painted boards can hide more than they show.

Does the repair also need a building consent?

Building consent is a separate question from resource consent. Under Schedule 1 of the Building Act 2004, repair and maintenance using comparable materials, or replacing a component with a comparable one in the same position, generally needs no building consent. That exemption has limits worth knowing before any heritage repair begins.

• Not covered: complete or substantial replacement of a component that contributes to the building's structural behaviour.
• Not covered: repair or replacement, other than maintenance, of anything that has failed the Building Code's durability requirements.
• Still required: exempt work must comply with the Building Code.
• If unsure: MBIE suggests asking the council for a discretionary exemption, or applying for consent.

Where a repair does need a building consent and affects the primary structure, it is restricted building work that must be done or supervised by a licensed building practitioner. More detail is under borer damage repair.

How do the inspector and the builder work together?

The inspector identifies the beetle, the activity and the affected timber; the builder decides how to repair what has lost strength. On a heritage house it helps if the builder sees the written findings before quoting, so that sound timber is not replaced by default. With your agreement the findings go to a builder who quotes the repair.

Look for a builder who has repaired houses of a similar age and is comfortable splicing or patching rather than replacing whole lengths, and who knows when to send a question to the council. Treatment of the remaining sound timber is best timed after any repairs, so new surfaces and old are covered together, and ahead of the next flight season.

Where are Auckland's heritage and character houses?

Scheduled places and special character areas are spread across Auckland, but the densest concentrations of timber villas and bungalows are in the older inner suburbs. Each house is its own case: two neighbouring houses can have very different borer histories depending on how they were maintained and renovated.

Suburbs with many character houses include Parnell, Ponsonby and Devonport. The typical borer pattern in houses of that era is described under villas and bungalows, and buyers of a character house can book a pre-purchase borer check while their offer is conditional.

Related pages

• Villas and bungalowsWhere borer usually shows in Auckland villas and California bungalows, and in renovations that mix old and new timber
• Borer damage repairWhen borer damage needs a builder, which repairs are exempt from consent, re-piling and the order of work
• Borer in weatherboardsBorer in lower boards and sills, what paint does and does not stop, and replace versus treat versus repaint
• Borer inspectionWhat a borer inspection records, part by part, and what it costs